--- 1/draft-ietf-6man-ra-pref64-05.txt 2019-10-03 16:13:25.439931945 -0700 +++ 2/draft-ietf-6man-ra-pref64-06.txt 2019-10-03 16:13:25.475932852 -0700 @@ -1,40 +1,40 @@ IPv6 Maintenance L. Colitti Internet-Draft J. Linkova Intended status: Standards Track Google -Expires: April 2, 2020 September 30, 2019 +Expires: April 5, 2020 October 3, 2019 Discovering PREF64 in Router Advertisements - draft-ietf-6man-ra-pref64-05 + draft-ietf-6man-ra-pref64-06 Abstract This document specifies a Router Advertisement option to communicate - NAT64 prefixes to clients. + NAT64 prefixes to hosts. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on April 2, 2020. + This Internet-Draft will expire on April 5, 2020. Copyright Notice Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -45,24 +45,24 @@ described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2 2. Use cases for communicating the NAT64 prefix to hosts . . . . 3 3. Why include the NAT64 prefix in Router Advertisements . . . . 3 4. Usage Guidelines . . . . . . . . . . . . . . . . . . . . . . 4 - 5. Option format . . . . . . . . . . . . . . . . . . . . . . . . 5 + 5. Option format . . . . . . . . . . . . . . . . . . . . . . . . 4 6. Handling Multiple NAT64 Prefixes . . . . . . . . . . . . . . 6 7. PREF64 Consistency . . . . . . . . . . . . . . . . . . . . . 7 - 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 + 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 9. Security Considerations . . . . . . . . . . . . . . . . . . . 8 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 11.1. Normative References . . . . . . . . . . . . . . . . . . 8 11.2. Informative References . . . . . . . . . . . . . . . . . 9 11.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10 1. Introduction @@ -145,32 +145,24 @@ prefixes, but no NAT64 prefix). Updatability: it is possible to change the NAT64 prefix at any time, because when it changes, it is possible to notify hosts by sending a new Router Advertisement. Deployability: all IPv6 hosts and networks are required to support Neighbor Discovery [RFC4861] so just a minor extension to the existing implementation is required. Other options such as [RFC7225] require implementing other protocols (e.g. PCP [RFC7225]) which - could be considered an obstacle for deplyoment. + could be considered an obstacle for deployment. 4. Usage Guidelines - To support prefix lengths defined in [RFC6052] this option contains - the prefix length field. However as /96 prefix is considered to be - the most common use case, the prefix length field is optional and - only presents for non-/96 prefixes. It allows to keep the option - length to a minimum (16 octets) for the most common case and increase - it to 24 octets for non-/96 prefixes only (see Section 5 below for - more details). - This option specifies exactly one NAT64 prefix for all IPv4 destinations. If the network operator desires to route different parts of the IPv4 address space to different NAT64 devices, this can be accomplished by routing more specifics of the NAT64 prefix to those devices. For example, if the operator would like to route 10.0.0.0/8 through NAT64 device A and the rest of the IPv4 space through NAT64 device B, and the operator's NAT64 prefix is 2001:db8:a:b::/96, then the operator can route 2001:db8:a:b::a00:0/104 to NAT64 A and 2001:db8:a:b::/64 to NAT64 B. @@ -186,82 +178,82 @@ translated. An example might be private address ranges that are local to the network/provisioning domain and should not be reached through the NAT64. This type of configuration cannot be conveyed to hosts using this option, or through other NAT64 prefix provisioning mechanisms such as [RFC7050] or [RFC7225]. This problem does not apply in IPv6-only networks, because in such networks, the host does not have an IPv4 address and cannot reach any IPv4 destinations without the NAT64.. 5. Option format - 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ - | Type | Length | Lifetime | PL | + | Type | Length | Lifetime | PLC | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | Highest 96 bits of the Prefix | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: NAT64 Prefix Option Format Fields: Type 8-bit identifier of the PREF64 option type as assigned by IANA: TBD Length 8-bit unsigned integer. The length of the option (including the Type and Length fields) is in units of 8 octets. The sender MUST set the length to 2. The receiver MUST ignore the PREF64 option if the length field value is not 2. Lifetime 13-bit unsigned integer. The maximum time in units of 8 - secons over which this NAT64 prefix MAY be used. The value + seconds over which this NAT64 prefix MAY be used. The value of Lifetime SHOULD by default be set to the lesser of 3 x - MaxRtrAdvInterval divided by 8 or 8192. The reciever MUST - multiply the Lifetime value by 8 to calculate the maximum - time in seconds the prefix MAY be used. Lifetime of 0 - indicates that the prefix SHOULD NOT be used anymore. Router - vendors SHOULD allow adminstrators to specify non-zero - lifetime values which are not divisible by 8. In such cases - the router SHOULD round the provided value up to the lesser - of nearest integer divisible by 8 or 65536, divide the - result by 8 and set the Lifetime field to the resulting - value. + MaxRtrAdvInterval divided by 8, or 8191. The receiver MUST + multiply the Lifetime value by 8 (for example, by logical + left shift) to calculate the maximum time in seconds the + prefix MAY be used. Lifetime of 0 indicates that the prefix + SHOULD NOT be used anymore. Router vendors SHOULD allow + administrators to specify non-zero lifetime values which are + not divisible by 8. In such cases the router SHOULD round + the provided value up to the lesser of nearest integer + divisible by 8, or 65528 and divide the result by 8 (or just + perform a logical right-shift by 3) and set the Lifetime + field to the resulting value. - PL 3-bit unsigned integer.This field encodes the NAT64 Prefix - (Prefix Length. The PL field values 0,1,2,3,4 and 5 indicate the - Length) NAT64 prefix length of 96,64,56,48,40 and 32 bits - respectively. The reciever MUST ignore the PREF64 option if - the prefix length field is not set to one of those values. + PLC 3-bit unsigned integer. This field encodes the NAT64 Prefix + (Prefix Length defined in [RFC6052]. The PLC field values 0, 1, 2, + Length 3, 4 and 5 indicate the NAT64 prefix length of 96, 64, 56, + Code) 48, 40 and 32 bits respectively. The receiver MUST ignore + the PREF64 option if the prefix length code field is not set + to one of those values. Highest 96-bit unsigned integer. Contains bits 0 - 95 of the NAT64 96 bits prefix. of the prefix 6. Handling Multiple NAT64 Prefixes In some cases a host may receive multiple NAT64 prefixes from different sources. Possible scenarios include (but are not limited to): o the host is using multiple mechanisms to discover PREF64 prefixes (e.g. by using PCP [RFC7225]) and/or by resolving IPv4-only fully qualified domain name [RFC7050] in addition to receiving the PREF64 RA option); - o The pref64 option presents in a single RA more than once; - + o the PREF64 option presents in a single RA more than once; o the host receives multiple RAs with different PREF64 prefixes on one or multiple interfaces. When multiple PREF64 were discovered via RA PREF64 Option (the Option presents more than once in a single RA or multiple RAs were received), host behaviour with regards to synthesizing IPv6 addresses from IPv4 addresses SHOULD follow the recommendations given in Section 3 of [RFC7050], limited to the NAT64 prefixes that have non- zero lifetime.. @@ -329,21 +321,22 @@ Router Advertisements are only received from legitimate sources eliminate the problem of NAT64 prefix validation described in section 3.1 of [RFC7050]. 10. Acknowledgements Thanks to the following people (in alphabetical order) for their review and feedback: Mikael Abrahamsson, Mark Andrews, Brian E Carpenter, David Farmer, Nick Heatley, Robert Hinden, Martin Hunek, Tatuya Jinmei, Erik Kline, David Lamparter, Jordi Palet Martinez, - Tommy Pauly, Michael Richardson, David Schinazi, Ole Troan. + Tommy Pauly, Alexandre Petrescu, Michael Richardson, David Schinazi, + Ole Troan, Bernie Volz. 11. References 11.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . @@ -357,31 +350,20 @@ DOI 10.17487/RFC6052, October 2010, . [RFC7050] Savolainen, T., Korhonen, J., and D. Wing, "Discovery of the IPv6 Prefix Used for IPv6 Address Synthesis", RFC 7050, DOI 10.17487/RFC7050, November 2013, . 11.2. Informative References - [I-D.ietf-intarea-provisioning-domains] - Pfister, P., Vyncke, E., Pauly, T., Schinazi, D., and W. - Shao, "Discovering Provisioning Domain Names and Data", - draft-ietf-intarea-provisioning-domains-07 (work in - progress), September 2019. - - [RFC4033] Arends, R., Austein, R., Larson, M., Massey, D., and S. - Rose, "DNS Security Introduction and Requirements", - RFC 4033, DOI 10.17487/RFC4033, March 2005, - . - [RFC6105] Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., and J. Mohacsi, "IPv6 Router Advertisement Guard", RFC 6105, DOI 10.17487/RFC6105, February 2011, . [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146, April 2011, . @@ -394,44 +376,40 @@ [RFC6877] Mawatari, M., Kawashima, M., and C. Byrne, "464XLAT: Combination of Stateful and Stateless Translation", RFC 6877, DOI 10.17487/RFC6877, April 2013, . [RFC7225] Boucadair, M., "Discovering NAT64 IPv6 Prefixes Using the Port Control Protocol (PCP)", RFC 7225, DOI 10.17487/RFC7225, May 2014, . - [RFC7556] Anipko, D., Ed., "Multiple Provisioning Domain - Architecture", RFC 7556, DOI 10.17487/RFC7556, June 2015, - . - [RFC7858] Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D., and P. Hoffman, "Specification for DNS over Transport Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May 2016, . [RFC8305] Schinazi, D. and T. Pauly, "Happy Eyeballs Version 2: Better Connectivity Using Concurrency", RFC 8305, DOI 10.17487/RFC8305, December 2017, . 11.3. URIs [1] https://www.iana.org/assignments/icmpv6-parameters Authors' Addresses Lorenzo Colitti Google - Roppongi 6-10-1 - Minato, Tokyo 106-6126 + Shibuya 3-21-3 + Shibuya, Tokyo 150-0002 JP Email: lorenzo@google.com Jen Linkova Google 1 Darling Island Rd Pyrmont, NSW 2009 AU