XEP-0468: WebSocket S2S

Abstract
This specification defines a procedure to make s2s XMPP connections over WebSocket.
Author
Travis Burtrum
Copyright
© 2022 – 2022 XMPP Standards Foundation. SEE LEGAL NOTICES.
Status

Experimental

WARNING: This Standards-Track document is Experimental. Publication as an XMPP Extension Protocol does not imply approval of this proposal by the XMPP Standards Foundation. Implementation of the protocol described herein is encouraged in exploratory implementations, but production systems are advised to carefully consider whether it is appropriate to deploy implementations of this protocol before it advances to a status of Draft.
Type
Standards Track
Version
0.1.0 (2022-07-13)
Document Lifecycle
  1. Experimental
  2. Proposed
  3. Stable
  4. Final

1. Introduction

RFC 7395 [1] specifies how to make c2s connections over WebSocket. This XEP extends that to also support s2s connections over WebSocket.

2. Requirements

Everything mentioned in RFC 7395 [1] should be followed with the following changes:

  1. Connection details are discovered by using Discovering Alternative XMPP Connection Methods (XEP-0156) [2]
  2. For c2s, RFC 7395 [1] requires replacing the 'jabber:client' namespace with 'urn:ietf:params:xml:ns:xmpp-framing', for s2s, the 'jabber:server' namespace should be replaced with 'urn:ietf:params:xml:ns:xmpp-framing-server'.
  3. wss (TLS) upgraded to a MUST be used, therefore SASL EXTERNAL authentication can be used as defined in XMPP Core [3]

3. Use Cases

Some hosting services only allow HTTPS proxies to access servers, meaning federating XMPP servers cannot be ran on these hosts unless s2s is accessible over HTTPS.

4. Security Considerations

Identical to RFC 7395 Security Considerations.

5. IANA Considerations

A URN sub-namespace for framing of s2s Extensible Messaging and Presence Protocol (XMPP) streams is defined as follows.

URI: urn:ietf:params:xml:ns:xmpp-framing-server

Specification: this document

Registrant Contact: IESG <iesg@ietf.org>

6. XMPP Registrar Considerations

This document requires no interaction with the XMPP Registrar [4].

Appendices

Appendix A: Document Information

Series
XEP
Number
0468
Publisher
XMPP Standards Foundation
Status
Experimental
Type
Standards Track
Version
0.1.0
Last Updated
2022-07-13
Approving Body
XMPP Council
Dependencies
XMPP Core, XEP-0156
Supersedes
None
Superseded By
None
Short Name
NOT_YET_ASSIGNED
Source Control
HTML

This document in other formats: XML  PDF

Appendix B: Author Information

Travis Burtrum
Email
travis@burtrum.org
JabberID
travis@burtrum.org

Copyright

This XMPP Extension Protocol is copyright © 1999 – 2024 by the XMPP Standards Foundation (XSF).

Permissions

Permission is hereby granted, free of charge, to any person obtaining a copy of this specification (the "Specification"), to make use of the Specification without restriction, including without limitation the rights to implement the Specification in a software program, deploy the Specification in a network service, and copy, modify, merge, publish, translate, distribute, sublicense, or sell copies of the Specification, and to permit persons to whom the Specification is furnished to do so, subject to the condition that the foregoing copyright notice and this permission notice shall be included in all copies or substantial portions of the Specification. Unless separate permission is granted, modified works that are redistributed shall not contain misleading information regarding the authors, title, number, or publisher of the Specification, and shall not claim endorsement of the modified works by the authors, any organization or project to which the authors belong, or the XMPP Standards Foundation.

Disclaimer of Warranty

## NOTE WELL: This Specification is provided on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. ##

Limitation of Liability

In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall the XMPP Standards Foundation or any author of this Specification be liable for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising from, out of, or in connection with the Specification or the implementation, deployment, or other use of the Specification (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if the XMPP Standards Foundation or such author has been advised of the possibility of such damages.

IPR Conformance

This XMPP Extension Protocol has been contributed in full conformance with the XSF's Intellectual Property Rights Policy (a copy of which can be found at <https://xmpp.org/about/xsf/ipr-policy> or obtained by writing to XMPP Standards Foundation, P.O. Box 787, Parker, CO 80134 USA).

Visual Presentation

The HTML representation (you are looking at) is maintained by the XSF. It is based on the YAML CSS Framework, which is licensed under the terms of the CC-BY-SA 2.0 license.

Appendix D: Relation to XMPP

The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 6120) and XMPP IM (RFC 6121) specifications contributed by the XMPP Standards Foundation to the Internet Standards Process, which is managed by the Internet Engineering Task Force in accordance with RFC 2026. Any protocol defined in this document has been developed outside the Internet Standards Process and is to be understood as an extension to XMPP rather than as an evolution, development, or modification of XMPP itself.

Appendix E: Discussion Venue

The primary venue for discussion of XMPP Extension Protocols is the <standards@xmpp.org> discussion list.

Discussion on other xmpp.org discussion lists might also be appropriate; see <https://xmpp.org/community/> for a complete list.

Errata can be sent to <editor@xmpp.org>.

Appendix F: Requirements Conformance

The following requirements keywords as used in this document are to be interpreted as described in RFC 2119: "MUST", "SHALL", "REQUIRED"; "MUST NOT", "SHALL NOT"; "SHOULD", "RECOMMENDED"; "SHOULD NOT", "NOT RECOMMENDED"; "MAY", "OPTIONAL".

Appendix G: Notes

1. RFC 7395: An Extensible Messaging and Presence Protocol (XMPP) Subprotocol for WebSocket <http://tools.ietf.org/html/rfc7395>.

2. XEP-0156: Discovering Alternative XMPP Connection Methods <https://xmpp.org/extensions/xep-0156.html>.

3. RFC 6120: Extensible Messaging and Presence Protocol (XMPP): Core <http://tools.ietf.org/html/rfc6120>.

4. The XMPP Registrar maintains a list of reserved protocol namespaces as well as registries of parameters used in the context of XMPP extension protocols approved by the XMPP Standards Foundation. For further information, see <https://xmpp.org/registrar/>.

Appendix H: Revision History

Note: Older versions of this specification might be available at https://xmpp.org/extensions/attic/

  1. Version 0.1.0 (2022-07-13)
    Accepted by vote of Council on 2022-06-22.
    XEP Editor (jsc)
  2. Version 0.0.1 (2022-06-13)

    First draft.

    tjb

Appendix I: Bib(La)TeX Entry

@report{burtrum2022xep0468,
  title = {WebSocket S2S},
  author = {Burtrum, Travis},
  type = {XEP},
  number = {0468},
  version = {0.1.0},
  institution = {XMPP Standards Foundation},
  url = {https://xmpp.org/extensions/xep-0468.html},
  date = {2022-06-13/2022-07-13},
}

END