| IMPLEMENTATION (57522) | IMPLEMENTATION (62588) |
|---|---|
| 1# NOTE: this is from original KAME distribution. 2# Some portion of this document is not applicable to the code merged into 3# FreeBSD-current (for example, section 5). 4 |
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| 1 Implementation Note 2 3 KAME Project 4 http://www.kame.net/ | 5 Implementation Note 6 7 KAME Project 8 http://www.kame.net/ |
| 5 $FreeBSD: head/share/doc/IPv6/IMPLEMENTATION 57522 2000-02-26 19:44:12Z shin $ | 9 $FreeBSD: head/share/doc/IPv6/IMPLEMENTATION 62588 2000-07-04 16:35:31Z itojun $ |
| 6 71. IPv6 8 91.1 Conformance 10 11The KAME kit conforms, or tries to conform, to the latest set of IPv6 12specifications. For future reference we list some of the relevant documents 13below (NOTE: this is not a complete list - this is too hard to maintain...). 14For details please refer to specific chapter in the document, RFCs, manpages 15come with KAME, or comments in the source code. 16 | 10 111. IPv6 12 131.1 Conformance 14 15The KAME kit conforms, or tries to conform, to the latest set of IPv6 16specifications. For future reference we list some of the relevant documents 17below (NOTE: this is not a complete list - this is too hard to maintain...). 18For details please refer to specific chapter in the document, RFCs, manpages 19come with KAME, or comments in the source code. 20 |
| 17Conformance tests have been performed on the KAME STABLE kit | 21Conformance tests have been performed on past and latest KAME STABLE kit, |
| 18at TAHI project. Results can be viewed at http://www.tahi.org/report/KAME/. 19We also attended Univ. of New Hampshire IOL tests (http://www.iol.unh.edu/) 20in the past, with our past snapshots. 21 22RFC1639: FTP Operation Over Big Address Records (FOOBAR) 23 * RFC2428 is preferred over RFC1639. ftp clients will first try RFC2428, 24 then RFC1639 if failed. 25RFC1886: DNS Extensions to support IPv6 --- 41 unchanged lines hidden (view full) --- 67RFC2467: Transmission of IPv6 Packets over FDDI Networks 68RFC2472: IPv6 over PPP 69RFC2492: IPv6 over ATM Networks 70 * only PVC is supported. 71RFC2497: Transmission of IPv6 packet over ARCnet Networks 72RFC2545: Use of BGP-4 Multiprotocol Extensions for IPv6 Inter-Domain Routing 73RFC2553: Basic Socket Interface Extensions for IPv6 74 * IPv4 mapped address (3.7) and special behavior of IPv6 wildcard bind | 22at TAHI project. Results can be viewed at http://www.tahi.org/report/KAME/. 23We also attended Univ. of New Hampshire IOL tests (http://www.iol.unh.edu/) 24in the past, with our past snapshots. 25 26RFC1639: FTP Operation Over Big Address Records (FOOBAR) 27 * RFC2428 is preferred over RFC1639. ftp clients will first try RFC2428, 28 then RFC1639 if failed. 29RFC1886: DNS Extensions to support IPv6 --- 41 unchanged lines hidden (view full) --- 71RFC2467: Transmission of IPv6 Packets over FDDI Networks 72RFC2472: IPv6 over PPP 73RFC2492: IPv6 over ATM Networks 74 * only PVC is supported. 75RFC2497: Transmission of IPv6 packet over ARCnet Networks 76RFC2545: Use of BGP-4 Multiprotocol Extensions for IPv6 Inter-Domain Routing 77RFC2553: Basic Socket Interface Extensions for IPv6 78 * IPv4 mapped address (3.7) and special behavior of IPv6 wildcard bind |
| 75 socket (3.8) are supported. | 79 socket (3.8) are, 80 - supported and turned on by default on KAME/FreeBSD[34]x 81 and KAME/BSDI4, 82 - supported but turned off by default on KAME/NetBSD, 83 - not supported on KAME/FreeBSD228, KAME/OpenBSD and KAME/BSDI3. |
| 76 see 1.12 in this document for details. 77RFC2675: IPv6 Jumbograms 78 * See 1.7 in this document for details. 79RFC2710: Multicast Listener Discovery for IPv6 80RFC2711: IPv6 router alert option | 84 see 1.12 in this document for details. 85RFC2675: IPv6 Jumbograms 86 * See 1.7 in this document for details. 87RFC2710: Multicast Listener Discovery for IPv6 88RFC2711: IPv6 router alert option |
| 81draft-ietf-ipngwg-router-renum-08: Router renumbering for IPv6 82draft-ietf-ipngwg-icmp-namelookups-02: IPv6 Name Lookups Through ICMP 83draft-ietf-ipngwg-icmp-name-lookups-03: IPv6 Name Lookups Through ICMP 84draft-ietf-pim-ipv6-01.txt: PIM for IPv6 | 89RFC2732: Format for Literal IPv6 Addresses in URL's 90 * The spec is implemented in programs that handle URLs 91 (like freebsd ftpio(3) and fetch(1), or netbsd ftp(1)) 92draft-ietf-ipngwg-router-renum-10: Router renumbering for IPv6 93draft-ietf-ipngwg-icmp-name-lookups-05: IPv6 Name Lookups Through ICMP 94draft-ietf-pim-ipv6-03.txt: PIM for IPv6 |
| 85 * pim6dd implements dense mode. pim6sd implements sparse mode. | 95 * pim6dd implements dense mode. pim6sd implements sparse mode. |
| 86draft-ietf-dhc-dhcpv6-14.txt: DHCPv6 87draft-ietf-dhc-v6exts-11.txt: Extensions for DHCPv6 | 96draft-ietf-dhc-dhcpv6-15.txt: DHCPv6 97draft-ietf-dhc-dhcpv6exts-12.txt: Extensions for DHCPv6 |
| 88 * kame/dhcp6 has test implementation, which will not be compiled in 89 default compilation. | 98 * kame/dhcp6 has test implementation, which will not be compiled in 99 default compilation. |
| 90draft-itojun-ipv6-tcp-to-anycast-00: | 100draft-itojun-ipv6-tcp-to-anycast-00.txt: |
| 91 Disconnecting TCP connection toward IPv6 anycast address | 101 Disconnecting TCP connection toward IPv6 anycast address |
| 92draft-yamamoto-wideipv6-comm-model-00 93 * See 1.6 in this document for details. 94draft-ietf-ipngwg-scopedaddr-format-00.txt: | 102draft-ietf-ipngwg-scopedaddr-format-02.txt: |
| 95 An Extension of Format for IPv6 Scoped Addresses | 103 An Extension of Format for IPv6 Scoped Addresses |
| 104draft-ietf-ngtrans-tcpudp-relay-01.txt: 105 An IPv6-to-IPv4 transport relay translator 106 * FAITH tcp relay translator (faithd) implements this. See 3.1 for more 107 details. 108draft-ietf-ngtrans-6to4-06.txt: 109 Connection of IPv6 Domains via IPv4 Clouds without Explicit Tunnels 110 * "stf" interface implements it. Be sure to read the next item before 111 configuring it, there are security issues. 112http://playground.iijlab.net/i-d/draft-itojun-ipv6-transition-abuse-00.txt: 113 Possible abuse against IPv6 transition technologies 114 * KAME does not implement RFC1933 automatic tunnel. 115 * "stf" interface implements some address filters. Refer to stf(4) 116 for details. Since there's no way to make 6to4 interface 100% secure, 117 we do not include "stf" interface into GENERIC.v6 compilation. 118 * kame/openbsd completely disables IPv4 mapped address support. 119 * kame/netbsd makes IPv4 mapped address support off by default. 120 * See section 12.6 and 14 for more details. |
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| 96 971.2 Neighbor Discovery 98 99Neighbor Discovery is fairly stable. Currently Address Resolution, 100Duplicated Address Detection, and Neighbor Unreachability Detection | 121 1221.2 Neighbor Discovery 123 124Neighbor Discovery is fairly stable. Currently Address Resolution, 125Duplicated Address Detection, and Neighbor Unreachability Detection |
| 101are supported. In the near future we will be adding Proxy Neighbor 102Advertisement support in the kernel and Unsolicited Neighbor Advertisement 103transmission command as admin tool. | 126are supported. In the near future we will be adding Unsolicited Neighbor 127Advertisement transmission command as admin tool. |
| 104 | 128 |
| 129Duplicated Address Detection (DAD) will be performed when an IPv6 address 130is assigned to a network interface, or the network interface is enabled 131(ifconfig up). It is documented in RFC2462 5.4. |
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| 105If DAD fails, the address will be marked "duplicated" and message will be 106generated to syslog (and usually to console). The "duplicated" mark 107can be checked with ifconfig. It is administrators' responsibility to check | 132If DAD fails, the address will be marked "duplicated" and message will be 133generated to syslog (and usually to console). The "duplicated" mark 134can be checked with ifconfig. It is administrators' responsibility to check |
| 108for and recover from DAD failures. 109The behavior should be improved in the near future. | 135for and recover from DAD failures. We may try to improve failure recovery 136in future KAME code. 137DAD procedure may not be effective on certain network interfaces/drivers. 138If a network driver needs long initialization time (with wireless network 139interfaces this situation is popular), and the driver mistakingly raises 140IFF_RUNNING before the driver becomes ready, DAD code will try to transmit 141DAD probes to not-really-ready network driver and the packet will not go out 142from the interface. In such cases, network drivers should be corrected. |
| 110 | 143 |
| 111Some of the network driver loops multicast packets back to itself, | 144Some of network drivers loop multicast packets back to themselves, |
| 112even if instructed not to do so (especially in promiscuous mode). 113In such cases DAD may fail, because DAD engine sees inbound NS packet 114(actually from the node itself) and considers it as a sign of duplicate. 115You may want to look at #if condition marked "heuristics" in 116sys/netinet6/nd6_nbr.c:nd6_dad_timer() as workaround (note that the code 117fragment in "heuristics" section is not spec conformant). 118 119Neighbor Discovery specification (RFC2461) does not talk about neighbor 120cache handling in the following cases: 121(1) when there was no neighbor cache entry, node received unsolicited 122 RS/NS/NA/redirect packet without link-layer address 123(2) neighbor cache handling on medium without link-layer address 124 (we need a neighbor cache entry for IsRouter bit) 125For (1), we implemented workaround based on discussions on IETF ipngwg mailing 126list. For more details, see the comments in the source code and email 127thread started from (IPng 7155), dated Feb 6 1999. 128 129IPv6 on-link determination rule (RFC2461) is quite different from assumptions | 145even if instructed not to do so (especially in promiscuous mode). 146In such cases DAD may fail, because DAD engine sees inbound NS packet 147(actually from the node itself) and considers it as a sign of duplicate. 148You may want to look at #if condition marked "heuristics" in 149sys/netinet6/nd6_nbr.c:nd6_dad_timer() as workaround (note that the code 150fragment in "heuristics" section is not spec conformant). 151 152Neighbor Discovery specification (RFC2461) does not talk about neighbor 153cache handling in the following cases: 154(1) when there was no neighbor cache entry, node received unsolicited 155 RS/NS/NA/redirect packet without link-layer address 156(2) neighbor cache handling on medium without link-layer address 157 (we need a neighbor cache entry for IsRouter bit) 158For (1), we implemented workaround based on discussions on IETF ipngwg mailing 159list. For more details, see the comments in the source code and email 160thread started from (IPng 7155), dated Feb 6 1999. 161 162IPv6 on-link determination rule (RFC2461) is quite different from assumptions |
| 130in BSD network code. At this moment, KAME does not implement on-link 131determination rule when default router list is empty (RFC2461, section 5.2, 132last sentence in 2nd paragraph - note that the spec misuse the word "host" 133and "node" in several places in the section). | 163in BSD IPv4 network code. To implement behavior in RFC2461 section 5.2 164(when default router list is empty), the kernel needs to know the default 165outgoing interface. To configure the default outgoing interface, use 166commands like "ndp -I de0" as root. Note that the spec misuse the word 167"host" and "node" in several places in the section. |
| 134 135To avoid possible DoS attacks and infinite loops, KAME stack will accept 136only 10 options on ND packet. Therefore, if you have 20 prefix options 137attached to RA, only the first 10 prefixes will be recognized. 138If this troubles you, please contact KAME team and/or modify 139nd6_maxndopt in sys/netinet6/nd6.c. If there are high demands we may 140provide sysctl knob for the variable. 141 | 168 169To avoid possible DoS attacks and infinite loops, KAME stack will accept 170only 10 options on ND packet. Therefore, if you have 20 prefix options 171attached to RA, only the first 10 prefixes will be recognized. 172If this troubles you, please contact KAME team and/or modify 173nd6_maxndopt in sys/netinet6/nd6.c. If there are high demands we may 174provide sysctl knob for the variable. 175 |
| 176Proxy Neighbor Advertisement support is implemented in the kernel. 177For instance, you can configure it by using the following command: 178 # ndp -s fe80::1234%ne0 0:1:2:3:4:5 proxy 179where ne0 is the interface which attaches to the same link as the 180proxy target. 181There are certain limitations, though: 182- It does not send unsolicited multicast NA on configuration. This is MAY 183 behavior in RFC2461. 184- It does not add random delay before transmission of solicited NA. This is 185 SHOULD behavior in RFC2461. 186- We cannot configure proxy NDP for off-link address. The target address for 187 proxying must be link-local address, or must be in prefixes configured to 188 node which does proxy NDP. 189- RFC2461 is unclear about if it is legal for a host to perform proxy ND. 190 We do not prohibit hosts from doing proxy ND, but there will be very limited 191 use in it. 192 193Starting mid March 2000, we support Neighbor Unreachability Detection (NUD) 194on p2p interfaces, including tunnel interfaces (gif). NUD is turned on by 195default. Before March 2000 KAME stack did not perform NUD on p2p interfaces. 196If the change raises any interoperability issues, you can turn off/on NUD 197by per-interface basis. Use "ndp -i interface -nud" to turn it off. 198Consult ndp(8) for details. 199 200RFC2461 specifies upper-layer reachability confirmation hint. Whenever 201upper-layer reachability confirmation hint comes, ND process can use it 202to optimize neighbor discovery process - ND process can omit real ND exchange 203and keep the neighbor cache state in REACHABLE. 204We currently have two sources for hints: (1) setsockopt(IPV6_REACHCONF) 205defined by 2292bis API, and (2) hints from tcp_input. 206It is questionable if they are really trustworthy. For example, a rogue 207userland program can use IPV6_REACHCONF to confuse ND process. Neighbor 208cache is a system-wide information pool, and it is bad to allow single process 209to affect others. Also, tcp_input can be hosed by hijack attempts. It is 210wrong to allow hijack attempts to affect ND process. 211Starting June 2000, ND code has a protection mechanism against incorrect 212upper-layer reachability confirmation. ND code counts subsequent upper-layer 213hints. If the number of hints reaches maximum, ND code will ignore further 214upper-layer hints and run real ND process to confirm reachability to the peer. 215sysctl net.inet6.icmp6.nd6_maxnudhint defines maximum # of subsequent 216upper-layer hints to be accepted. 217(from April 2000 to June 2000, we rejected setsockopt(IPV6_REACHCONF) from 218non-root process - after local discussion, it looks that hints are not 219that trustworthy even if they are from privileged processes) 220 |
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| 1421.3 Scope Index 143 | 2211.3 Scope Index 222 |
| 144IPv6 uses scoped addresses. Therefore, it is very important to | 223IPv6 uses scoped addresses. It is therefore very important to |
| 145specify scope index (interface index for link-local address, or 146site index for site-local address) with an IPv6 address. Without | 224specify scope index (interface index for link-local address, or 225site index for site-local address) with an IPv6 address. Without |
| 147scope index, scoped IPv6 address is ambiguous to the kernel, and 148kernel will not be able to determine the outbound interface for a 149packet. | 226scope index, a scoped IPv6 address is ambiguous to the kernel, and 227the kernel will not be able to determine the outbound interface for a 228packet. KAME code tries to address the issue in several ways. |
| 150 | 229 |
| 151Ordinary userland applications should use advanced API (RFC2292) to 152specify scope index, or interface index. For similar purpose, 153sin6_scope_id member in sockaddr_in6 structure is defined in RFC2553. 154However, the semantics for sin6_scope_id is rather vague. If you 155care about portability of your application, we suggest you to use 156advanced API rather than sin6_scope_id. | 230Site-local address is very vaguely defined in the specs, and both specification 231and KAME code need tons of improvements to enable its actual use. 232For example, it is still very unclear how we define a site, or how we resolve 233hostnames in a site. There are work underway to define behavior of routers 234at site border, however, we have almost no code for site boundary node support 235(both forwarding nor routing) and we bet almost noone has. 236We recommend, at this moment, you to use global addresses for experiments - 237there are way too many pitfalls if you use site-local addresses. |
| 157 | 238 |
| 158In the kernel, an interface index for link-local scoped address is 159embedded into 2nd 16bit-word (3rd and 4th byte) in IPv6 address. | 2391.3.1 Kernel internal 240 241In the kernel, the interface index for a link-local scope address is 242embedded into the 2nd 16bit-word (the 3rd and 4th bytes) in the IPv6 243address. |
| 160For example, you may see something like: 161 fe80:1::200:f8ff:fe01:6317 162in the routing table and interface address structure (struct | 244For example, you may see something like: 245 fe80:1::200:f8ff:fe01:6317 246in the routing table and interface address structure (struct |
| 163in6_ifaddr). The address above is a link-local unicast address | 247in6_ifaddr). The address above is a link-local unicast address |
| 164which belongs to a network interface whose interface identifier is 1. 165The embedded index enables us to identify IPv6 link local 166addresses over multiple interfaces effectively and with only a 167little code change. | 248which belongs to a network interface whose interface identifier is 1. 249The embedded index enables us to identify IPv6 link local 250addresses over multiple interfaces effectively and with only a 251little code change. |
| 252 2531.3.2 Interaction with API 254 255Ordinary userland applications should use the advanced API (RFC2292) 256to specify scope index, or interface index. For the similar purpose, 257the sin6_scope_id member in the sockaddr_in6 structure is defined in 258RFC2553. However, the semantics for sin6_scope_id is rather vague. 259If you care about portability of your application, we suggest you to 260use the advanced API rather than sin6_scope_id. 261 |
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| 168Routing daemons and configuration programs, like route6d and 169ifconfig, will need to manipulate the "embedded" scope index. 170These programs use routing sockets and ioctls (like SIOCGIFADDR_IN6) 171and the kernel API will return IPv6 addresses with 2nd 16bit-word 172filled in. The APIs are for manipulating kernel internal structure. 173Programs that use these APIs have to be prepared about differences 174in kernels anyway. 175 | 262Routing daemons and configuration programs, like route6d and 263ifconfig, will need to manipulate the "embedded" scope index. 264These programs use routing sockets and ioctls (like SIOCGIFADDR_IN6) 265and the kernel API will return IPv6 addresses with 2nd 16bit-word 266filled in. The APIs are for manipulating kernel internal structure. 267Programs that use these APIs have to be prepared about differences 268in kernels anyway. 269 |
| 176When you specify scoped address to the command line, NEVER write the 177embedded form (such as ff02:1::1 or fe80:2::fedc). This is not supposed 178to work. Always use standard form, like ff02::1 or fe80::fedc, with 179command line option for specifying interface (like "ping6 -I ne0 ff02::1). 180In general, if a command does not have command line option to specify 181outgoing interface, that command is not ready to accept scoped address. 182This may seem to be opposite from IPv6's premise to support "dentist office" 183situation. We believe that specifications need some improvements for this. 184 185Some of the userland tools support extended numeric IPv6 syntax, as 186documented in draft-ietf-ipngwg-scopedaddr-format-00.txt. You can specify 187outgoing link, by using name of the outgoing interface like "fe80::1%ne0". 188This way you will be able to specify link-local scoped address without much 189trouble. | 270getaddrinfo(3) and getnameinfo(3) are modified to support extended numeric 271IPv6 syntax, as documented in draft-ietf-ipngwg-scopedaddr-format-xx.txt. 272You can specify outgoing link, by using name of the outgoing interface 273like "fe80::1%ne0". This way you will be able to specify link-local scoped 274address without much trouble. |
| 190To use this extension in your program, you'll need to use getaddrinfo(3), 191and getnameinfo(3) with NI_WITHSCOPEID. 192The implementation currently assumes 1-to-1 relationship between a link and an | 275To use this extension in your program, you'll need to use getaddrinfo(3), 276and getnameinfo(3) with NI_WITHSCOPEID. 277The implementation currently assumes 1-to-1 relationship between a link and an |
| 193interface, which is stronger than what specs say. | 278interface, which is stronger than what IPv6 specs say. 279Other APIs like inet_pton(3) or getipnodebyname(3) are inherently unfriendly 280with scoped addresses, since they are unable to annotate addresses with 281scope identifier. |
| 194 | 282 |
| 2831.3.3 Interaction with users (command line) 284 285Most of user applications now support an extended numeric IPv6 syntax, 286as documented in draft-ietf-ipngwg-scopedaddr-format-xx.txt. In this 287case, you can specify outgoing link, by using the name of the outgoing 288interface like "fe80::1%ne0". This is the case for some management 289tools such as route(8) or ndp(8). For example, to install the IPv6 290default route by hand, you can type like 291 # route add -inet6 default fe80::9876:5432:1234:abcd%ne0 292(Although we suggest you to run dynamic routing instead of static 293routes, in order to avoid configuration mistakes.) 294 295Some applications have command line options for specifying an 296appropriate zone of a scoped address (like "ping6 -I ne0 ff02::1" to 297specify the outgoing interface). However, you can't always expect such 298options. Thus, we recommend you to use the extended format described 299above. 300 301In any case, when you specify a scoped address to the command line, 302NEVER write the embedded form (such as ff02:1::1 or fe80:2::fedc), 303which should only be used inside the kernel (see Section 1.3.1), and 304is not supposed to work. 305 |
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| 1951.4 Plug and Play 196 197The KAME kit implements most of the IPv6 stateless address 198autoconfiguration in the kernel. 199Neighbor Discovery functions are implemented in the kernel as a whole. 200Router Advertisement (RA) input for hosts is implemented in the 201kernel. Router Solicitation (RS) output for endhosts, RS input 202for routers, and RA output for routers are implemented in the 203userland. 204 2051.4.1 Assignment of link-local, and special addresses 206 | 3061.4 Plug and Play 307 308The KAME kit implements most of the IPv6 stateless address 309autoconfiguration in the kernel. 310Neighbor Discovery functions are implemented in the kernel as a whole. 311Router Advertisement (RA) input for hosts is implemented in the 312kernel. Router Solicitation (RS) output for endhosts, RS input 313for routers, and RA output for routers are implemented in the 314userland. 315 3161.4.1 Assignment of link-local, and special addresses 317 |
| 207IPv6 link-local address is generated from IEEE802 adddress (ethernet MAC | 318IPv6 link-local address is generated from IEEE802 address (ethernet MAC |
| 208address). Each of interface is assigned an IPv6 link-local address 209automatically, when the interface becomes up (IFF_UP). Also, direct route 210for the link-local address is added to routing table. 211 212Here is an output of netstat command: 213 214Internet6: 215Destination Gateway Flags Netif Expire | 319address). Each of interface is assigned an IPv6 link-local address 320automatically, when the interface becomes up (IFF_UP). Also, direct route 321for the link-local address is added to routing table. 322 323Here is an output of netstat command: 324 325Internet6: 326Destination Gateway Flags Netif Expire |
| 216fe80:1::%ed0/64 link#1 UC ed0 217fe80:2::%ep0/64 link#2 UC ep0 | 327fe80::%ed0/64 link#1 UC ed0 328fe80::%ep0/64 link#2 UC ep0 |
| 218 219Interfaces that has no IEEE802 address (pseudo interfaces like tunnel 220interfaces, or ppp interfaces) will borrow IEEE802 address from other 221interfaces, such as ethernet interfaces, whenever possible. 222If there is no IEEE802 hardware attached, last-resort pseudorandom value, 223which is from MD5(hostname), will be used as source of link-local address. 224If it is not suitable for your usage, you will need to configure the 225link-local address manually. --- 10 unchanged lines hidden (view full) --- 236automatically added to routing table, and loopback interface joins 237node-local multicast group ff01::1. 238 2391.4.2 Stateless address autoconfiguration on hosts 240 241In IPv6 specification, nodes are separated into two categories: 242routers and hosts. Routers forward packets addressed to others, hosts does 243not forward the packets. net.inet6.ip6.forwarding defines whether this | 329 330Interfaces that has no IEEE802 address (pseudo interfaces like tunnel 331interfaces, or ppp interfaces) will borrow IEEE802 address from other 332interfaces, such as ethernet interfaces, whenever possible. 333If there is no IEEE802 hardware attached, last-resort pseudorandom value, 334which is from MD5(hostname), will be used as source of link-local address. 335If it is not suitable for your usage, you will need to configure the 336link-local address manually. --- 10 unchanged lines hidden (view full) --- 347automatically added to routing table, and loopback interface joins 348node-local multicast group ff01::1. 349 3501.4.2 Stateless address autoconfiguration on hosts 351 352In IPv6 specification, nodes are separated into two categories: 353routers and hosts. Routers forward packets addressed to others, hosts does 354not forward the packets. net.inet6.ip6.forwarding defines whether this |
| 244node is router or host (router if it is 1, host if it is 0). | 355node is a router or a host (router if it is 1, host if it is 0). |
| 245 | 356 |
| 357It is NOT recommended to change net.inet6.ip6.forwarding while the node 358is in operation. IPv6 specification defines behavior for "host" and "router" 359quite differently, and switching from one to another can cause serious 360troubles. It is recommended to configure the variable at bootstrap time only. 361 362The first step in stateless address configuration is Duplicated Address 363Detection (DAD). See 1.2 for more detail on DAD. 364 |
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| 246When a host hears Router Advertisement from the router, a host may 247autoconfigure itself by stateless address autoconfiguration. 248This behavior can be controlled by net.inet6.ip6.accept_rtadv 249(host autoconfigures itself if it is set to 1). 250By autoconfiguration, network address prefix for the receiving interface | 365When a host hears Router Advertisement from the router, a host may 366autoconfigure itself by stateless address autoconfiguration. 367This behavior can be controlled by net.inet6.ip6.accept_rtadv 368(host autoconfigures itself if it is set to 1). 369By autoconfiguration, network address prefix for the receiving interface |
| 251(usually global address prefix) is added. Default route is also configured. 252Routers periodically generate Router Advertisement packets. To request 253an adjacent router to generate RA packet, a host can transmit Router 254Solicitation. To generate a RS packet at any time, use the "rtsol" command. 255"rtsold" daemon is also available. "rtsold" generates Router Solicitation 256whenever necessary, and it works great for nomadic usage (notebooks/laptops). 257If one wishes to ignore Router Advertisements, use sysctl to set 258net.inet6.ip6.accept_rtadv to 0. | 370(usually global address prefix) is added. The default route is also 371configured. |
| 259 | 372 |
| 373Routers periodically generate Router Advertisement packets. To 374request an adjacent router to generate RA packet, a host can transmit 375Router Solicitation. To generate an RS packet at any time, use the 376"rtsol" command. The "rtsold" daemon is also available. "rtsold" 377generates Router Solicitation whenever necessary, and it works great 378for nomadic usage (notebooks/laptops). If one wishes to ignore Router 379Advertisements, use sysctl to set net.inet6.ip6.accept_rtadv to 0. 380 |
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| 260To generate Router Advertisement from a router, use the "rtadvd" daemon. 261 | 381To generate Router Advertisement from a router, use the "rtadvd" daemon. 382 |
| 262Note that, IPv6 specification assumes the following items, and nonconforming 263cases are left unspecified: | 383Note that the IPv6 specification assumes the following items and that 384nonconforming cases are left unspecified: |
| 264- Only hosts will listen to router advertisements 265- Hosts have single network interface (except loopback) | 385- Only hosts will listen to router advertisements 386- Hosts have single network interface (except loopback) |
| 266Therefore, this is unwise to enable net.inet6.ip6.accept_rtadv on routers, | 387This is therefore unwise to enable net.inet6.ip6.accept_rtadv on routers, |
| 267or multi-interface host. A misconfigured node can behave strange 268(KAME code allows nonconforming configuration, for those who would like 269to do some experiments). 270 271To summarize the sysctl knob: 272 accept_rtadv forwarding role of the node 273 --- --- --- 274 0 0 host (to be manually configured) 275 0 1 router 276 1 0 autoconfigured host 277 (spec assumes that host has single | 388or multi-interface host. A misconfigured node can behave strange 389(KAME code allows nonconforming configuration, for those who would like 390to do some experiments). 391 392To summarize the sysctl knob: 393 accept_rtadv forwarding role of the node 394 --- --- --- 395 0 0 host (to be manually configured) 396 0 1 router 397 1 0 autoconfigured host 398 (spec assumes that host has single |
| 278 interface only, autoconfigured host 279 with multiple interface is 280 out-of-scope) | 399 interface only, autoconfigred host with 400 multiple interface is out-of-scope) |
| 281 1 1 invalid, or experimental 282 (out-of-scope of spec) 283 | 401 1 1 invalid, or experimental 402 (out-of-scope of spec) 403 |
| 284RFC2462 has validation rule against incoming RA prefix information option, | 404RFC2462 has validation rules against incoming RA prefix information option, |
| 285in 5.5.3 (e). This is to protect hosts from malicious (or misconfigured) 286routers that advertise very short prefix lifetime. 287There was an update from Jim Bound to ipngwg mailing list (look 288for "(ipng 6712)" in the archive) and KAME implements Jim's update. 289 290See 1.2 in the document for relationship between DAD and autoconfiguration. 291 | 405in 5.5.3 (e). This is to protect hosts from malicious (or misconfigured) 406routers that advertise very short prefix lifetime. 407There was an update from Jim Bound to ipngwg mailing list (look 408for "(ipng 6712)" in the archive) and KAME implements Jim's update. 409 410See 1.2 in the document for relationship between DAD and autoconfiguration. 411 |
| 2921.4.3 DHCPv6 (not yet put into freebsd4.0) | 4121.4.3 DHCPv6 |
| 293 | 413 |
| 294We supply a tiny DHCPv6 server/client in kame/dhcp6. However, the 295implementation is very premature (for example, this does NOT 296implement address lease/release), and it is not in default compilation 297tree. If you want to do some experiment, compile it on your own. | 414We supply a tiny DHCPv6 server/client in kame/dhcp6. However, the 415implementation is premature (for example, this does NOT implement 416address lease/release), and it is not in default compilation tree on 417some platforms. If you want to do some experiment, compile it on your 418own. |
| 298 299DHCPv6 and autoconfiguration also needs more work. "Managed" and "Other" 300bits in RA have no special effect to stateful autoconfiguration procedure 301in DHCPv6 client program ("Managed" bit actually prevents stateless 302autoconfiguration, but no special action will be taken for DHCPv6 client). 303 3041.5 Generic tunnel interface 305 --- 10 unchanged lines hidden (view full) --- 316header (v4 in v4, or v6 in v6) is dangerous. It is very easy to 317configure interfaces and routing tables to perform infinite level 318of tunneling. Please be warned. 319 320gif can be configured to be ECN-friendly. See 4.5 for ECN-friendliness 321of tunnels, and gif(4) manpage for how to configure. 322 323If you would like to configure an IPv4-in-IPv6 tunnel with gif interface, | 419 420DHCPv6 and autoconfiguration also needs more work. "Managed" and "Other" 421bits in RA have no special effect to stateful autoconfiguration procedure 422in DHCPv6 client program ("Managed" bit actually prevents stateless 423autoconfiguration, but no special action will be taken for DHCPv6 client). 424 4251.5 Generic tunnel interface 426 --- 10 unchanged lines hidden (view full) --- 437header (v4 in v4, or v6 in v6) is dangerous. It is very easy to 438configure interfaces and routing tables to perform infinite level 439of tunneling. Please be warned. 440 441gif can be configured to be ECN-friendly. See 4.5 for ECN-friendliness 442of tunnels, and gif(4) manpage for how to configure. 443 444If you would like to configure an IPv4-in-IPv6 tunnel with gif interface, |
| 324read gif(4) carefully. You will need to remove IPv6 link-local address | 445read gif(4) carefully. You may need to remove IPv6 link-local address |
| 325automatically assigned to the gif interface. 326 3271.6 Source Address Selection 328 | 446automatically assigned to the gif interface. 447 4481.6 Source Address Selection 449 |
| 329Source selection of KAME is scope oriented (there are some exceptions - 330see below). For a given destination, a source IPv6 address is selected 331by the following rule: 332 1. If the source address is explicitly specified by the user 333 (e.g. via the advanced API), the specified address is used. 334 2. If there is an address assigned to the outgoing interface 335 (which is usually determined by looking up the routing table) 336 that has the same scope as the destination address, the address 337 is used. 338 This is the most typical case. 339 3. If there is no address that satisfies the above condition, 340 choose a global address assigned to one of the interfaces 341 on the sending node. 342 4. If there is no address that satisfies the above condition, 343 and destination address is site local scope, 344 choose a site local address assigned to one of the interfaces 345 on the sending node. 346 5. If there is no address that satisfies the above condition, 347 choose the address associated with the routing table 348 entry for the destination. 349 This is the last resort, which may cause scope violation. | 450KAME's source address selection takes care of the following 451conditions: 452- address scope 453- prefix matching against the destination 454- outgoing interface 455- whether an address is deprecated |
| 350 | 456 |
| 351For instance, ::1 is selected for ff01::1, fe80:1::200:f8ff:fe01:6317 352for fe80:1::2a0:24ff:feab:839b (note that embedded interface index - 353described in 1.3 - helps us choose the right source address. Those 354embedded indices will not be on the wire). 355If the outgoing interface has multiple address for the scope, 356a source is selected longest match basis (rule 3). Suppose | 457Roughly speaking, the selection policy is as follows: 458- always use an address that belongs to the same scope zone as the 459 destination. 460- addresses that have equal or larger scope than the scope of the 461 destination are preferred. 462- if multiple addresses have the equal scope, one which is longest 463 prefix matching against the destination is preferred. 464- a deprecated address is not used in new communications if an 465 alternate (non-deprecated) address is available and has sufficient 466 scope. 467- if none of above conditions tie-breaks, addresses assigned on the 468 outgoing interface are preferred. 469 470For instance, ::1 is selected for ff01::1, 471fe80::200:f8ff:fe01:6317%ne0 for fe80::2a0:24ff:feab:839b%ne0. 472To see how longest-matching works, suppose that |
| 3573ffe:501:808:1:200:f8ff:fe01:6317 and 3ffe:2001:9:124:200:f8ff:fe01:6317 | 4733ffe:501:808:1:200:f8ff:fe01:6317 and 3ffe:2001:9:124:200:f8ff:fe01:6317 |
| 358are given to the outgoing interface. 3ffe:501:808:1:200:f8ff:fe01:6317 359is chosen as the source for the destination 3ffe:501:800::1. | 474are given on the outgoing interface. Then the former is chosen as the 475source for the destination 3ffe:501:800::1. Note that even if all 476available addresses have smaller scope than the scope of the 477destination, we choose one anyway. For example, if we have link-local 478and site-local addresses only, we choose a site-local addresses for a 479global destination. If the packet is going to break a site boundary, 480the boundary router will return an ICMPv6 destination unreachable 481error with code 2 - beyond scope of source address. |
| 360 | 482 |
| 361Note that the above rule is not documented in the IPv6 spec. It is 362considered "up to implementation" item. | 483The precise desripction of the algorithm is quite complicated. To 484describe the algorithm, we introduce the following notation: 485 486For a given destination D, 487 samescope(D): A set of addresses that have the same scope as D. 488 largerscope(D): A set of addresses that have a larger scope than D. 489 smallerscope(D): A set of addresses that have a smaller scope than D. 490 491For a given set of addresses A, 492 DEP(A): a set of deprecated addresses in A. 493 nonDEP(A): A - DEP(A). 494 495Also, the algorithm assumes that the outgoing interface for the 496destination D is determined. We call the interface "I". 497 498The algorithm is as follows. Selection proceeds step by step as 499described; For example, if an address is selected by item 1, item 2 or 500later are not considered at all. 501 502 0. If there is no address in the same scope zone as D, just give up; 503 the packet will not be sent. 504 1. If nonDEP(samescope(D)) is not empty, 505 choose a longest matching address against D. If more than one 506 address is longest matching, choose arbitrary one provided that 507 an address on I is always preferred. 508 2. If nonDEP(largerscope(D)) is not empty, 509 choose an address that has the smallest scope. If more than one 510 address has the smallest scope, choose arbitrary one provided 511 that an address on I is always preferred. 512 3. If DEP(samescope(D)) is not empty, 513 choose a longest matching address against D. If more than one 514 address is longest matching, choose arbitrary one provided that 515 an address on I is always preferred. 516 4. If DEP(largerscope(D)) is not empty, 517 choose an address that has the smallest scope. If more than one 518 address has the smallest scope, choose arbitrary one provided 519 that an address on I is always preferred. 520 5. if nonDEP(smallerscope(D)) is not empty, 521 choose an address that has the largest scope. If more than one 522 address has the largest scope, choose arbitrary one provided 523 that an address on I is always preferred. 524 6. if DEP(smallerscope(D)) is not empty, 525 choose an address that has the largest scope. If more than one 526 address has the largest scope, choose arbitrary one provided 527 that an address on I is always preferred. 528 529There exists a document about source address selection 530(draft-ietf-ipngwg-default-addr-select-xx.txt). KAME's algorithm 531described above takes a similar approach to the document, but there 532are some differences. See the document for more details. 533 |
| 363There are some cases where we do not use the above rule. One | 534There are some cases where we do not use the above rule. One |
| 364example is connected TCP session, and we use the address kept in tcb 365as the source. | 535example is connected TCP session, and we use the address kept in TCP 536protocol control block (tcb) as the source. |
| 366Another example is source address for Neighbor Advertisement. 367Under the spec (RFC2461 7.2.2) NA's source should be the target 368address of the corresponding NS's target. In this case we follow 369the spec rather than the above longest-match rule. 370 | 537Another example is source address for Neighbor Advertisement. 538Under the spec (RFC2461 7.2.2) NA's source should be the target 539address of the corresponding NS's target. In this case we follow 540the spec rather than the above longest-match rule. 541 |
| 371For new connections (when rule 1 does not apply), deprecated addresses 372(addresses with preferred lifetime = 0) will not be chosen as source address 373if other choises are available. If no other choices are available, 374deprecated address will be used as a last resort. If there are multiple 375choice of deprecated addresses, the above scope rule will be used to choose 376from those deprecated addreses. If you would like to prohibit the use 377of deprecated address for some reason, configure net.inet6.ip6.use_deprecated 378to 0. The issue related to deprecated address is described in RFC2462 5.5.4 379(NOTE: there is some debate underway in IETF ipngwg on how to use | 542If you would like to prohibit the use of deprecated address for some 543reason, configure net.inet6.ip6.use_deprecated to 0. The issue 544related to deprecated address is described in RFC2462 5.5.4 (NOTE: 545there is some debate underway in IETF ipngwg on how to use |
| 380"deprecated" address). 381 3821.7 Jumbo Payload 383 384KAME supports the Jumbo Payload hop-by-hop option used to send IPv6 385packets with payloads longer than 65,535 octets. But since currently 386KAME does not support any physical interface whose MTU is more than 38765,535, such payloads can be seen only on the loopback interface(i.e. 388lo0). 389 390If you want to try jumbo payloads, you first have to reconfigure the 391kernel so that the MTU of the loopback interface is more than 65,535 392bytes; add the following to the kernel configuration file: 393 options "LARGE_LOMTU" #To test jumbo payload 394and recompile the new kernel. 395 396Then you can test jumbo payloads by the ping6 command with -b and -s 397options. The -b option must be specified to enlarge the size of the 398socket buffer and the -s option specifies the length of the packet, | 546"deprecated" address). 547 5481.7 Jumbo Payload 549 550KAME supports the Jumbo Payload hop-by-hop option used to send IPv6 551packets with payloads longer than 65,535 octets. But since currently 552KAME does not support any physical interface whose MTU is more than 55365,535, such payloads can be seen only on the loopback interface(i.e. 554lo0). 555 556If you want to try jumbo payloads, you first have to reconfigure the 557kernel so that the MTU of the loopback interface is more than 65,535 558bytes; add the following to the kernel configuration file: 559 options "LARGE_LOMTU" #To test jumbo payload 560and recompile the new kernel. 561 562Then you can test jumbo payloads by the ping6 command with -b and -s 563options. The -b option must be specified to enlarge the size of the 564socket buffer and the -s option specifies the length of the packet, |
| 399which should be more than 65,535. For example, type as follows; | 565which should be more than 65,535. For example, type as follows; |
| 400 % ping6 -b 70000 -s 68000 ::1 401 402The IPv6 specification requires that the Jumbo Payload option must not 403be used in a packet that carries a fragment header. If this condition 404is broken, an ICMPv6 Parameter Problem message must be sent to the 405sender. KAME kernel follows the specification, but you cannot usually 406see an ICMPv6 error caused by this requirement. 407 --- 19 unchanged lines hidden (view full) --- 427need this. 428 429IPsec does not work on jumbograms. This is due to some specification twists 430in supporting AH with jumbograms (AH header size influences payload length, 431and this makes it real hard to authenticate inbound packet with jumbo payload 432option as well as AH). 433 434There are fundamental issues in *BSD support for jumbograms. We would like to | 566 % ping6 -b 70000 -s 68000 ::1 567 568The IPv6 specification requires that the Jumbo Payload option must not 569be used in a packet that carries a fragment header. If this condition 570is broken, an ICMPv6 Parameter Problem message must be sent to the 571sender. KAME kernel follows the specification, but you cannot usually 572see an ICMPv6 error caused by this requirement. 573 --- 19 unchanged lines hidden (view full) --- 593need this. 594 595IPsec does not work on jumbograms. This is due to some specification twists 596in supporting AH with jumbograms (AH header size influences payload length, 597and this makes it real hard to authenticate inbound packet with jumbo payload 598option as well as AH). 599 600There are fundamental issues in *BSD support for jumbograms. We would like to |
| 435address those, but we need more time to finalize these. To name a few: 436- mbuf pkthdr.len field is typed as "int" in 4.4BSD, so it will not hold | 601address those, but we need more time to finalize the task. To name a few: 602- mbuf pkthdr.len field is typed as "int" in 4.4BSD, so it cannot hold |
| 437 jumbogram with len > 2G on 32bit architecture CPUs. If we would like to 438 support jumbogram properly, the field must be expanded to hold 4G + 439 IPv6 header + link-layer header. Therefore, it must be expanded to at least 440 int64_t (u_int32_t is NOT enough). 441- We mistakingly use "int" to hold packet length in many places. We need | 603 jumbogram with len > 2G on 32bit architecture CPUs. If we would like to 604 support jumbogram properly, the field must be expanded to hold 4G + 605 IPv6 header + link-layer header. Therefore, it must be expanded to at least 606 int64_t (u_int32_t is NOT enough). 607- We mistakingly use "int" to hold packet length in many places. We need |
| 442 to convert them into larger integral type. It needs a great care, as we may | 608 to convert them into larger numeric type. It needs a great care, as we may |
| 443 experience overflow during packet length computation. 444- We mistakingly check for ip6_plen field of IPv6 header for packet payload 445 length in various places. We should be checking mbuf pkthdr.len instead. 446 ip6_input() will perform sanity check on jumbo payload option on input, 447 and we can safely use mbuf pkthdr.len afterwards. | 609 experience overflow during packet length computation. 610- We mistakingly check for ip6_plen field of IPv6 header for packet payload 611 length in various places. We should be checking mbuf pkthdr.len instead. 612 ip6_input() will perform sanity check on jumbo payload option on input, 613 and we can safely use mbuf pkthdr.len afterwards. |
| 448- TCP code needs a careful update in bunch of places, of course. | 614- TCP code needs careful updates in bunch of places, of course. |
| 449 4501.8 Loop prevention in header processing 451 452IPv6 specification allows arbitrary number of extension headers to 453be placed onto packets. If we implement IPv6 packet processing 454code in the way BSD IPv4 code is implemented, kernel stack may 455overflow due to long function call chain. KAME sys/netinet6 code 456is carefully designed to avoid kernel stack overflow. Because of 457this, KAME sys/netinet6 code defines its own protocol switch 458structure, as "struct ip6protosw" (see netinet6/ip6protosw.h). | 615 6161.8 Loop prevention in header processing 617 618IPv6 specification allows arbitrary number of extension headers to 619be placed onto packets. If we implement IPv6 packet processing 620code in the way BSD IPv4 code is implemented, kernel stack may 621overflow due to long function call chain. KAME sys/netinet6 code 622is carefully designed to avoid kernel stack overflow. Because of 623this, KAME sys/netinet6 code defines its own protocol switch 624structure, as "struct ip6protosw" (see netinet6/ip6protosw.h). |
| 459There is no such update to IPv4 part (sys/netinet) for 460compatibility, but small change is added to its pr_input() 461prototype. So "struct ipprotosw" is also defined. | 625IPv4 part (sys/netinet) remains untouched for compatibility. |
| 462Because of this, if you receive IPsec-over-IPv4 packet with massive 463number of IPsec headers, kernel stack may blow up. IPsec-over-IPv6 is okay. | 626Because of this, if you receive IPsec-over-IPv4 packet with massive 627number of IPsec headers, kernel stack may blow up. IPsec-over-IPv6 is okay. |
| 464(Off-course, for those all IPsec headers to be processed, each 465such IPsec header must pass each IPsec check. So an anonymous 466attacker won't be able to do such an attack.) | |
| 467 4681.9 ICMPv6 469 470After RFC2463 was published, IETF ipngwg has decided to disallow ICMPv6 error 471packet against ICMPv6 redirect, to prevent ICMPv6 storm on a network medium. 472KAME already implements this into the kernel. 473 | 628 6291.9 ICMPv6 630 631After RFC2463 was published, IETF ipngwg has decided to disallow ICMPv6 error 632packet against ICMPv6 redirect, to prevent ICMPv6 storm on a network medium. 633KAME already implements this into the kernel. 634 |
| 635RFC2463 requires rate limitation for ICMPv6 error packets generated by a 636node, to avoid possible DoS attacks. KAME kernel implements two rate- 637limitation mechanisms, tunable via sysctl: 638- Minimum time interval between ICMPv6 error packets 639 KAME kernel will generate no more than one ICMPv6 error packet, 640 during configured time interval. net.inet6.icmp6.errratelimit 641 controls the interval (default: disabled). 642- Maximum ICMPv6 error packet-per-second 643 KAME kernel will generate no more than the configured number of 644 packets in one second. net.inet6.icmp6.errppslimit controls the 645 maximum packet-per-second value (default: 200pps) 646Basically, we need to pick values that are suitable against the bandwidth 647of link layer devices directly attached to the node. In some cases the 648default values may not fit well. We are still unsure if the default value 649is sane or not. Comments are welcome. 650 |
|
| 4741.10 Applications 475 476For userland programming, we support IPv6 socket API as specified in 477RFC2553, RFC2292 and upcoming internet drafts. 478 479TCP/UDP over IPv6 is available and quite stable. You can enjoy "telnet", 480"ftp", "rlogin", "rsh", "ssh", etc. These applications are protocol 481independent. That is, they automatically chooses IPv4 or IPv6 --- 6 unchanged lines hidden (view full) --- 488 489The current KAME has escaped from the IPv4 netinet logic. While 490ip_forward() calls ip_output(), ip6_forward() directly calls 491if_output() since routers must not divide IPv6 packets into fragments. 492 493ICMPv6 should contain the original packet as long as possible up to 4941280. UDP6/IP6 port unreach, for instance, should contain all 495extension headers and the *unchanged* UDP6 and IP6 headers. | 6511.10 Applications 652 653For userland programming, we support IPv6 socket API as specified in 654RFC2553, RFC2292 and upcoming internet drafts. 655 656TCP/UDP over IPv6 is available and quite stable. You can enjoy "telnet", 657"ftp", "rlogin", "rsh", "ssh", etc. These applications are protocol 658independent. That is, they automatically chooses IPv4 or IPv6 --- 6 unchanged lines hidden (view full) --- 665 666The current KAME has escaped from the IPv4 netinet logic. While 667ip_forward() calls ip_output(), ip6_forward() directly calls 668if_output() since routers must not divide IPv6 packets into fragments. 669 670ICMPv6 should contain the original packet as long as possible up to 6711280. UDP6/IP6 port unreach, for instance, should contain all 672extension headers and the *unchanged* UDP6 and IP6 headers. |
| 496So, all IP6 functions except TCP never convert network byte | 673So, all IP6 functions except TCP6 never convert network byte |
| 497order into host byte order, to save the original packet. 498 | 674order into host byte order, to save the original packet. 675 |
| 499tcp_input(), udp6_input() and icmp6_input() can't assume that IP6 | 676tcp6_input(), udp6_input() and icmp6_input() can't assume that IP6 |
| 500header is preceding the transport headers due to extension 501headers. So, in6_cksum() was implemented to handle packets whose IP6 | 677header is preceding the transport headers due to extension 678headers. So, in6_cksum() was implemented to handle packets whose IP6 |
| 502header and transport header is not continuous. TCP/IP6 nor UDP6/IP6 | 679header and transport header is not continuous. TCP/IP6 nor UDP/IP6 |
| 503header structure don't exist for checksum calculation. 504 505To process IP6 header, extension headers and transport headers easily, 506KAME requires network drivers to store packets in one internal mbuf or 507one or more external mbufs. A typical old driver prepares two | 680header structure don't exist for checksum calculation. 681 682To process IP6 header, extension headers and transport headers easily, 683KAME requires network drivers to store packets in one internal mbuf or 684one or more external mbufs. A typical old driver prepares two |
| 508internal mbufs for 96 - 204 bytes data, however, KAME's reference | 685internal mbufs for 100 - 208 bytes data, however, KAME's reference |
| 509implementation stores it in one external mbuf. 510 511"netstat -s -p ip6" tells you whether or not your driver conforms 512KAME's requirement. In the following example, "cce0" violates the 513requirement. (For more information, refer to Section 2.) 514 515 Mbuf statistics: 516 317 one mbuf --- 5 unchanged lines hidden (view full) --- 522 523Each input function calls IP6_EXTHDR_CHECK in the beginning to check 524if the region between IP6 and its header is 525continuous. IP6_EXTHDR_CHECK calls m_pullup() only if the mbuf has 526M_LOOP flag, that is, the packet comes from the loopback 527interface. m_pullup() is never called for packets coming from physical 528network interfaces. 529 | 686implementation stores it in one external mbuf. 687 688"netstat -s -p ip6" tells you whether or not your driver conforms 689KAME's requirement. In the following example, "cce0" violates the 690requirement. (For more information, refer to Section 2.) 691 692 Mbuf statistics: 693 317 one mbuf --- 5 unchanged lines hidden (view full) --- 699 700Each input function calls IP6_EXTHDR_CHECK in the beginning to check 701if the region between IP6 and its header is 702continuous. IP6_EXTHDR_CHECK calls m_pullup() only if the mbuf has 703M_LOOP flag, that is, the packet comes from the loopback 704interface. m_pullup() is never called for packets coming from physical 705network interfaces. 706 |
| 530Both IP and IP6 reassemble functions never call m_pullup(). | 707TCP6 reassembly makes use of IP6 header to store reassemble 708information. IP6 is not supposed to be just before TCP6, so 709ip6tcpreass structure has a pointer to TCP6 header. Of course, it has 710also a pointer back to mbuf to avoid m_pullup(). |
| 531 | 711 |
| 712Like TCP6, both IP and IP6 reassemble functions never call m_pullup(). 713 714xxx_ctlinput() calls in_mrejoin() on PRC_IFNEWADDR. We think this is 715one of 4.4BSD implementation flaws. Since 4.4BSD keeps ia_multiaddrs 716in in_ifaddr{}, it can't use multicast feature if the interface has no 717unicast address. So, if an application joins to an interface and then 718all unicast addresses are removed from the interface, the application 719can't send/receive any multicast packets. Moreover, if a new unicast 720address is assigned to the interface, in_mrejoin() must be called. 721KAME's interfaces, however, have ALWAYS one link-local unicast 722address. These extensions have thus not been implemented in KAME. 723 |
|
| 5321.12 IPv4 mapped address and IPv6 wildcard socket 533 534RFC2553 describes IPv4 mapped address (3.7) and special behavior 535of IPv6 wildcard bind socket (3.8). The spec allows you to: 536- Accept IPv4 connections by AF_INET6 wildcard bind socket. 537- Transmit IPv4 packet over AF_INET6 socket by using special form of 538 the address like ::ffff:10.1.1.1. 539but the spec itself is very complicated and does not specify how the 540socket layer should behave. 541Here we call the former one "listening side" and the latter one "initiating 542side", for reference purposes. 543 544Almost all KAME implementations treat tcp/udp port number space separately | 7241.12 IPv4 mapped address and IPv6 wildcard socket 725 726RFC2553 describes IPv4 mapped address (3.7) and special behavior 727of IPv6 wildcard bind socket (3.8). The spec allows you to: 728- Accept IPv4 connections by AF_INET6 wildcard bind socket. 729- Transmit IPv4 packet over AF_INET6 socket by using special form of 730 the address like ::ffff:10.1.1.1. 731but the spec itself is very complicated and does not specify how the 732socket layer should behave. 733Here we call the former one "listening side" and the latter one "initiating 734side", for reference purposes. 735 736Almost all KAME implementations treat tcp/udp port number space separately |
| 545between IPv4 and IPv6. You can perform wildcard bind on both of the adderss | 737between IPv4 and IPv6. You can perform wildcard bind on both of the address |
| 546families, on the same port. 547 | 738families, on the same port. 739 |
| 548The following table show the behavior of FreeBSD4x. | 740There are some OS-platform differences in KAME code, as we use tcp/udp 741code from different origin. The following table summarizes the behavior. |
| 549 550 listening side initiating side | 742 743 listening side initiating side |
| 551 (AF_INET6 wildcard (connetion to ::ffff:10.1.1.1) | 744 (AF_INET6 wildcard (connection to ::ffff:10.1.1.1) |
| 552 socket gets IPv4 conn.) 553 --- --- | 745 socket gets IPv4 conn.) 746 --- --- |
| 554FreeBSD4x configurable supported | 747KAME/BSDI3 not supported not supported 748KAME/FreeBSD228 not supported not supported 749KAME/FreeBSD3x configurable supported |
| 555 default: enabled | 750 default: enabled |
| 751KAME/FreeBSD4x configurable supported 752 default: enabled 753KAME/NetBSD configurable supported 754 default: disabled 755KAME/BSDI4 enabled supported 756KAME/OpenBSD not supported not supported |
|
| 556 557The following sections will give you more details, and how you can 558configure the behavior. 559 560Comments on listening side: 561 562It looks that RFC2553 talks too little on wildcard bind issue, | 757 758The following sections will give you more details, and how you can 759configure the behavior. 760 761Comments on listening side: 762 763It looks that RFC2553 talks too little on wildcard bind issue, |
| 563especially on the port space issue, failure mode and relationship 564between AF_INET/INET6 wildcard bind. There can be several separate | 764specifically on (1) port space issue, (2) failure mode, (3) relationship 765between AF_INET/INET6 wildcard bind like ordering constraint, and (4) behavior 766when conflicting socket is opened/closed. There can be several separate |
| 565interpretation for this RFC which conform to it but behaves differently. 566So, to implement portable application you should assume nothing 567about the behavior in the kernel. Using getaddrinfo() is the safest way. 568Port number space and wildcard bind issues were discussed in detail 569on ipv6imp mailing list, in mid March 1999 and it looks that there's 570no concrete consensus (means, up to implementers). You may want to 571check the mailing list archives. | 767interpretation for this RFC which conform to it but behaves differently. 768So, to implement portable application you should assume nothing 769about the behavior in the kernel. Using getaddrinfo() is the safest way. 770Port number space and wildcard bind issues were discussed in detail 771on ipv6imp mailing list, in mid March 1999 and it looks that there's 772no concrete consensus (means, up to implementers). You may want to 773check the mailing list archives. |
| 774We supply a tool called "bindtest" that explores the behavior of 775kernel bind(2). The tool will not be compiled by default. |
|
| 572 573If a server application would like to accept IPv4 and IPv6 connections, | 776 777If a server application would like to accept IPv4 and IPv6 connections, |
| 574there will be two alternatives. 575 576One is using AF_INET and AF_INET6 socket (you'll need two sockets). | 778it should use AF_INET and AF_INET6 socket (you'll need two sockets). |
| 577Use getaddrinfo() with AI_PASSIVE into ai_flags, and socket(2) and bind(2) 578to all the addresses returned. 579By opening multiple sockets, you can accept connections onto the socket with 580proper address family. IPv4 connections will be accepted by AF_INET socket, | 779Use getaddrinfo() with AI_PASSIVE into ai_flags, and socket(2) and bind(2) 780to all the addresses returned. 781By opening multiple sockets, you can accept connections onto the socket with 782proper address family. IPv4 connections will be accepted by AF_INET socket, |
| 581and IPv6 connections will be accepted by AF_INET6 socket. | 783and IPv6 connections will be accepted by AF_INET6 socket (NOTE: KAME/BSDI4 784kernel sometimes violate this - we will fix it). |
| 582 | 785 |
| 583Another way is using one AF_INET6 wildcard bind socket. 584Use getaddrinfo() with AI_PASSIVE into ai_flags and with 585AF_INET6 into ai_family, and set the 1st argument hostname to 586NULL. And socket(2) and bind(2) to the address returned. 587(should be IPv6 unspecified addr) 588You can accept either of IPv4 and IPv6 packet via this one socket. 589 590To support only IPv6 traffic on AF_INET6 wildcard binded socket portably, 591always check the peer address when a connection is made toward | 786If you try to support IPv6 traffic only and would like to reject IPv4 787traffic, always check the peer address when a connection is made toward |
| 592AF_INET6 listening socket. If the address is IPv4 mapped address, you may 593want to reject the connection. You can check the condition by using | 788AF_INET6 listening socket. If the address is IPv4 mapped address, you may 789want to reject the connection. You can check the condition by using |
| 594IN6_IS_ADDR_V4MAPPED() macro. 595To resolv this issue more easily, there is system dependent setsockopt() 596option, IPV6_BINDV6ONLY, used like below. 597 int on; | 790IN6_IS_ADDR_V4MAPPED() macro. This is one of the reasons the author of 791the section (itojun) dislikes special behavior of AF_INET6 wildcard bind. |
| 598 | 792 |
| 599 setsockopt(s, IPPROTO_IPV6, IPV6_BINDV6ONLY, 600 (char *)&on, sizeof (on)) < 0)); 601When this call succeed, then this socket only receive IPv6 packets. 602 603 | |
| 604Comments on initiating side: 605 606Advise to application implementers: to implement a portable IPv6 application 607(which works on multiple IPv6 kernels), we believe that the following 608is the key to the success: 609- NEVER hardcode AF_INET nor AF_INET6. 610- Use getaddrinfo() and getnameinfo() throughout the system. 611 Never use gethostby*(), getaddrby*(), inet_*() or getipnodeby*(). | 793Comments on initiating side: 794 795Advise to application implementers: to implement a portable IPv6 application 796(which works on multiple IPv6 kernels), we believe that the following 797is the key to the success: 798- NEVER hardcode AF_INET nor AF_INET6. 799- Use getaddrinfo() and getnameinfo() throughout the system. 800 Never use gethostby*(), getaddrby*(), inet_*() or getipnodeby*(). |
| 612 (To update existing applications to be IPv6 aware easily, 613 sometime getipnodeby*() will be useful. But if possible, try to 614 rewrite the code to use getaddrinfo() and getnameinfo().) | |
| 615- If you would like to connect to destination, use getaddrinfo() and try 616 all the destination returned, like telnet does. 617- Some of the IPv6 stack is shipped with buggy getaddrinfo(). Ship a minimal 618 working version with your application and use that as last resort. 619 620If you would like to use AF_INET6 socket for both IPv4 and IPv6 outgoing | 801- If you would like to connect to destination, use getaddrinfo() and try 802 all the destination returned, like telnet does. 803- Some of the IPv6 stack is shipped with buggy getaddrinfo(). Ship a minimal 804 working version with your application and use that as last resort. 805 806If you would like to use AF_INET6 socket for both IPv4 and IPv6 outgoing |
| 621connection, you will need to use getipnodebyname(). When you would like to 622update your existing appication to be IPv6 aware with minimal effort, 623this approach might be choosed. But please note that it is a temporal 624solution, because getipnodebyname() itself is not recommended as it does 625not handle scoped IPv6 addresses at all. For IPv6 name resolution, 626getaddrinfo() is the preferred API. So you should rewrite your 627application to use getaddrinfo(), when you get the time to do it. | 807connection, you will need tweaked implementation in DNS support libraries, 808as documented in RFC2553 6.1. KAME libinet6 includes the tweak in 809getipnodebyname(). Note that getipnodebyname() itself is not recommended as 810it does not handle scoped IPv6 addresses at all. For IPv6 name resolution 811getaddrinfo() is the preferred API. getaddrinfo() does not implement the 812tweak. |
| 628 629When writing applications that make outgoing connections, story goes much | 813 814When writing applications that make outgoing connections, story goes much |
| 630simpler if you treat AF_INET and AF_INET6 as totally seaprate address family. | 815simpler if you treat AF_INET and AF_INET6 as totally separate address family. |
| 631{set,get}sockopt issue goes simpler, DNS issue will be made simpler. We do 632not recommend you to rely upon IPv4 mapped address. 633 | 816{set,get}sockopt issue goes simpler, DNS issue will be made simpler. We do 817not recommend you to rely upon IPv4 mapped address. 818 |
| 6341.12.1 FreeBSD4x | 8191.12.1 KAME/BSDI3 and KAME/FreeBSD228 |
| 635 | 820 |
| 636FreeBSD4x uses shared tcp4/6 code (from sys/netinet/tcp*) and separete 637udp4/6 code. It uses unified inpcb/in6pcb structure. | 821The platforms do not support IPv4 mapped address at all (both listening side 822and initiating side). AF_INET6 and AF_INET sockets are totally separated. |
| 638 | 823 |
| 639The platform can be configured to support IPv4 mapped address. 640Kernel configuration is summarized as follows: 641- By default, AF_INET6 socket will grab IPv4 connections in certain condition, 642 and can initiate connection to IPv4 destination embedded in 643 IPv4 mapped IPv6 address. 644- You can disable it on entire system with sysctl like below. 645 sysctl -w net.inet6.ip6.mapped_addr=0 | 824Port number space is totally separate between AF_INET and AF_INET6 sockets. |
| 646 | 825 |
| 6471.12.1.1 FreeBSD4x, listening side | 8261.12.2 KAME/FreeBSD[34]x |
| 648 | 827 |
| 649Each socket can be configured to support special AF_INET6 wildcard bind 650(enabled by default). 651You can disable it on each socket basis with setsockopt() like below. 652 int on; | 828KAME/FreeBSD3x and KAME/FreeBSD4x use shared tcp4/6 code (from 829sys/netinet/tcp*) and shared udp4/6 code (from sys/netinet/udp*). 830They use unified inpcb/in6pcb structure. |
| 653 | 831 |
| 654 setsockopt(s, IPPROTO_IPV6, IPV6_BINDV6ONLY, 655 (char *)&on, sizeof (on)) < 0)); | 8321.12.2.1 KAME/FreeBSD[34]x, listening side |
| 656 | 833 |
| 657Wildcard AF_INET6 socket grabs IPv4 connection if and only if the following | 834The platform can be configured to support IPv4 mapped address/special 835AF_INET6 wildcard bind (enabled by default). There is no kernel compilation 836option to disable it. You can enable/disable the behavior with sysctl 837(per-node), or setsockopt (per-socket). 838 839Wildcard AF_INET6 socket grabs IPv4 connection if and only if the following |
| 658conditions are satisfied: 659- there's no AF_INET socket that matches the IPv4 connection 660- the AF_INET6 socket is configured to accept IPv4 traffic, i.e. 661 getsockopt(IPV6_BINDV6ONLY) returns 0. | 840conditions are satisfied: 841- there's no AF_INET socket that matches the IPv4 connection 842- the AF_INET6 socket is configured to accept IPv4 traffic, i.e. 843 getsockopt(IPV6_BINDV6ONLY) returns 0. |
| 662There's no problem with open/close ordering. | |
| 663 | 844 |
| 6641.12.1.2 FreeBSD4x, initiating side | 845(XXX need checking) |
| 665 | 846 |
| 666FreeBSD4x supports outgoing connetion to IPv4 mapped address 667(::ffff:10.1.1.1), if the node is configured to support IPv4 mapped address. | 8471.12.2.2 KAME/FreeBSD[34]x, initiating side |
| 668 | 848 |
| 849KAME/FreeBSD3x supports outgoing connection to IPv4 mapped address 850(::ffff:10.1.1.1), if the node is configured to accept IPv4 connections 851by AF_INET6 socket. 852 853(XXX need checking) 854 8551.12.3 KAME/NetBSD 856 857KAME/NetBSD uses shared tcp4/6 code (from sys/netinet/tcp*) and shared 858udp4/6 code (from sys/netinet/udp*). The implementation is made differently 859from KAME/FreeBSD[34]x. KAME/NetBSD uses separate inpcb/in6pcb structures, 860while KAME/FreeBSD[34]x uses merged inpcb structure. 861 8621.12.3.1 KAME/NetBSD, listening side 863 864The platform can be configured to support IPv4 mapped address/special AF_INET6 865wildcard bind (disabled by default). Kernel behavior can be summarized as 866follows: 867- default: special support code will be compiled in, but is disabled by 868 default. It can be controlled by sysctl (net.inet6.ip6.bindv6only), 869 or setsockopt(IPV6_BINDV6ONLY). 870- add "INET6_BINDV6ONLY": No special support code for AF_INET6 wildcard socket 871 will be compiled in. AF_INET6 sockets and AF_INET sockets are totally 872 separate. The behavior is similar to what described in 1.12.1. 873 874sysctl setting will affect per-socket configuration at in6pcb creation time 875only. In other words, per-socket configuration will be copied from sysctl 876configuration at in6pcb creation time. To change per-socket behavior, you 877must perform setsockopt or reopen the socket. Change in sysctl configuration 878will not change the behavior or sockets that are already opened. 879 880Wildcard AF_INET6 socket grabs IPv4 connection if and only if the following 881conditions are satisfied: 882- there's no AF_INET socket that matches the IPv4 connection 883- the AF_INET6 socket is configured to accept IPv4 traffic, i.e. 884 getsockopt(IPV6_BINDV6ONLY) returns 0. 885 886You cannot bind(2) with IPv4 mapped address. This is a workaround for port 887number duplicate and other twists. 888 8891.12.3.2 KAME/NetBSD, initiating side 890 891When you initiate a connection, you can always connect to IPv4 destination 892over AF_INET6 socket, usin IPv4 mapped address destination (::ffff:10.1.1.1). 893This is enabled independently from the configuration for listening side, and 894always enabled. 895 8961.12.4 KAME/BSDI4 897 898KAME/BSDI4 uses NRL-based TCP/UDP stack and inpcb source code, 899which was derived from NRL IPv6/IPsec stack. We guess it supports IPv4 mapped 900address and speical AF_INET6 wildcard bind. The implementation is, again, 901different from other KAME/*BSDs. 902 9031.12.4.1 KAME/BSDI4, listening side 904 905NRL inpcb layer supports special behavior of AF_INET6 wildcard socket. 906There is no way to disable the behavior. 907 908Wildcard AF_INET6 socket grabs IPv4 connection if and only if the following 909condition is satisfied: 910- there's no AF_INET socket that matches the IPv4 connection 911 9121.12.4.2 KAME/BSDI4, initiating side 913 914KAME/BSDi4 supports connection initiation to IPv4 mapped address 915(like ::ffff:10.1.1.1). 916 9171.12.5 KAME/OpenBSD 918 919KAME/OpenBSD uses NRL-based TCP/UDP stack and inpcb source code, 920which was derived from NRL IPv6/IPsec stack. 921 9221.12.5.1 KAME/OpenBSD, listening side 923 924KAME/OpenBSD disables special behavior on AF_INET6 wildcard bind for 925security reasons (if IPv4 traffic toward AF_INET6 wildcard bind is allowed, 926access control will become much harder). KAME/BSDI4 uses NRL-based TCP/UDP 927stack as well, however, the behavior is different due to OpenBSD's security 928policy. 929 930As a result the behavior of KAME/OpenBSD is similar to KAME/BSDI3 and 931KAME/FreeBSD228 (see 1.12.1 for more detail). 932 9331.12.5.2 KAME/OpenBSD, initiating side 934 935KAME/OpenBSD does not support connection initiation to IPv4 mapped address 936(like ::ffff:10.1.1.1). 937 9381.12.6 More issues 939 940IPv4 mapped address support adds a big requirement to EVERY userland codebase. 941Every userland code should check if an AF_INET6 sockaddr contains IPv4 942mapped address or not. This adds many twists: 943 944- Access controls code becomes harder to write. 945 For example, if you would like to reject packets from 10.0.0.0/8, 946 you need to reject packets to AF_INET socket from 10.0.0.0/8, 947 and to AF_INET6 socket from ::ffff:10.0.0.0/104. 948- If a protocol on top of IPv4 is defined differently with IPv6, we need to be 949 really careful when we determine which protocol to use. 950 For example, with FTP protocol, we can not simply use sa_family to determine 951 FTP command sets. The following example is incorrect: 952 if (sa_family == AF_INET) 953 use EPSV/EPRT or PASV/PORT; /*IPv4*/ 954 else if (sa_family == AF_INET6) 955 use EPSV/EPRT or LPSV/LPRT; /*IPv6*/ 956 else 957 error; 958 Under SIIT environment, the correct code would be: 959 if (sa_family == AF_INET) 960 use EPSV/EPRT or PASV/PORT; /*IPv4*/ 961 else if (sa_family == AF_INET6 && IPv4 mapped address) 962 use EPSV/EPRT or PASV/PORT; /*IPv4 command set on AF_INET6*/ 963 else if (sa_family == AF_INET6 && !IPv4 mapped address) 964 use EPSV/EPRT or LPSV/LPRT; /*IPv6*/ 965 else 966 error; 967 It is too much to ask for every body to be careful like this. 968 The problem is, we are not sure if the above code fragment is perfect for 969 all situations. 970- By enabling kernel support for IPv4 mapped address (outgoing direction), 971 servers on the kernel can be hosed by IPv6 native packet that has IPv4 972 mapped address in IPv6 header source, and can generate unwanted IPv4 packets. 973 http://playground.iijlab.net/i-d/draft-itojun-ipv6-transition-abuse-00.txt 974 talks more about this scenario. 975 976Due to the above twists, some of KAME userland programs has restrictions on 977the use of IPv4 mapped addresses: 978- rshd/rlogind do not accept connections from IPv4 mapped address. 979 This is to avoid malicious use of IPv4 mapped address in IPv6 native 980 packet, to bypass source-address based authentication. 981- ftp/ftpd does not support SIIT environment. IPv4 mapped address will be 982 decoded in userland, and will be passed to AF_INET sockets 983 (SIIT client should pass IPv4 mapped address as is, to AF_INET6 sockets). 984 |
|
| 6691.13 sockaddr_storage 670 | 9851.13 sockaddr_storage 986 |
| 671When RFC2553 was about to be finalized, there was discusson on how struct | 987When RFC2553 was about to be finalized, there was discussion on how struct |
| 672sockaddr_storage members are named. One proposal is to prepend "__" to the 673members (like "__ss_len") as they should not be touched. The other proposal 674was that don't prepend it (like "ss_len") as we need to touch those members 675directly. There was no clear consensus on it. 676 677As a result, RFC2553 defines struct sockaddr_storage as follows: 678 struct sockaddr_storage { 679 u_char __ss_len; /* address length */ --- 7 unchanged lines hidden (view full) --- 687 /* and bunch of padding */ 688 }; 689 690In December 1999, it was agreed that RFC2553bis should pick the latter (XNET) 691definition. 692 693KAME kit prior to December 1999 used RFC2553 definition. KAME kit after 694December 1999 (including December) will conform to XNET definition, | 988sockaddr_storage members are named. One proposal is to prepend "__" to the 989members (like "__ss_len") as they should not be touched. The other proposal 990was that don't prepend it (like "ss_len") as we need to touch those members 991directly. There was no clear consensus on it. 992 993As a result, RFC2553 defines struct sockaddr_storage as follows: 994 struct sockaddr_storage { 995 u_char __ss_len; /* address length */ --- 7 unchanged lines hidden (view full) --- 1003 /* and bunch of padding */ 1004 }; 1005 1006In December 1999, it was agreed that RFC2553bis should pick the latter (XNET) 1007definition. 1008 1009KAME kit prior to December 1999 used RFC2553 definition. KAME kit after 1010December 1999 (including December) will conform to XNET definition, |
| 695based on RFC2553bis discusson. | 1011based on RFC2553bis discussion. |
| 696 697If you look at multiple IPv6 implementations, you will be able to see 698both definitions. As an userland programmer, the most portable way of 699dealing with it is to: 700(1) ensure ss_family and/or ss_len are available on the platform, by using 701 GNU autoconf, 702(2) have -Dss_family=__ss_family to unify all occurences (including header 703 file) into __ss_family, or 704(3) never touch __ss_family. cast to sockaddr * and use sa_family like: 705 struct sockaddr_storage ss; 706 family = ((struct sockaddr *)&ss)->sa_family 707 | 1012 1013If you look at multiple IPv6 implementations, you will be able to see 1014both definitions. As an userland programmer, the most portable way of 1015dealing with it is to: 1016(1) ensure ss_family and/or ss_len are available on the platform, by using 1017 GNU autoconf, 1018(2) have -Dss_family=__ss_family to unify all occurences (including header 1019 file) into __ss_family, or 1020(3) never touch __ss_family. cast to sockaddr * and use sa_family like: 1021 struct sockaddr_storage ss; 1022 family = ((struct sockaddr *)&ss)->sa_family 1023 |
| 10241.14 Invalid addresses on the wire 1025 1026Some of IPv6 transition technologies embed IPv4 address into IPv6 address. 1027These specifications themselves are fine, however, there can be certain 1028set of attacks enabled by these specifications. Recent speicifcation 1029documents covers up those issues, however, there are already-published RFCs 1030that does not have protection against those (like using source address of 1031::ffff:127.0.0.1 to bypass "reject packet from remote" filter). 1032 1033To name a few, these address ranges can be used to hose an IPv6 implementation, 1034or bypass security controls: 1035- IPv4 mapped address that embeds unspecified/multicast/loopback/broadcast 1036 IPv4 address (if they are in IPv6 native packet header, they are malicious) 1037 ::ffff:0.0.0.0/104 ::ffff:127.0.0.0/104 1038 ::ffff:224.0.0.0/100 ::ffff:255.0.0.0/104 1039- 6to4 prefix generated from unspecified/multicast/loopback/broadcast/private 1040 IPv4 address 1041 2002:0000::/24 2002:7f00::/24 2002:e000::/24 1042 2002:ff00::/24 2002:0a00::/24 2002:ac10::/28 1043 2002:c0a8::/32 1044 1045Also, since KAME does not support RFC1933 auto tunnels, seeing IPv4 compatible 1046is very rare. You should take caution if you see those on the wire. 1047 1048KAME code is carefully written to avoid such incidents. More specifically, 1049KAME kernel will reject packets with certain source/dstination address in IPv6 1050base header, or IPv6 routing header. Also, KAME default configuration file 1051is written carefully, to avoid those attacks. 1052 1053http://playground.iijlab.net/i-d/draft-itojun-ipv6-transition-abuse-00.txt 1054talks about more about this. 1055 10561.15 Node's required addresses 1057 1058RFC2373 section 2.8 talks about required addresses for an IPv6 1059node. The section talks about how KAME stack manages those required 1060addresses. 1061 10621.15.1 Host case 1063 1064The following items are automatically assigned to the node (or the node will 1065automatically joins the group), at bootstrap time: 1066- Loopback address 1067- All-nodes multicast addresses (ff01::1) 1068 1069The following items will be automatically handled when the interface becomes 1070IFF_UP: 1071- Its link-local address for each interface 1072- Solicited-node multicast address for link-local addresses 1073- Link-local allnodes multicast address (ff02::1) 1074 1075The following items need to be configured manually by ifconfig(8) or prefix(8). 1076Alternatively, these can be autoconfigured by using stateless address 1077autoconfiguration. 1078- Assigned unicast/anycast addresses 1079- Solicited-Node multicast address for assigned unicast address 1080 1081Users can join groups by using appropriate system calls like setsockopt(2). 1082 10831.15.2 Router case 1084 1085In addition to the above, routers needs to handle the following items. 1086 1087The following items need to be configured manually by using ifconfig(8). 1088o The subnet-router anycast addresses for the interfaces it is configured 1089 to act as a router on (prefix::/64) 1090o All other anycast addresses with which the router has been configured 1091 1092The router will join the following multicast group when rtadvd(8) is available 1093for the interface. 1094o All-Routers Multicast Addresses (ff02::2) 1095 1096Routing daemons will join appropriate multicast groups, as necessary, 1097like ff02::9 for RIPng. 1098 1099Users can join groups by using appropriate system calls like setsockopt(2). 1100 |
|
| 7082. Network Drivers 709 | 11012. Network Drivers 1102 |
| 710KAME requires two items to be added into the standard drivers: | 1103KAME requires three items to be added into the standard drivers: |
| 711 712(1) mbuf clustering requirement. In this stable release, we changed 713 MINCLSIZE into MHLEN+1 for all the operating systems in order to make | 1104 1105(1) mbuf clustering requirement. In this stable release, we changed 1106 MINCLSIZE into MHLEN+1 for all the operating systems in order to make |
| 714 all the drivers behave as we expect. | 1107 all the drivers behave as we expect. |
| 715 716(2) multicast. If "ifmcstat" yields no multicast group for a 717 interface, that interface has to be patched. 718 | 1108 1109(2) multicast. If "ifmcstat" yields no multicast group for a 1110 interface, that interface has to be patched. 1111 |
| 719If any of the driver don't support the requirements, then the driver 720can't be used for IPv6 and/or IPsec communication. If you find any 721problem with your card using IPv6/IPsec, then, please report it to 722freebsd-bugs@freebsd.org. | 1112To avoid troubles, we suggest you to comment out the device drivers 1113for unsupported/unnecessary cards, from the kernel configuration file. 1114If you accidentally enable unsupported drivers, some of the userland 1115tools may not work correctly (routing daemons are typical example). |
| 723 | 1116 |
| 1117In the following sections, "official support" means that KAME developers 1118are using that ethernet card/driver frequently. 1119 |
|
| 724(NOTE: In the past we required all pcmcia drivers to have a call to 725in6_ifattach(). We have no such requirement any more) 726 | 1120(NOTE: In the past we required all pcmcia drivers to have a call to 1121in6_ifattach(). We have no such requirement any more) 1122 |
| 11232.1 FreeBSD 2.2.x-RELEASE 1124 1125Here is a list of FreeBSD 2.2.x-RELEASE drivers and its conditions: 1126 1127 driver mbuf(1) multicast(2) official support? 1128 --- --- --- --- 1129 (Ethernet) 1130 ar looks ok - - 1131 cnw ok ok yes (*) 1132 ed ok ok yes 1133 ep ok ok yes 1134 fe ok ok yes 1135 sn looks ok - - (*) 1136 vx looks ok - - 1137 wlp ok ok - (*) 1138 xl ok ok yes 1139 zp ok ok - 1140 (FDDI) 1141 fpa looks ok ? - 1142 (ATM) 1143 en ok ok yes 1144 (Serial) 1145 lp ? - not work 1146 sl ? - not work 1147 sr looks ok ok - (**) 1148 1149You may want to add an invocation of "rtsol" in "/etc/pccard_ether", 1150if you are using notebook computers and PCMCIA ethernet card. 1151 1152(*) These drivers are distributed with PAO (http://www.jp.freebsd.org/PAO/). 1153 1154(**) There was some report says that, if you make sr driver up and down and 1155then up, the kernel may hang up. We have disabled frame-relay support from 1156sr driver and after that this looks to be working fine. If you need 1157frame-relay support to come back, please contact KAME developers. 1158 11592.2 BSD/OS 3.x 1160 1161The following lists BSD/OS 3.x device drivers and its conditions: 1162 1163 driver mbuf(1) multicast(2) official support? 1164 --- --- --- --- 1165 (Ethernet) 1166 cnw ok ok yes 1167 de ok ok - 1168 df ok ok - 1169 eb ok ok - 1170 ef ok ok yes 1171 exp ok ok - 1172 mz ok ok yes 1173 ne ok ok yes 1174 we ok ok - 1175 (FDDI) 1176 fpa ok ok - 1177 (ATM) 1178 en maybe ok - 1179 (Serial) 1180 ntwo ok ok yes 1181 sl ? - not work 1182 appp ? - not work 1183 1184You may want to use "@insert" directive in /etc/pccard.conf to invoke 1185"rtsol" command right after dynamic insertion of PCMCIA ethernet cards. 1186 11872.3 NetBSD 1188 1189The following table lists the network drivers we have tried so far. 1190 1191 driver mbuf(1) multicast(2) official support? 1192 --- --- --- --- 1193 (Ethernet) 1194 awi pcmcia/i386 ok ok - 1195 bah zbus/amiga NG(*) 1196 cnw pcmcia/i386 ok ok yes 1197 ep pcmcia/i386 ok ok - 1198 le sbus/sparc ok ok yes 1199 ne pci/i386 ok ok yes 1200 ne pcmcia/i386 ok ok yes 1201 wi pcmcia/i386 ok ok yes 1202 (ATM) 1203 en pci/i386 ok ok - 1204 1205(*) This may need some fix, but I'm not sure what arcnet interfaces assume... 1206 12072.4 FreeBSD 3.x-RELEASE 1208 1209Here is a list of FreeBSD 3.x-RELEASE drivers and its conditions: 1210 1211 driver mbuf(1) multicast(2) official support? 1212 --- --- --- --- 1213 (Ethernet) 1214 cnw ok ok -(*) 1215 ed ? ok - 1216 ep ok ok - 1217 fe ok ok yes 1218 fxp ?(**) 1219 lnc ? ok - 1220 sn ? ? -(*) 1221 wi ok ok yes 1222 xl ? ok - 1223 1224(*) These drivers are distributed with PAO as PAO3 1225 (http://www.jp.freebsd.org/PAO/). 1226(**) there are trouble reports with multicast filter initialization. 1227 1228More drivers will just simply work on KAME FreeBSD 3.x-RELEASE but have not 1229been checked yet. 1230 12312.5 OpenBSD 2.x 1232 1233Here is a list of OpenBSD 2.x drivers and its conditions: 1234 1235 driver mbuf(1) multicast(2) official support? 1236 --- --- --- --- 1237 (Ethernet) 1238 de pci/i386 ok ok yes 1239 fxp pci/i386 ?(*) 1240 le sbus/sparc ok ok yes 1241 ne pci/i386 ok ok yes 1242 ne pcmcia/i386 ok ok yes 1243 wi pcmcia/i386 ok ok yes 1244 1245(*) There seem to be some problem in driver, with multicast filter 1246configuration. This happens with certain revision of chipset on the card. 1247Should be fixed by now by workaround in sys/net/if.c, but still not sure. 1248 12492.6 BSD/OS 4.x 1250 1251The following lists BSD/OS 4.x device drivers and its conditions: 1252 1253 driver mbuf(1) multicast(2) official support? 1254 --- --- --- --- 1255 (Ethernet) 1256 de ok ok yes 1257 exp (*) 1258 1259You may want to use "@insert" directive in /etc/pccard.conf to invoke 1260"rtsol" command right after dynamic insertion of PCMCIA ethernet cards. 1261 1262(*) exp driver has serious conflict with KAME initialization sequence. 1263A workaround is committed into sys/i386/pci/if_exp.c, and should be okay by now. 1264 |
|
| 7273. Translator 728 729We categorize IPv4/IPv6 translator into 4 types. 730 731Translator A --- It is used in the early stage of transition to make 732it possible to establish a connection from an IPv6 host in an IPv6 733island to an IPv4 host in the IPv4 ocean. 734 --- 6 unchanged lines hidden (view full) --- 741to an IPv6 host in the IPv6 ocean. 742 743Translator D --- It is used in the late stage of transition to make it 744possible to establish a connection from an IPv6 host in the IPv6 ocean 745to an IPv4 host in an IPv4 island. 746 747KAME provides an TCP relay translator for category A. This is called 748"FAITH". We also provide IP header translator for category A. | 12653. Translator 1266 1267We categorize IPv4/IPv6 translator into 4 types. 1268 1269Translator A --- It is used in the early stage of transition to make 1270it possible to establish a connection from an IPv6 host in an IPv6 1271island to an IPv4 host in the IPv4 ocean. 1272 --- 6 unchanged lines hidden (view full) --- 1279to an IPv6 host in the IPv6 ocean. 1280 1281Translator D --- It is used in the late stage of transition to make it 1282possible to establish a connection from an IPv6 host in the IPv6 ocean 1283to an IPv4 host in an IPv4 island. 1284 1285KAME provides an TCP relay translator for category A. This is called 1286"FAITH". We also provide IP header translator for category A. |
| 749(The latter is not yet put into FreeBSD4.x yet.) | |
| 750 7513.1 FAITH TCP relay translator 752 753FAITH system uses TCP relay daemon called "faithd" helped by the KAME kernel. 754FAITH will reserve an IPv6 address prefix, and relay TCP connection 755toward that prefix to IPv4 destination. 756 757For example, if the reserved IPv6 prefix is 3ffe:0501:0200:ffff::, and --- 5 unchanged lines hidden (view full) --- 763 | IPv4 tcp toward 163.221.202.12 764 FAITH-relay dual stack node 765 ^ 766 | IPv6 TCP toward 3ffe:0501:0200:ffff::163.221.202.12 767 source IPv6 node 768 769faithd must be invoked on FAITH-relay dual stack node. 770 | 1287 12883.1 FAITH TCP relay translator 1289 1290FAITH system uses TCP relay daemon called "faithd" helped by the KAME kernel. 1291FAITH will reserve an IPv6 address prefix, and relay TCP connection 1292toward that prefix to IPv4 destination. 1293 1294For example, if the reserved IPv6 prefix is 3ffe:0501:0200:ffff::, and --- 5 unchanged lines hidden (view full) --- 1300 | IPv4 tcp toward 163.221.202.12 1301 FAITH-relay dual stack node 1302 ^ 1303 | IPv6 TCP toward 3ffe:0501:0200:ffff::163.221.202.12 1304 source IPv6 node 1305 1306faithd must be invoked on FAITH-relay dual stack node. 1307 |
| 771For more details, consult src/usr.sbin/faithd/README. | 1308For more details, consult kame/kame/faithd/README and 1309draft-ietf-ngtrans-tcpudp-relay-01.txt. |
| 772 7733.2 IPv6-to-IPv4 header translator 774 | 1310 13113.2 IPv6-to-IPv4 header translator 1312 |
| 775(to be written) | 1313# removed since it is not imported to FreeBSD-current |
| 776 7774. IPsec 778 | 1314 13154. IPsec 1316 |
| 779IPsec is mainly organized by three components. | 1317IPsec is implemented as the following three components. |
| 780 781(1) Policy Management 782(2) Key Management | 1318 1319(1) Policy Management 1320(2) Key Management |
| 783(3) AH and ESP handling | 1321(3) AH, ESP and IPComp handling in kernel |
| 784 | 1322 |
| 1323Note that KAME/OpenBSD does NOT include support for KAME IPsec code, 1324as OpenBSD team has their home-brew IPsec stack and they have no plan 1325to replace it. IPv6 support for IPsec is, therefore, lacking on KAME/OpenBSD. 1326 |
|
| 7854.1 Policy Management 786 787The kernel implements experimental policy management code. There are two way 788to manage security policy. One is to configure per-socket policy using 789setsockopt(3). In this cases, policy configuration is described in 790ipsec_set_policy(3). The other is to configure kernel packet filter-based 791policy using PF_KEY interface, via setkey(8). 792 | 13274.1 Policy Management 1328 1329The kernel implements experimental policy management code. There are two way 1330to manage security policy. One is to configure per-socket policy using 1331setsockopt(3). In this cases, policy configuration is described in 1332ipsec_set_policy(3). The other is to configure kernel packet filter-based 1333policy using PF_KEY interface, via setkey(8). 1334 |
| 793The policy entry is not re-ordered with its 794indexes, so the order of entry when you add is very significant. | 1335The policy entry will be matched in order. The order of entries makes 1336difference in behavior. |
| 795 7964.2 Key Management 797 798The key management code implemented in this kit (sys/netkey) is a 799home-brew PFKEY v2 implementation. This conforms to RFC2367. 800 | 1337 13384.2 Key Management 1339 1340The key management code implemented in this kit (sys/netkey) is a 1341home-brew PFKEY v2 implementation. This conforms to RFC2367. 1342 |
| 801The home-brew IKE daemon, "racoon" is included in the kit 802(kame/kame/racoon). | 1343The home-brew IKE daemon, "racoon" is included in the kit (kame/kame/racoon, 1344or usr.sbin/racoon). |
| 803Basically you'll need to run racoon as daemon, then setup a policy 804to require keys (like ping -P 'out ipsec esp/transport//use'). 805The kernel will contact racoon daemon as necessary to exchange keys. 806 | 1345Basically you'll need to run racoon as daemon, then setup a policy 1346to require keys (like ping -P 'out ipsec esp/transport//use'). 1347The kernel will contact racoon daemon as necessary to exchange keys. 1348 |
| 1349In IKE spec, there's ambiguity about interpretation of "tunnel" proposal. 1350For example, if we would like to propose the use of following packet: 1351 IP AH ESP IP payload 1352some implementation proposes it as "AH transport and ESP tunnel", since 1353this is more logical from packet construction point of view. Some 1354implementation proposes it as "AH tunnel and ESP tunnel". 1355Racoon follows the former route. 1356This raises real interoperability issue. We hope this to be resolved quickly. 1357 |
|
| 8074.3 AH and ESP handling 808 809IPsec module is implemented as "hooks" to the standard IPv4/IPv6 810processing. When sending a packet, ip{,6}_output() checks if ESP/AH 811processing is required by checking if a matching SPD (Security 812Policy Database) is found. If ESP/AH is needed, 813{esp,ah}{4,6}_output() will be called and mbuf will be updated 814accordingly. When a packet is received, {esp,ah}4_input() will be --- 7 unchanged lines hidden (view full) --- 822extra daisy-chained headers inserted by ESP/AH. Our code takes care of 823the case. 824 825Basic crypto functions can be found in directory "sys/crypto". ESP/AH 826transform are listed in {esp,ah}_core.c with wrapper functions. If you 827wish to add some algorithm, add wrapper function in {esp,ah}_core.c, and 828add your crypto algorithm code into sys/crypto. 829 | 13584.3 AH and ESP handling 1359 1360IPsec module is implemented as "hooks" to the standard IPv4/IPv6 1361processing. When sending a packet, ip{,6}_output() checks if ESP/AH 1362processing is required by checking if a matching SPD (Security 1363Policy Database) is found. If ESP/AH is needed, 1364{esp,ah}{4,6}_output() will be called and mbuf will be updated 1365accordingly. When a packet is received, {esp,ah}4_input() will be --- 7 unchanged lines hidden (view full) --- 1373extra daisy-chained headers inserted by ESP/AH. Our code takes care of 1374the case. 1375 1376Basic crypto functions can be found in directory "sys/crypto". ESP/AH 1377transform are listed in {esp,ah}_core.c with wrapper functions. If you 1378wish to add some algorithm, add wrapper function in {esp,ah}_core.c, and 1379add your crypto algorithm code into sys/crypto. 1380 |
| 830Tunnel mode is partially supported in this release, with the following 831restrictions: 832- IPsec tunnel is not combined with GIF generic tunneling interface. 833 It needs a great care because we may create an infinite loop between 834 ip_output() and tunnelifp->if_output(). Opinion varies if it is better 835 to unify them, or not. 836- MTU and Don't Fragment bit (IPv4) considerations need more checking, but 837 basically works fine. | 1381Tunnel mode works basically fine, but comes with the following restrictions: 1382- You cannot run routing daemon across IPsec tunnel, since we do not model 1383 IPsec tunnel as pseudo interfaces. |
| 838- Authentication model for AH tunnel must be revisited. We'll need to 839 improve the policy management engine, eventually. | 1384- Authentication model for AH tunnel must be revisited. We'll need to 1385 improve the policy management engine, eventually. |
| 1386- Tunnelling for IPv6 IPsec is still incomplete. This is disabled by default. 1387 If you need to perform experiments, add "options IPSEC_IPV6FWD" into 1388 the kernel configuration file. Note that path MTU discovery does not work 1389 across IPv6 IPsec tunnel gateway due to insufficient code. |
|
| 840 | 1390 |
| 8414.4 Conformance to RFCs and IDs | 1391AH specificaton does not talk much about "multiple AH on a packet" case. 1392We incrementally compute AH checksum, from inside to outside. Also, we 1393treat inner AH to be immutable. 1394For example, if we are to create the following packet: 1395 IP AH1 AH2 AH3 payload 1396we do it incrementally. As a result, we get crypto checksums like below: 1397 AH3 has checksum against "IP AH3' payload". 1398 where AH3' = AH3 with checksum field filled with 0. 1399 AH2 has checksum against "IP AH2' AH3 payload". 1400 AH1 has checksum against "IP AH1' AH2 AH3 payload", 1401Also note that AH3 has the smallest sequence number, and AH1 has the largest 1402sequence number. |
| 842 | 1403 |
| 14044.4 IPComp handling 1405 1406IPComp stands for IP payload compression protocol. This is aimed for 1407payload compression, not the header compression like PPP VJ compression. 1408This may be useful when you are using slow serial link (say, cell phone) 1409with powerful CPU (well, recent notebook PCs are really powerful...). 1410The protocol design of IPComp is very similar to IPsec, though it was 1411defined separately from IPsec itself. 1412 1413Here are some points to be noted: 1414- IPComp is treated as part of IPsec protocol suite, and SPI and 1415 CPI space is unified. Spec says that there's no relationship 1416 between two so they are assumed to be separate in specs. 1417- IPComp association (IPCA) is kept in SAD. 1418- It is possible to use well-known CPI (CPI=2 for DEFLATE for example), 1419 for outbound/inbound packet, but for indexing purposes one element from 1420 SPI/CPI space will be occupied anyway. 1421- pfkey is modified to support IPComp. However, there's no official 1422 SA type number assignment yet. Portability with other IPComp 1423 stack is questionable (anyway, who else implement IPComp on UN*X?). 1424- Spec says that IPComp output processing must be performed before AH/ESP 1425 output processing, to achieve better compression ratio and "stir" data 1426 stream before encryption. The most meaningful processing order is: 1427 (1) compress payload by IPComp, (2) encrypt payload by ESP, then (3) attach 1428 authentication data by AH. 1429 However, with manual SPD setting, you are able to violate the ordering 1430 (KAME code is too generic, maybe). Also, it is just okay to use IPComp 1431 alone, without AH/ESP. 1432- Though the packet size can be significantly decreased by using IPComp, no 1433 special consideration is made about path MTU (spec talks nothing about MTU 1434 consideration). IPComp is designed for serial links, not ethernet-like 1435 medium, it seems. 1436- You can change compression ratio on outbound packet, by changing 1437 deflate_policy in sys/netinet6/ipcomp_core.c. You can also change outbound 1438 history buffer size by changing deflate_window_out in the same source code. 1439 (should it be sysctl accessible, or per-SAD configurable?) 1440- Tunnel mode IPComp is not working right. KAME box can generate tunnelled 1441 IPComp packet, however, cannot accept tunneled IPComp packet. 1442- You can negotiate IPComp association with racoon IKE daemon. 1443- KAME code does not attach Adler32 checksum to compressed data. 1444 see ipsec wg mailing list discussion in Jan 2000 for details. 1445 14464.5 Conformance to RFCs and IDs 1447 |
|
| 843The IPsec code in the kernel conforms (or, tries to conform) to the 844following standards: 845 "old IPsec" specification documented in rfc182[5-9].txt 846 "new IPsec" specification documented in rfc240[1-6].txt, rfc241[01].txt, 847 rfc2451.txt and draft-mcdonald-simple-ipsec-api-01.txt (draft expired, 848 but you can take from ftp://ftp.kame.net/pub/internet-drafts/). | 1448The IPsec code in the kernel conforms (or, tries to conform) to the 1449following standards: 1450 "old IPsec" specification documented in rfc182[5-9].txt 1451 "new IPsec" specification documented in rfc240[1-6].txt, rfc241[01].txt, 1452 rfc2451.txt and draft-mcdonald-simple-ipsec-api-01.txt (draft expired, 1453 but you can take from ftp://ftp.kame.net/pub/internet-drafts/). |
| 849 (NOTE: IKE specifications, rfc241[7-9].txt are implemented in userland, | 1454 (NOTE: IKE specifications, rfc240[7-9].txt are implemented in userland, |
| 850 as "racoon" IKE daemon) | 1455 as "racoon" IKE daemon) |
| 1456 IPComp: 1457 RFC2393: IP Payload Compression Protocol (IPComp) |
|
| 851 852Currently supported algorithms are: 853 old IPsec AH 854 null crypto checksum (no document, just for debugging) 855 keyed MD5 with 128bit crypto checksum (rfc1828.txt) 856 keyed SHA1 with 128bit crypto checksum (no document) 857 HMAC MD5 with 128bit crypto checksum (rfc2085.txt) 858 HMAC SHA1 with 128bit crypto checksum (no document) --- 13 unchanged lines hidden (view full) --- 872 DES-CBC with explicit IV (rfc2405.txt) 873 3DES-CBC with explicit IV (rfc2451.txt) 874 BLOWFISH CBC (rfc2451.txt) 875 CAST128 CBC (rfc2451.txt) 876 RC5 CBC (rfc2451.txt) 877 each of the above can be combined with: 878 ESP authentication with HMAC-MD5(96bit) 879 ESP authentication with HMAC-SHA1(96bit) | 1458 1459Currently supported algorithms are: 1460 old IPsec AH 1461 null crypto checksum (no document, just for debugging) 1462 keyed MD5 with 128bit crypto checksum (rfc1828.txt) 1463 keyed SHA1 with 128bit crypto checksum (no document) 1464 HMAC MD5 with 128bit crypto checksum (rfc2085.txt) 1465 HMAC SHA1 with 128bit crypto checksum (no document) --- 13 unchanged lines hidden (view full) --- 1479 DES-CBC with explicit IV (rfc2405.txt) 1480 3DES-CBC with explicit IV (rfc2451.txt) 1481 BLOWFISH CBC (rfc2451.txt) 1482 CAST128 CBC (rfc2451.txt) 1483 RC5 CBC (rfc2451.txt) 1484 each of the above can be combined with: 1485 ESP authentication with HMAC-MD5(96bit) 1486 ESP authentication with HMAC-SHA1(96bit) |
| 1487 IPComp 1488 RFC2394: IP Payload Compression Using DEFLATE |
|
| 880 881The following algorithms are NOT supported: 882 old IPsec AH 883 HMAC MD5 with 128bit crypto checksum + 64bit replay prevention 884 (rfc2085.txt) 885 keyed SHA1 with 160bit crypto checksum + 32bit padding (rfc1852.txt) 886 | 1489 1490The following algorithms are NOT supported: 1491 old IPsec AH 1492 HMAC MD5 with 128bit crypto checksum + 64bit replay prevention 1493 (rfc2085.txt) 1494 keyed SHA1 with 160bit crypto checksum + 32bit padding (rfc1852.txt) 1495 |
| 887IPsec (in kernel) and IKE (in userland as "racoon") has been tested 888at several interoperability test events, and it is known to interoperate 889with many other implementations well. Also, KAME IPsec has quite wide 890coverage for IPsec crypto algorithms documented in RFC (we cover 891algorithms without intellectual property issues only). | 1496The key/policy management API is based on the following document, with fair 1497amount of extensions: 1498 RFC2367: PF_KEY key management API |
| 892 | 1499 |
| 8934.5 ECN consideration on IPsec tunnels | 15004.6 ECN consideration on IPsec tunnels |
| 894 895KAME IPsec implements ECN-friendly IPsec tunnel, described in | 1501 1502KAME IPsec implements ECN-friendly IPsec tunnel, described in |
| 896draft-ipsec-ecn-00.txt. | 1503draft-ietf-ipsec-ecn-02.txt. |
| 897Normal IPsec tunnel is described in RFC2401. On encapsulation, 898IPv4 TOS field (or, IPv6 traffic class field) will be copied from inner 899IP header to outer IP header. On decapsulation outer IP header 900will be simply dropped. The decapsulation rule is not compatible 901with ECN, since ECN bit on the outer IP TOS/traffic class field will be 902lost. 903To make IPsec tunnel ECN-friendly, we should modify encapsulation 904and decapsulation procedure. This is described in | 1504Normal IPsec tunnel is described in RFC2401. On encapsulation, 1505IPv4 TOS field (or, IPv6 traffic class field) will be copied from inner 1506IP header to outer IP header. On decapsulation outer IP header 1507will be simply dropped. The decapsulation rule is not compatible 1508with ECN, since ECN bit on the outer IP TOS/traffic class field will be 1509lost. 1510To make IPsec tunnel ECN-friendly, we should modify encapsulation 1511and decapsulation procedure. This is described in |
| 905http://www.aciri.org/floyd/papers/draft-ipsec-ecn-00.txt, chapter 3. | 1512draft-ietf-ipsec-ecn-02.txt, chapter 3.3. |
| 906 907KAME IPsec tunnel implementation can give you three behaviors, by setting 908net.inet.ipsec.ecn (or net.inet6.ipsec6.ecn) to some value: 909- RFC2401: no consideration for ECN (sysctl value -1) 910- ECN forbidden (sysctl value 0) 911- ECN allowed (sysctl value 1) 912Note that the behavior is configurable in per-node manner, not per-SA manner | 1513 1514KAME IPsec tunnel implementation can give you three behaviors, by setting 1515net.inet.ipsec.ecn (or net.inet6.ipsec6.ecn) to some value: 1516- RFC2401: no consideration for ECN (sysctl value -1) 1517- ECN forbidden (sysctl value 0) 1518- ECN allowed (sysctl value 1) 1519Note that the behavior is configurable in per-node manner, not per-SA manner |
| 913(draft-ipsec-ecn-00 wants per-SA configuration, but it looks too much for me). | 1520(draft-ietf-ipsec-ecn-02 wants per-SA configuration, but it looks too much 1521for me). |
| 914 915The behavior is summarized as follows (see source code for more detail): 916 917 encapsulate decapsulate 918 --- --- 919RFC2401 copy all TOS bits drop TOS bits on outer 920 from inner to outer. (use inner TOS bits as is) 921 --- 10 unchanged lines hidden (view full) --- 932- if both IPsec tunnel endpoint are capable of ECN-friendly behavior, 933 you'd better configure both end to "ECN allowed" (sysctl value 1). 934- if the other end is very strict about TOS bit, use "RFC2401" 935 (sysctl value -1). 936- in other cases, use "ECN forbidden" (sysctl value 0). 937The default behavior is "ECN forbidden" (sysctl value 0). 938 939For more information, please refer to: | 1522 1523The behavior is summarized as follows (see source code for more detail): 1524 1525 encapsulate decapsulate 1526 --- --- 1527RFC2401 copy all TOS bits drop TOS bits on outer 1528 from inner to outer. (use inner TOS bits as is) 1529 --- 10 unchanged lines hidden (view full) --- 1540- if both IPsec tunnel endpoint are capable of ECN-friendly behavior, 1541 you'd better configure both end to "ECN allowed" (sysctl value 1). 1542- if the other end is very strict about TOS bit, use "RFC2401" 1543 (sysctl value -1). 1544- in other cases, use "ECN forbidden" (sysctl value 0). 1545The default behavior is "ECN forbidden" (sysctl value 0). 1546 1547For more information, please refer to: |
| 940 http://www.aciri.org/floyd/papers/draft-ipsec-ecn-00.txt | 1548 draft-ietf-ipsec-ecn-02.txt |
| 941 RFC2481 (Explicit Congestion Notification) 942 KAME sys/netinet6/{ah,esp}_input.c 943 944(Thanks goes to Kenjiro Cho <kjc@csl.sony.co.jp> for detailed analysis) 945 | 1549 RFC2481 (Explicit Congestion Notification) 1550 KAME sys/netinet6/{ah,esp}_input.c 1551 1552(Thanks goes to Kenjiro Cho <kjc@csl.sony.co.jp> for detailed analysis) 1553 |
| 9464.6 Interoperability | 15544.7 Interoperability |
| 947 | 1555 |
| 1556IPsec, IPComp (in kernel) and IKE (in userland as "racoon") has been tested 1557at several interoperability test events, and it is known to interoperate 1558with many other implementations well. Also, KAME IPsec has quite wide 1559coverage for IPsec crypto algorithms documented in RFC (we do not cover 1560algorithms with intellectual property issues, though). 1561 |
|
| 948Here are (some of) platforms we have tested IPsec/IKE interoperability | 1562Here are (some of) platforms we have tested IPsec/IKE interoperability |
| 949in the past. Note that both ends (KAME and others) may have modified their 950implementation, so use the following list just for reference purposes. 951 Altiga, Ashley-laurent (vpcom.com), Data Fellows (F-Secure), Ericsson 952 ACC, FreeS/WAN, HITACHI, IBM AIX, IIJ, Intel, Microsoft WinNT, NIST 953 (linux IPsec + plutoplus), Netscreen, OpenBSD, RedCreek, Routerware, 954 SSH, Secure Computing, Soliton, Toshiba, VPNet, Yamaha RT100i | 1563in the past, in no particular order. Note that both ends (KAME and 1564others) may have modified their implementation, so use the following 1565list just for reference purposes. 1566 Altiga, Ashley-laurent (vpcom.com), Data Fellows (F-Secure), 1567 BlueSteel, CISCO, Ericsson, ACC, Fitel, FreeS/WAN, HITACHI, IBM 1568 AIX, IIJ, Intel, Microsoft WinNT, NAI PGPnet, 1569 NIST (linux IPsec + plutoplus), Netscreen, OpenBSD isakmpd, Radguard, 1570 RedCreek, Routerware, SSH, Secure Computing, Soliton, Toshiba, 1571 TIS/NAI Gauntret, VPNet, Yamaha RT100i |
| 955 | 1572 |
| 9565. IPComp 957(not yet put into FreeBSD4.x, due to inflate related changes in 4.x.) | 1573Here are (some of) platforms we have tested IPComp/IKE interoperability 1574in the past, in no particular order. 1575 IRE |
| 958 | 1576 |
| 959IPComp stands for IP payload compression protocol. This is aimed for 960payload compression, not the header compression like PPP VJ compression. 961This may be useful when you are using slow serial link (say, cell phone) 962with powerful CPU (well, recent notebook PCs are really powerful...). 963The protocol design of IPComp is very similar to IPsec. | 15775. ALTQ |
| 964 | 1578 |
| 965KAME implements the following specifications: 966- RFC2393: IP Payload Compression Protocol (IPComp) 967- RFC2394: IP Payload Compression Using DEFLATE | 1579# removed since it is not imported to FreeBSD-current |
| 968 | 1580 |
| 969Here are some points to be noted: 970- IPComp is treated as part of IPsec protocol suite, and SPI and 971 CPI space is unified. Spec says that there's no relationship 972 between two so they are assumed to be separate. 973- IPComp association (IPCA) is kept in SAD. 974- It is possible to use well-known CPI (CPI=2 for DEFLATE for example), 975 for outbound/inbound packet, but for indexing purposes one element from 976 SPI/CPI space will be occupied anyway. 977- pfkey is modified to support IPComp. However, there's no official 978 SA type number assignment yet. Portability with other IPComp 979 stack is questionable (anyway, who else implement IPComp on UN*X?). 980- Spec says that IPComp output processing must be performed before IPsec 981 output processing, to achieve better compression ratio and "stir" data 982 stream before encryption. However, with manual SPD setting, you are able to 983 violate the ordering requirement (KAME code is too generic, maybe). 984- Though MTU can be significantly decreased by using IPComp, no special 985 consideration is made about path MTU (spec talks nothing about MTU 986 consideration). IPComp is designed for serial links, not ethernet-like 987 medium, it seems. 988- You can change compression ratio on outbound packet, by changing 989 deflate_policy in sys/netinet6/ipcomp_core.c. You can also change history 990 buffer size by changing deflate_window in the same source code. 991 (should it be sysctl accessible? or per-SAD configurable?) 992- Tunnel mode IPComp is not working right. KAME box can generate tunnelled 993 IPComp packet, however, cannot accept tunneled IPComp packet. | 15816. mobile-ip6 |
| 994 | 1582 |
| 9956. ALTQ 996 (not yet put into FreeBSD4.x) | 1583# removed since it is not imported to FreeBSD-current |
| 997 998 <end of IMPLEMENTATION> | 1584 1585 <end of IMPLEMENTATION> |