anima Working Group M. Richardson Internet-Draft Sandelman Software Works Intended status: Standards Track 25 January 2021 Expires: 29 July 2021 CBOR tags for IPv4 and IPv6 addresses and prefixes draft-richardson-cbor-network-addresses-00 Abstract This document describes two CBOR Tags to be used with IPv4 and IPv6 addresses and prefixes. RFC-EDITOR-please remove: This work is tracked at https://github.com/mcr/cbor-network-address.git 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 29 July 2021. Copyright Notice Copyright (c) 2021 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 carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Richardson Expires 29 July 2021 [Page 1] Internet-Draft CBOR-IP January 2021 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.1. IPv4 . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2.2. IPv6 . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Security Considerations . . . . . . . . . . . . . . . . . . . 3 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 4.1. TBD1 - IPv4 . . . . . . . . . . . . . . . . . . . . . . . 3 4.2. TBD2 - IPv6 . . . . . . . . . . . . . . . . . . . . . . . 3 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3 6. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 3 7. Normative References . . . . . . . . . . . . . . . . . . . . 3 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction [RFC8949] defines a number of CBOR Tags for common items. Not included are ones to indicate if the item is an IPv4 or IPv6 address, or if it is an address plus prefix length. This document defines them. 2. Protocol These tags can applied to byte strings to represent a single address. When applied to an array, the represent a CIDR-style prefix. When a byte string (without prefix) appears in a context where a prefix is expected, then it is to be assumed that all bits are relevant. That is, for IPv4, a /32 is implied, and for IPv6, a /128 is implied. 2.1. IPv4 IANA has allocated tag TBD1 for IPv4 uses. An IPv4 address is to be encoded as a four-byte bytestring ([RFC8949] section, 3.1, major type 2), prefixed with tag TBD1. Trailing zero octets may be omitted. An IPv4 prefix, such as 192.0.0.1/24 is to be encoded as a two element array: TBD1([ h'C0000001', 24]) Richardson Expires 29 July 2021 [Page 2] Internet-Draft CBOR-IP January 2021 2.2. IPv6 IANA has allocated tag TBD2 for IPv6 uses. An IPv6 address is to be encoded as up to sixteen-byte bytestring ([RFC8949] section, 3.1, major type 2), prefixed with tag TBD2. Trailing zero octets may be omitted. An IPv6 prefix, such as 2001:db8:1234::/48 is to be encoded as a two element array: TBD2([ h'20010db81234', 24]) 3. Security Considerations Identifying which byte sequences in a protocol are addresses may allow an attacker or eavesdropper to better understand what parts of a packet to attack. Reading the relevant RFC may provide more information, so it would seem that any additional security that was provided by not being able to identify what are IP addresses falls into the security by obscurity category. 4. IANA Considerations IANA is asked to allocate two tags from the Specification Required area, in the ("1+1") area. 4.1. TBD1 - IPv4 Data Item: byte-string and array Semantics: IPv4 or [IPv4,prefixlen] 4.2. TBD2 - IPv6 Data Item: byte-string and array Semantics: IPv6 or [IPv6,prefixlen] 5. Acknowledgements none yet 6. Changelog 7. Normative References Richardson Expires 29 July 2021 [Page 3] Internet-Draft CBOR-IP January 2021 [BCP14] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8949] Bormann, C. and P. Hoffman, "Concise Binary Object Representation (CBOR)", STD 94, RFC 8949, DOI 10.17487/RFC8949, December 2020, . Author's Address Michael Richardson Sandelman Software Works Email: mcr+ietf@sandelman.ca Richardson Expires 29 July 2021 [Page 4]