Internet DRAFT - draft-unyte-udp-notif-dtls
draft-unyte-udp-notif-dtls
NETCONF A. Huang Feng
Internet-Draft P. Francois
Intended status: Standards Track INSA-Lyon
Expires: January 13, 2022 T. Zhou
Huawei
M. Tollini
Swisscom
July 12, 2021
DTLS for UDP-notif
draft-unyte-udp-notif-dtls-00
Abstract
This document describes a DTLS layer for the UDP-notif protocol.
DTLS allows a server and a client to exchange secured messages over
UDP. This transport layer permits networking devices to send secured
UDP-notif messages over the network.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
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
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This Internet-Draft will expire on January 13, 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Transport . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Port Assignment . . . . . . . . . . . . . . . . . . . . . . . 4
4. Session lifecycle . . . . . . . . . . . . . . . . . . . . . . 4
4.1. DTLS Session Initiation . . . . . . . . . . . . . . . . . 4
4.2. Publish Data . . . . . . . . . . . . . . . . . . . . . . 4
4.3. Session termination . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
6.1. Normative References . . . . . . . . . . . . . . . . . . 6
6.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
UDP-notif [I-D.ietf-netconf-udp-notif] defines a lightweight
notification protocol allowing networking devices to send data over
UDP. This document describes a layer to secure UDP-notif messages
between the publisher and the receiver using the DTLS 1.3 protocol.
The DTLS 1.3 protocol [I-D.draft-ietf-tls-dtls13] is designed to meet
the requirements of applications that need to secure datagram
transport.
DTLS can be used as a secure transport to counter all the primary
threats to UDP-notif:
o Confidentiality to counter disclosure of the message contents.
o Integrity checking to counter modifications to a message on a hop-
by-hop basis.
o Server or mutual authentication to counter masquerade.
In addition, DTLS also provides:
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o A cookie exchange mechanism during handshake to counter Denial of
Service attacks.
o A sequence number in the header to counter replay attacks.
This document defines the requirements for the implementation of the
secured layer of DTLS for UDP-notif. No DTLS 1.3 extensions are
defined nor needed.
Section 2 describes the involved layers for this mechanism.
Section 3 describes the port management. Section 4 details the
session lifecycle of DTLS within UDP-notif.
2. Transport
As shown in Figure 1, the DTLS is layered next to the UDP transport
providing reusable security and authentication functions over UDP.
No DTLS extension is required to enable UDP-notif messages over DTLS.
+-----------------------------+
| UDP-notif Message |
+-----------------------------+
| DTLS |
+-----------------------------+
| UDP |
+-----------------------------+
| IP |
+-----------------------------+
Figure 1: Protocol Stack for DTLS secured UDP-notif
The application implementer will map a unique combination of the
remote address, remote port number, local address, and local port
number to a session.
Each UDP-notif message is delivered by the DTLS record protocol,
which assigns a sequence number to each DTLS record. Although the
DTLS implementer may adopt a queue mechanism to resolve reordering,
it may not assure that all the messages are delivered in order when
mapping on the UDP transport.
Since UDP is an unreliable transport, with DTLS, an originator or a
relay may not realize that a collector has gone down or lost its DTLS
connection state, so messages may be lost.
The DTLS record has its own sequence number, encryption and
decryption will be done by the DTLS layer, so that the UDP-notif
Message layer is not impacted by the use of DTLS.
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3. Port Assignment
The Publisher is always a DTLS client, and the Receiver is always a
DTLS server. The Receivers MUST support accepting UDP-notif Messages
on the specified UDP port, but MAY be configurable to listen on a
different port. The Publisher MUST support sending UDP-notif
messages to the specified UDP port, but MAY be configurable to send
messages to a different port. The Publisher MAY use any source UDP
port for transmitting messages.
4. Session lifecycle
4.1. DTLS Session Initiation
The Publisher initiates a DTLS connection by sending a DTLS
ClientHello to the Receiver. Implementations MAY support the denial
of service countermeasures defined by DTLS 1.3. When these
countermeasures are used, the Receiver responds with a DTLS
HelloRetryRequest containing a stateless cookie. The Publisher MUST
send a new DTLS ClientHello message containing the received cookie,
which initiates the DTLS handshake.
The Publisher MUST NOT send any UDP-notif messages before the DTLS
handshake has successfully completed.
Implementations MUST support DTLS 1.3 [I-D.draft-ietf-tls-dtls13] and
MUST support the mandatory to implement cipher suite
TLS_AES_128_GCM_SHA256 and SHOULD implement TLS_AES_256_GCM_SHA384
and TLS_CHACHA20_POLY1305_SHA256 cipher suites, as specified in TLS
1.3 [RFC8446]. If additional cipher suites are supported, then
implementations MUST NOT negotiate a cipher suite that employs NULL
integrity or authentication algorithms.
Where privacy is REQUIRED, then implementations must either negotiate
a cipher suite that employs a non-NULL encryption algorithm or
otherwise achieve privacy by other means, such as a physically
secured network.
4.2. Publish Data
All UDP-notif messages MUST be published as DTLS "application_data".
It is possible that multiple UDP-notif messages are contained in one
DTLS record, or that a publication message is transferred in multiple
DTLS records. The application data is defined with the following
ABNF [RFC5234] expression:
APPLICATION-DATA = 1*UDP-NOTIF-FRAME
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UDP-NOTIF-FRAME = MSG-LEN SP UDP-NOTIF-MSG
MSG-LEN = NONZERO-DIGIT *DIGIT
SP = %d32
NONZERO-DIGIT = %d49-57
DIGIT = %d48 / NONZERO-DIGIT
UDP-NOTIF-MSG is defined in [I-D.ietf-netconf-udp-notif].
The Publisher SHOULD attempt to avoid IP fragmentation by using the
Segmentation Option in the UDP-notif message.
4.3. Session termination
A Publisher MUST close the associated DTLS connection if the
connection is not expected to deliver any UDP-notif Messages later.
It MUST send a DTLS close_notify alert before closing the connection.
A Publisher (DTLS client) MAY choose to not wait for the Receiver's
close_notify alert and simply close the DTLS connection. Once the
Receiver gets a close_notify from the Publisher, it MUST reply with a
close_notify.
When no data is received from a DTLS connection for a long time, the
Receiver MAY close the connection. Implementations SHOULD set the
timeout value to 10 minutes but application specific profiles MAY
recommend shorter or longer values. The Receiver (DTLS server) MUST
attempt to initiate an exchange of close_notify alerts with the
Publisher before closing the connection. Receivers that are
unprepared to receive any more data MAY close the connection after
sending the close_notify alert.
Although closure alerts are a component of TLS and so of DTLS, they,
like all alerts, are not retransmitted by DTLS and so may be lost
over an unreliable network.
5. IANA Considerations
This RFC requests that IANA assigns one UDP port number in the
"Registered Port Numbers" range with the service name "udp-notif-
dtls". This port will be the default port for the UDP-based
notification Streaming Telemetry (UDP-Notif-DTLS) for NETCONF and
RESTCONF. Below is the registration template following the rules of
[RFC6335].
Service Name: udp-notif-dtls
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Transport Protocol(s): UDP
Assignee: IESG <iesg@ietf.org>
Contact: IETF Chair <chair@ietf.org>
Description: UDP-based Publication Streaming Telemetry
Reference: [RFC-to-be]
Port Number: TBD1
IANA is requested to assign a new URI from the IETF XML Registry
[RFC3688]. The following URI is suggested:
URI: urn:ietf:params:xml:ns:yang:ietf-udp-notif
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
This document also requests a new YANG module name in the YANG Module
Names registry [RFC7950] with the following suggestion:
name: ietf-udp-notif
namespace: urn:ietf:params:xml:ns:yang:ietf-udp-notif-dtls
prefix: un
reference: RFC XXXX
6. References
6.1. 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,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>.
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[RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S.
Cheshire, "Internet Assigned Numbers Authority (IANA)
Procedures for the Management of the Service Name and
Transport Protocol Port Number Registry", BCP 165,
RFC 6335, DOI 10.17487/RFC6335, August 2011,
<https://www.rfc-editor.org/info/rfc6335>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
6.2. Informative References
[I-D.draft-ietf-tls-dtls13]
Rescorla, E., Tschofenig, H., and N. Modadugu, "The
Datagram Transport Layer Security (DTLS) Protocol Version
1.3", draft-ietf-tls-dtls13-43 (work in progress), July
2021.
[I-D.ietf-netconf-udp-notif]
Zheng, G., Zhou, T., Graf, T., Francois, P., and P.
Lucente, "UDP-based Transport for Configured
Subscriptions", draft-ietf-netconf-udp-notif-03 (work in
progress), July 2021.
Authors' Addresses
Alex Huang Feng
INSA-Lyon
Lyon
France
Email: alex.huang-feng@insa-lyon.fr
Pierre Francois
INSA-Lyon
Lyon
France
Email: pierre.francois@insa-lyon.fr
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Tianran Zhou
Huawei
156 Beiqing Rd., Haidian District
Beijing
China
Email: zhoutianran@huawei.com
Marco Tollini
Swisscom
Binzring 17
Zuerich 8045
Switzerland
Email: marco.tollini1@swisscom.com
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