Flow Identity Extension for HELD

Abstract

RFC 6155 specifies an extension for the HTTP-Enabled Location Delivery (HELD) Protocol allowing the use of an IP address and port number to request a Device location based on an individual packet flow.

However, certain kinds of NAT require that identifiers for both ends of the packet flow must be specified in order to unambiguously satisfy the location request.

This document specifies an XML Schema and URN Sub-Namespace for a Flow Identity Extension for HELD to support this requirement.

This document updates RFC 6155 by deprecating the port number elements specified therein.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

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This Internet-Draft will expire on December 25, 2016.

Copyright Notice

Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved.

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Table of Contents

• 1. Introduction
• 2. Conventions used in this document
• 3. Usage
• 4. XML Schema
• 5. IANA Considerations
• 5.1. URN Sub-Namespace Registration for urn:ietf:params:xml:ns:geopriv:held:flow
• 5.2. XML Schema Registration
• 6. Privacy Considerations
• 7. Security Considerations
• 8. Acknowledgements
• 9. Notes to the RFC Editor (to be removed)
• 10. References
• 10.1. Normative References
• 10.2. Informative References
• Author's Address

1. Introduction

Work at the Emergency Location Task Group of NICC Standards Ltd (the UK's telecoms industry standards body) prompted the addition of Port Number identifiers in HELD Identity [RFC6155] to allow HELD [RFC5985] requests for target Devices that are behind a NAT device.

Subsequent analysis has determined that in the presence of particular types of NAT device, and in particular Carrier Grade NATs, it is necessary to know the complete tuple of (layer 3 protocol, layer 4 protocol, source address, source port, destination address, destination port) in order to unambiguously identify a flow, and therefore the true target Device.

This document specifies an XML Schema and URN Sub-Namespace for a Flow Identity Extension to support this requirement.

Since the Location Recipient may not know in advance whether the Target is behind a NAT device the port number elements from Section 3.3 of [RFC6155] are deprecated and MUST NOT be used. This document provides a more generally applicable means of identifying a Device based on the parameters of a network flow of which it is an endpoint.

2. Conventions used in this document

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 [RFC2119].

3. Usage

An example HELD request is shown below:

<locationRequest xmlns="urn:ietf:params:xml:ns:geopriv:held"
                      responseTime="8">
  <locationType exact="true">geodetic</locationType>
  <flow xmlns="urn:ietf:params:xml:ns:geopriv:held:flow"
    layer4="tcp" layer3="ipv4">
    <src>
      <address>192.168.1.1</address>
      <port>1024</port>
    </src>
    <dst>
      <address>10.0.0.1</address>
      <port>80</port>
    </dst>
  </flow>
</locationRequest>
          

The <flow> element MUST contain:

• a "layer3" attribute with a value of "ipv4" or "ipv6".
• a "layer4" attribute with a value of "udp" [RFC0768], "tcp" [RFC0793], "sctp" [RFC4960], "dccp" [RFC4340], or a decimal integer representing any applicable protocol from the IANA Assigned Internet Protocol Numbers Registry.

and MAY optionally contain:

• a "target" attribute with a value of "src" (default) or "dst" to indicate which end of the flow is the Target of the <locationRequest> with respect to the HELD protocol.

4. XML Schema

<?xml version="1.0" encoding="UTF-8"?>
<xs:schema targetNamespace="urn:ietf:params:xml:ns:geopriv:held:flow"
  xmlns:xs="http://www.w3.org/2001/XMLSchema"
  xmlns:flow="urn:ietf:params:xml:ns:geopriv:held:flow"
  elementFormDefault="qualified">

  <xs:annotation>
    <xs:appinfo
      source="urn:ietf:params:xml:schema:geopriv:held:flow">
      HELD Flow Identity</xs:appinfo>
    <xs:documentation
      source="http://www.rfc-editor.org/rfc/rfcNEW1.txt">
      This document defines Flow Identity elements for HELD.
    </xs:documentation>
  </xs:annotation>

  <xs:element name="flow" type="flow:flowIdentity"/>

  <xs:complexType name="flowIdentity">
    <xs:sequence>
      <xs:element name="src" type="flow:flowEndpoint"/>
      <xs:element name="dst" type="flow:flowEndpoint"/>
    </xs:sequence>
    <xs:attribute name="target" default="src">
      <xs:simpleType>
        <xs:restriction base="xs:token">
          <xs:pattern value="(src|dst)"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="layer3" use="required">
      <xs:simpleType>
        <xs:restriction base="xs:token">
          <xs:pattern value="(ipv4|ipv6)"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="layer4" use="required">
      <xs:simpleType>
        <xs:restriction base="xs:token">
          <xs:pattern value="(udp|tcp|sctp|dccp|\d+)"/>
        </xs:restriction>
      </xs:simpleType>
    </xs:attribute>
  </xs:complexType>

  <xs:complexType name="flowEndpoint">
    <xs:all>
      <xs:element name="address">
        <xs:simpleType>
          <xs:restriction base="xs:token"/>
        </xs:simpleType>
      </xs:element>
      <xs:element name="port">
        <xs:simpleType>
          <xs:restriction base="xs:unsignedShort">
            <xs:minInclusive value="1"/>
          </xs:restriction>
        </xs:simpleType>
      </xs:element>
    </xs:all>
  </xs:complexType>
</xs:schema>

5. IANA Considerations

5.1. URN Sub-Namespace Registration for urn:ietf:params:xml:ns:geopriv:held:flow

This section registers a new XML namespace, "urn:ietf:params:xml:ns:geopriv:held:flow", as per the guidelines in [RFC3688].

URI: urn:ietf:params:xml:ns:geopriv:held:flow

Registrant Contact: IETF GEOPRIV Working Group (geopriv@ietf.org), Ray Bellis (ray.bellis@nominet.org.uk)

XML:

BEGIN
  <?xml version="1.0"?>
  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
  <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
    <head>
      <title>HELD Flow Identity Parameters</title>
    </head>
    <body>
      <h1>Namespace for HELD Flow Identity Parameters</h1>
      <h2>urn:ietf:params:xml:ns:geopriv:held:flow</h2>
      <p>See <a href="http://www.rfc-editor.org/rfc/rfcNEW1.txt">
         RFC NEW1</a>.</p>
    </body>
  </html>
END

5.2. XML Schema Registration

This section registers an XML schema as per the guidelines in [RFC3688]

URI: urn:ietf:params:xml:ns:geopriv:held:flow

Registrant Contact: IETF GEOPRIV Working Group (geopriv@ietf.org), Ray Bellis (ray.bellis@nominet.org.uk)

Schema: The XML for this schema can be found as the entirety of Section 4 of this document.

6. Privacy Considerations

This document introduces no new privacy considerations beyond those in [RFC6155]

7. Security Considerations

This document introduces no new security considerations beyond those in [RFC6155]

8. Acknowledgements

The author wishes to thank the members of the NICC Emergency Location Task Group, the IETF GeoPriv Working Group, and the authors of [RFC6155], from which the text for the URN and XML Schema Registrations were derived.

9. Notes to the RFC Editor (to be removed)

References to "NEW1" need to be replaced with this document's final RFC number.

10. References

10.1. Normative References

10.2. Informative References

Author's Address