Babel Routing Protocol over Datagram Transport Layer Security
RFC 8968
Internet Engineering Task Force (IETF) A. Décimo
Request for Comments: 8968 IRIF, University of Paris-Diderot
Category: Standards Track D. Schinazi
ISSN: 2070-1721 Google LLC
J. Chroboczek
IRIF, University of Paris-Diderot
January 2021
Babel Routing Protocol over Datagram Transport Layer Security
Abstract
The Babel Routing Protocol does not contain any means to authenticate
neighbours or provide integrity or confidentiality for messages sent
between them. This document specifies a mechanism to ensure these
properties using Datagram Transport Layer Security (DTLS).
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8968.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction
1.1. Specification of Requirements
1.2. Applicability
2. Operation of the Protocol
2.1. DTLS Connection Initiation
2.2. Protocol Encoding
2.3. Transmission
2.4. Reception
2.5. Neighbour Table Entry
2.6. Simultaneous Operation of Babel over DTLS and Unprotected
Babel on a Node
2.7. Simultaneous Operation of Babel over DTLS and Unprotected
Babel on a Network
3. Interface Maximum Transmission Unit Issues
4. IANA Considerations
5. Security Considerations
6. References
6.1. Normative References
6.2. Informative References
Appendix A. Performance Considerations
Acknowledgments
Authors' Addresses
1. Introduction
The Babel routing protocol [RFC8966] does not contain any means to
authenticate neighbours or protect messages sent between them.
Because of this, an attacker is able to send maliciously crafted
Babel messages that could lead a network to route traffic to an
attacker or to an under-resourced target, causing denial of service.
This document specifies a mechanism to prevent such attacks using
Datagram Transport Layer Security (DTLS) [RFC6347].
1.1. Specification of Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
1.2. Applicability
The protocol described in this document protects Babel packets with
DTLS. As such, it inherits the features offered by DTLS, notably
authentication, integrity, optional replay protection,
confidentiality, and asymmetric keying. It is therefore expected to
be applicable in a wide range of environments.
There exists another mechanism for securing Babel, namely Message
Authentication Code (MAC) authentication for Babel (Babel-MAC)
[RFC8967]. Babel-MAC only offers basic features, namely
authentication, integrity, and replay protection with a small number
of symmetric keys. A comparison of Babel security mechanisms and
their applicability can be found in [RFC8966].
Note that Babel over DTLS provides a single authentication domain,
meaning that all nodes that have the right credentials can convey any
and all routing information.
DTLS supports several mechanisms by which nodes can identify
themselves and prove possession of secrets tied to these identities.
This document does not prescribe which of these mechanisms to use;
details of identity management are left to deployment profiles of
Babel over DTLS.
2. Operation of the Protocol
Babel over DTLS requires some changes to how Babel operates. First,
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