draft-ietf-core-hop-limit-00.txt   draft-ietf-core-hop-limit-01.txt 
CORE M. Boucadair CORE M. Boucadair
Internet-Draft Orange Internet-Draft Orange
Intended status: Standards Track T. Reddy Intended status: Standards Track T. Reddy
Expires: March 21, 2019 McAfee Expires: May 10, 2019 McAfee
J. Shallow J. Shallow
NCC Group NCC Group
September 17, 2018 November 6, 2018
Constrained Application Protocol (CoAP) Hop Limit Option Constrained Application Protocol (CoAP) Hop Limit Option
draft-ietf-core-hop-limit-00 draft-ietf-core-hop-limit-01
Abstract Abstract
The presence of Constrained Application Protocol (CoAP) proxies may The presence of Constrained Application Protocol (CoAP) proxies may
lead to infinite forwarding loops, which is undesirable. To prevent lead to infinite forwarding loops, which is undesirable. To prevent
and detect such loops, this document specifies the Hop-Limit CoAP and detect such loops, this document specifies the Hop-Limit CoAP
option. option.
Status of This Memo Status of This Memo
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on March 21, 2019. This Internet-Draft will expire on May 10, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Hop-Limit Option . . . . . . . . . . . . . . . . . . . . . . 3 3. Hop-Limit Option . . . . . . . . . . . . . . . . . . . . . . 3
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
4.1. CoAP Response Code . . . . . . . . . . . . . . . . . . . 4 4.1. CoAP Response Code . . . . . . . . . . . . . . . . . . . 4
4.2. CoAP Option Number . . . . . . . . . . . . . . . . . . . 4 4.2. CoAP Option Number . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5 7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 5 7.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
More and more applications are using Constrained Application Protocol More and more applications are using Constrained Application Protocol
(CoAP) [RFC7252] as a communication protocol between involved (CoAP) [RFC7252] as a communication protocol between involved
application agents. For example, [I-D.ietf-dots-signal-channel] application agents. For example, [I-D.ietf-dots-signal-channel]
specifies how CoAP is used as a distributed denial-of-service (DDoS) specifies how CoAP is used as a distributed denial-of-service (DDoS)
attack signaling protocol seeking for help from DDoS mitigation attack signaling protocol seeking for help from DDoS mitigation
providers. In such contexts, a CoAP client can communicate directly providers. In such contexts, a CoAP client can communicate directly
with a server or indirectly via proxies. with a server or indirectly via proxies.
When multiple proxies are involved, infinite forwarding loops may be When multiple proxies are involved, infinite forwarding loops may be
experienced. To prevent such loops, this document defines a new CoAP experienced. To prevent such loops, this document defines a new CoAP
option, called Hop-Limit, which is inserted in particular by on-path option, called Hop-Limit (Section 3), which is inserted in particular
proxies. Also, the document defines a new CoAP Response Code to by on-path proxies. Also, the document defines a new CoAP Response
report loops together with relevant diagnostic information to ease Code (Section 4.1) to report loops together with relevant diagnostic
troubleshooting. information to ease troubleshooting.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in BCP
[RFC2119]. 14 [RFC2119][RFC8174] when, and only when, they appear in all
capitals, as shown here.
Readers should be familiar with the terms and concepts defined in Readers should be familiar with the terms and concepts defined in
[RFC7252]. [RFC7252].
Within this document, CoAP agent refers to both CoAP client and CoAP Within this document, CoAP agent refers to both CoAP client and CoAP
proxy. proxy.
3. Hop-Limit Option 3. Hop-Limit Option
Hop-Limit option (see Section 4.2) is an elective option used to Hop-Limit option (see Section 4.2) is an elective option used to
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Reached) error message SHOULD prepend its own information in the Reached) error message SHOULD prepend its own information in the
diagnostic payload with a space character used as separator. Only diagnostic payload with a space character used as separator. Only
one information per proxy SHOULD appear in the diagnostic payload. one information per proxy SHOULD appear in the diagnostic payload.
Doing so allows to limit the size of the TBA1 (Hop Limit Reached) Doing so allows to limit the size of the TBA1 (Hop Limit Reached)
error message, and to ease correlation with hops count. error message, and to ease correlation with hops count.
4. IANA Considerations 4. IANA Considerations
4.1. CoAP Response Code 4.1. CoAP Response Code
IANA is requested to add the following entries to the "CoAP Response IANA is requested to add the following entry to the "CoAP Response
Codes" sub-registry available at https://www.iana.org/assignments/ Codes" sub-registry available at https://www.iana.org/assignments/
core-parameters/core-parameters.xhtml#response-codes: core-parameters/core-parameters.xhtml#response-codes:
+------+------------------+-----------+ +------+------------------+-----------+
| Code | Description | Reference | | Code | Description | Reference |
+------+------------------+-----------+ +------+------------------+-----------+
| TBA1 | Hop Limit Reached| [RFCXXXX] | | TBA1 | Hop Limit Reached| [RFCXXXX] |
+------+------------------+-----------+ +------+------------------+-----------+
Table 1: CoAP Response Codes Table 1: CoAP Response Codes
This document suggests 5.06 as a code to be assigned for the new
response code.
Editorial Note: Please update TBA1 statements within the document
with the assigned code.
4.2. CoAP Option Number 4.2. CoAP Option Number
IANA is requested to add the following entry to the "CoAP Option IANA is requested to add the following entry to the "CoAP Option
Numbers" sub-registry available at https://www.iana.org/assignments/ Numbers" sub-registry available at https://www.iana.org/assignments/
core-parameters/core-parameters.xhtml#option-numbers: core-parameters/core-parameters.xhtml#option-numbers:
+--------+---+---+---+---+------------------+-----------+ +--------+---+---+---+---+------------------+-----------+
| Number | C | U | N | R | Name | Reference | | Number | C | U | N | R | Name | Reference |
+--------+---+---+---+---+------------------+-----------+ +--------+---+---+---+---+------------------+-----------+
| TBA2 | | | x | | Hop-Limit | [RFCXXXX] | | TBA2 | | | x | | Hop-Limit | [RFCXXXX] |
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained [RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252, Application Protocol (CoAP)", RFC 7252,
DOI 10.17487/RFC7252, June 2014, DOI 10.17487/RFC7252, June 2014,
<https://www.rfc-editor.org/info/rfc7252>. <https://www.rfc-editor.org/info/rfc7252>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
7.2. Informative References 7.2. Informative References
[I-D.ietf-dots-signal-channel] [I-D.ietf-dots-signal-channel]
Reddy, T., Boucadair, M., Patil, P., Mortensen, A., and N. K, R., Boucadair, M., Patil, P., Mortensen, A., and N.
Teague, "Distributed Denial-of-Service Open Threat Teague, "Distributed Denial-of-Service Open Threat
Signaling (DOTS) Signal Channel Specification", draft- Signaling (DOTS) Signal Channel Specification", draft-
ietf-dots-signal-channel-25 (work in progress), September ietf-dots-signal-channel-25 (work in progress), September
2018. 2018.
Authors' Addresses Authors' Addresses
Mohamed Boucadair Mohamed Boucadair
Orange Orange
Rennes 35000 Rennes 35000
France France
Email: mohamed.boucadair@orange.com Email: mohamed.boucadair@orange.com
Tirumaleswar Reddy Tirumaleswar Reddy
McAfee, Inc. McAfee, Inc.
Embassy Golf Link Business Park Embassy Golf Link Business Park
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