Extended TCP Options and IPv6 Extension Headers IPFIX Information Elements
draft-ietf-opsawg-ipfix-tcpo-v6eh-17
| Document | Type | Active Internet-Draft (opsawg WG) | |
|---|---|---|---|
| Authors | Mohamed Boucadair , Benoît Claise | ||
| Last updated | 2024-07-11 (Latest revision 2024-07-05) | ||
| Replaces | draft-boucadair-opsawg-ipfix-tcpo-v6eh | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | Proposed Standard | ||
| Formats | |||
| Reviews |
GENART Last Call review
(of
-11)
by Joel Halpern
Ready w/issues
INTDIR Early review
(of
-05)
by Dirk Von Hugo
Ready w/nits
TSVART Early review
(of
-05)
by Wesley Eddy
Ready w/issues
|
||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Thomas Graf | ||
| Shepherd write-up | Show Last changed 2024-04-08 | ||
| IESG | IESG state | IESG Evaluation::Revised I-D Needed | |
| Action Holders | |||
| Consensus boilerplate | Yes | ||
| Telechat date |
(None)
Has 2 DISCUSSes. Has enough positions to pass once DISCUSS positions are resolved. |
||
| Responsible AD | Mahesh Jethanandani | ||
| Send notices to | thomas.graf@swisscom.com | ||
| IANA | IANA review state | IANA OK - Actions Needed | |
| IANA expert review state | Expert Reviews OK | ||
| IANA expert review comments | The IPFIX Information Elements registrations have been approved. |
draft-ietf-opsawg-ipfix-tcpo-v6eh-17
OPSAWG M. Boucadair
Internet-Draft Orange
Intended status: Standards Track B. Claise
Expires: 6 January 2025 Huawei
5 July 2024
Extended TCP Options and IPv6 Extension Headers IPFIX Information
Elements
draft-ietf-opsawg-ipfix-tcpo-v6eh-17
Abstract
This document specifies new IP Flow Information Export (IPFIX)
Information Elements (IEs) to solve issues with existing
ipv6ExtensionHeaders and tcpOptions IPFIX IEs, especially the ability
to export any observed IPv6 extension headers or TCP options.
Discussion Venues
This note is to be removed before publishing as an RFC.
Discussion of this document takes place on the Operations and
Management Area Working Group Working Group mailing list
(opsawg@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/opsawg/.
Source for this draft and an issue tracker can be found at
https://github.com/boucadair/ipfix-tcpoptions-and-v6eh.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 6 January 2025.
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Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
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 publication of this document.
Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Issues with ipv6ExtensionHeaders Information Element . . 3
1.2. Issues with tcpOptions Information Element . . . . . . . 4
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 4
3. Information Elements for IPv6 Extension Headers . . . . . . . 5
3.1. ipv6ExtensionHeaderType Information Element . . . . . . . 5
3.2. ipv6ExtensionHeaderCount Information Element . . . . . . 5
3.3. ipv6ExtensionHeadersFull Information Element . . . . . . 6
3.4. ipv6ExtensionHeaderTypeCountList Information Element . . 7
3.5. ipv6ExtensionHeadersLimit Information Element . . . . . . 8
3.6. ipv6ExtensionHeadersChainLength Information Element . . . 9
3.7. ipv6ExtensionHeaderChainLengthList Information Element . 10
4. Information Elements for TCP Options . . . . . . . . . . . . 10
4.1. tcpOptionsFull Information Element . . . . . . . . . . . 10
4.2. tcpSharedOptionExID16 Information Element . . . . . . . . 11
4.3. tcpSharedOptionExID32 Information Element . . . . . . . . 12
4.4. tcpSharedOptionExID16List Information Element . . . . . . 13
4.5. tcpSharedOptionExID32List Information Element . . . . . . 13
5. Implementation and Operational Considerations . . . . . . . . 14
6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.1. IPv6 Extension Headers . . . . . . . . . . . . . . . . . 14
6.2. TCP Options . . . . . . . . . . . . . . . . . . . . . . . 15
6.2.1. Reduced-size Encoding . . . . . . . . . . . . . . . . 15
6.2.2. Shared Options . . . . . . . . . . . . . . . . . . . 16
7. Security Considerations . . . . . . . . . . . . . . . . . . . 17
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
8.1. Deprecate ipv6ExtensionHeaders and tcpOptions Information
Elements . . . . . . . . . . . . . . . . . . . . . . . . 17
8.2. IPFIX Information Elements . . . . . . . . . . . . . . . 18
8.3. IPFIX Information Element Data Type . . . . . . . . . . . 19
8.3.1. unsigned256 . . . . . . . . . . . . . . . . . . . . . 20
8.4. IPFIX Subregistry for IPv6 Extension Headers . . . . . . 20
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8.4.1. Initial Values . . . . . . . . . . . . . . . . . . . 21
8.4.2. Guidelines for the Designated Experts . . . . . . . . 23
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 23
9.1. Normative References . . . . . . . . . . . . . . . . . . 23
9.2. Informative References . . . . . . . . . . . . . . . . . 24
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 25
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 25
1. Introduction
This document specifies new IP Flow Information Export (IPFIX)
[RFC7011] Information Elements (IEs) to solve a set of issues
encountered with the specifications of ipv6ExtensionHeaders (to
export IPv6 extension headers) and tcpOptions (to export TCP options)
IEs [IANA-IPFIX]. More details about these issues are provided in
the following sub-sections.
1.1. Issues with ipv6ExtensionHeaders Information Element
The specification of the ipv6ExtensionHeaders IPFIX IE (64) does not:
* Cover the full extension headers' range defined in the IPv6
specification (Section 4 of [RFC8200]).
* Specify the procedure to follow when all bits are exhausted.
* Specify a means to export the order and the number of occurrences
of a given extension header.
* Specify how to automatically update the IANA IPFIX registry
([IANA-IPFIX]) when a new value is assigned in the IPv6 Extension
Header Types registry [IANA-EH]. Only a frozen set of extension
headers can be exported using the ipv6ExtensionHeaders IE. For
example, the ipv6ExtensionHeaders IE can't report some IPv6 EHs,
specifically EHs for Host Identity Protocol (139), Shim6 Protocol
(140) or extension headers for experimentation and testing.
* Specify whether the exported values match the full enclosed values
or only up to a limit imposed by hardware or software (e.g.,
Section 1.1 of [RFC8883]). Note that some implementations may not
be able to export all observed extension headers in a Flow because
of a hardware or software limit (see, e.g.,
[I-D.ietf-6man-eh-limits]). The specification of the
ipv6ExtensionHeaders IE does not discuss whether it covers all
enclosed extension headers or only up to a limit.
* Specify how to report the length of IPv6 extension headers.
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* Optimize the encoding.
* Explain the reasoning for reporting values which do not correspond
to extension headers (e.g., "Unknown Layer 4 header" or "Payload
compression header").
* Specify how to report extension header chains or aggregate
extension headers length.
Section 3 addresses these issues.
This specification deprecates the ipv6ExtensionHeaders IPFIX IE in
favor of the new IEs defined in this document.
1.2. Issues with tcpOptions Information Element
The specification of the tcpOptions IPFIX IE (209) does not:
* Describe how some observed TCP options in a Flow can be exported
using IPFIX. Only TCP options having a Kind <= 63 can be exported
in a tcpOptions IE.
* Allow reporting the observed Experiment Identifiers (ExIDs) that
are carried in shared Experimental TCP options (Kind=253 or 254)
[RFC6994].
* Optimize the encoding.
Section 4 addresses these issues.
This specification deprecates the tcpOptions IE in favor of the new
IEs defined in this document.
2. Conventions and Definitions
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.
This document uses the IPFIX-specific terminology (Information
Element, Template Record, Flow, etc.) defined in Section 2 of
[RFC7011]. As in the base IPFIX specification [RFC7011], these
IPFIX-specific terms have the first letter of a word capitalized.
Also, the document uses the terms defined in IPv6 [RFC8200] and TCP
[RFC9293] specifications.
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In addition, the document makes use of the following term:
Extension header chain: Refers to the chain of extension headers
that are present in an IPv6 packet.
This term should not be confused with the IPv6 header chain, which
includes the IPv6 header, zero or more IPv6 extension headers, and
zero or a single Upper-Layer Header.
Flow with varying extension header chain: Refers to a Flow where
distinct extension header chains are observed. Concretely,
different packets in such a Flow will have a different sequence of
extension header type codes.
3. Information Elements for IPv6 Extension Headers
3.1. ipv6ExtensionHeaderType Information Element
Name: ipv6ExtensionHeaderType
ElementID: TBD1
Description: Type of an IPv6 extension header observed in at least
one packet of this Flow.
Abstract Data Type: unsigned8
Data Type Semantics: identifier
Additional Information: See the IPv6 Extension Header Types registry
at [IANA-EH].
See Section 4 of [RFC8200] for the general definition of IPv6
extension headers.
Reference: This-Document
3.2. ipv6ExtensionHeaderCount Information Element
Name: ipv6ExtensionHeaderCount
ElementID: TBD2
Description: The number of consecutive occurrences of the same
extension header type in a Flow.
This IE is reported, e.g., in the ipv6ExtensionHeaderTypeCountList
IE.
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The type of the extension header is provided in the
ipv6ExtensionHeaderType IE.
Abstract Data Type: unsigned8
Data Type Semantics: totalCounter
Additional Information: See the IPv6 Extension Header Types registry
at [IANA-EH].
See Section 4 of [RFC8200] for the general definition of IPv6
extension headers.
Reference: This-Document
3.3. ipv6ExtensionHeadersFull Information Element
Name: ipv6ExtensionHeadersFull
ElementID: TBD3
Description: IPv6 extension headers observed in packets of this
Flow. The information is encoded in a set of bit fields. For
each IPv6 extension header, there is a bit in this set. The bit
is set to 1 if any observed packet of this Flow contains the
corresponding IPv6 extension header. Otherwise, if no observed
packet of this Flow contains the respective IPv6 extension header,
the value of the corresponding bit is 0.
The IPv6 extension header associated with each bit is provided in
[NEW_IPFIX_IPv6EH_SUBREGISTRY]. Bit 0 corresponds to the least-
significant bit in the ipv6ExtensionHeadersFull IE while bit 255
corresponds to the most-significant bit of the IE. In doing so,
few octets will be needed to encode common IPv6 extension headers
when observed in a Flow.
The "No Next Header" (bit 2) value (Section 4.7 of [RFC8200]) is
used if there is no upper-layer header in an IPv6 packet. Even if
the value is not considered as an extension header as such, the
corresponding bit is set in the ipv6ExtensionHeadersFull IE
whenever that value is encountered in the Flow.
Extension headers observed in a Flow with varying extension header
chain MUST NOT be grouped in the ipv6ExtensionHeadersFull IE if
the ipv6ExtensionHeaderChainLengthList IE is also present.
If the ipv6ExtensionHeaderChainLengthList IE is not present, then
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extension headers observed in a Flow with varying extension header
chain MAY be grouped in one single ipv6ExtensionHeadersFull IE or
be exported in separate ipv6ExtensionHeadersFull IEs, one for each
extension header chain.
The ipv6ExtensionHeadersFull IE MUST NOT be exported if
ipv6ExtensionHeaderTypeCountList IE is also present because of the
overlapping scopes between these two IEs.
The value of ipv6ExtensionHeadersFull IE may be encoded in fewer
octets per the guidelines in Section 6.2 of [RFC7011].
Abstract Data Type: unsigned256
Data Type Semantics: flags
Additional Information: See the ipv6ExtensionHeaders Bits registry
at [NEW_IPFIX_IPv6EH_SUBREGISTRY].
See the IPv6 Extension Header Types registry at [IANA-EH].
See Section 4 of [RFC8200] for the general definition of IPv6
extension headers.
Reference: This-Document
Note to the RFC Editor: Please replace
[NEW_IPFIX_IPv6EH_SUBREGISTRY] with the link to the
"ipv6ExtensionHeaders Bits" registry (Section 8.4).
3.4. ipv6ExtensionHeaderTypeCountList Information Element
Name: ipv6ExtensionHeaderTypeCountList
ElementID: TBD4
Description: As per Section 4.1 of [RFC8200], IPv6 nodes must accept
and attempt to process extension headers occurring any number of
times in the same packet. This IE echoes the order of extension
headers and number of consecutive occurrences of the same
extension header type in a Flow.
This IE is a subTemplateList of ipv6ExtensionHeaderType and
ipv6ExtensionHeaderCount IEs.
Each header chain in Flow with varying extension header chain MUST
be exported in a separate IE.
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The same extension header type may appear several times in an
ipv6ExtensionHeaderTypeCountList IE. For example, if an IPv6
packet of a Flow includes a Hop-by-Hop Options header, a
Destination Options header, a Fragment header, and Destination
Options header, the ipv6ExtensionHeaderTypeCountList IE will
report:
* the count of Hop-by-Hop Options headers,
* the occurrences of the Destination Options headers that are
observed before a Fragment header,
* the occurrences of the Fragment headers, and
* the occurrences of the Destination Options headers that are
observed right after a Fragment header.
If an implementation determines that an observed packet of a Flow
includes an extension header (including an extension header that
it does not support), then the exact observed code of that
extension header MUST be echoed in the
ipv6ExtensionHeaderTypeCountList IE. How an implementation
disambiguates between unknown upper-layer protocols vs. extension
headers is not IPFIX-specific. Refer, for example, to Section 2.2
of [RFC8883] for a behavior of an intermediate node that
encounters an unknown Next Header type.
Abstract Data Type: subTemplateList
Data Type Semantics: list
Additional Information: See the IPv6 Extension Header Types registry
at [IANA-EH].
See [RFC8200] for the general definition of IPv6 extension
headers.
Reference: This-Document
3.5. ipv6ExtensionHeadersLimit Information Element
Name: ipv6ExtensionHeadersLimit
ElementID: TBD5
Description: When set to "false", this IE indicates that the
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exported extension headers information (e.g.,
ipv6ExtensionHeadersFull or ipv6ExtensionHeaderTypeCountList) does
not match the full enclosed extension headers, but only up to a
limit that is typically set by hardware or software.
When set to "true", this IE indicates that the exported extension
header information matches the full enclosed extension headers.
Abstract Data Type: boolean
Data Type Semantics: default
Additional Information: See Section 4 of [RFC8200] for the general
definition of IPv6 extension headers.
See [RFC8883] for an example of IPv6 packet processing due to
limits on extension headers.
Reference: This-Document
3.6. ipv6ExtensionHeadersChainLength Information Element
Name: ipv6ExtensionHeadersChainLength
ElementID: TBD6
Description: In theory, there are no limits on the number of IPv6
extension headers that may be present in a packet other than the
path MTU. However, it was regularly reported that IPv6 packets
with extension headers are often dropped in the Internet.
As discussed in Section 1.2 of [RFC8883], some hardware devices
implement a parsing buffer of a fixed size to process packets,
including all the headers. When the aggregate length of headers
of an IPv6 packet exceeds that size, the packet will be discarded
or deferred to a slow path.
The ipv6ExtensionHeadersChainLength IE is used to report, in
octets, the length of an extension header chain observed in a
Flow. The length is the sum of the length of all extension
headers of the chain. Exporting such information might help
identifying root causes of performance degradation, including
packet drops.
Each header chain length of a Flow with varying extension header
chain MUST be exported in a separate
ipv6ExtensionHeadersChainLength IE.
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Abstract Data Type: unsigned32
Data Type Semantics: identifier
Units: octets
Additional Information: See Section 4 of [RFC8200] for the general
definition of IPv6 extension headers.
See [RFC9098] for an overview of operational implications of IPv6
packets with extension headers.
Reference: This-Document
3.7. ipv6ExtensionHeaderChainLengthList Information Element
Name: ipv6ExtensionHeaderChainLengthList
ElementID: TBD7
Description: This IE is used to report the chains and their length
as observed in a Flow with varying extension header chain.
This IE is a subTemplateList of ipv6ExtensionHeadersFull and
ipv6ExtensionHeadersChainLength IEs.
If several extension header chains are observed in a Flow, each
header chain MUST be exported in a separate
ipv6ExtensionHeaderChainLengthList IE.
Abstract Data Type: subTemplateList
Data Type Semantics: list
Additional Information: See the IPv6 Extension Header Types registry
at [IANA-EH].
See [RFC8200] for the general definition of IPv6 extension
headers.
Reference: This-Document
4. Information Elements for TCP Options
4.1. tcpOptionsFull Information Element
This section specifies a new IE to cover the full TCP options range.
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Name: tcpOptionsFull
ElementID: TBD8
Description: TCP options in packets of this Flow. The information
is encoded in a set of bit fields. For each TCP option, there is
a bit in this set. The bit is set to 1 if any observed packet of
this Flow contains the corresponding TCP option. Otherwise, if no
observed packet of this Flow contains the respective TCP option,
the value of the corresponding bit is 0.
Options are mapped to bits according to their option numbers. TCP
option Kind 0 corresponds to the least-significant bit in the
tcpOptionsFull IE while Kind 255 corresponds to the most-
significant bit of the IE. This approach allows an observer to
export any observed TCP option even if it does support that option
and without requiring updating a mapping table.
The value of tcpOptionsFull IE may be encoded in fewer octets per
the guidelines in Section 6.2 of [RFC7011].
The presence of tcpSharedOptionExID16List or
tcpSharedOptionExID32List IEs is an indication that a shared TCP
option (Kind=253 or 254) is observed in a Flow. The presence of
tcpSharedOptionExID16List or tcpSharedOptionExID32List IEs takes
precedence over setting the corresponding bits in the
tcpOptionsFull IE for the same Flow. In order to optimize the use
of the reduced-size encoding in the presence of
tcpSharedOptionExID16List or tcpSharedOptionExID32List IEs, the
Exporter MUST NOT set to 1 the shared TCP options (Kind=253 or
254) flags of the tcpOptionsFull IE that is reported for the same
Flow.
Abstract Data Type: unsigned256
Data Type Semantics: flags
Additional Information: See the TCP Option Kind Numbers registry at
[IANA-TCP].
See [RFC9293] for the general definition of TCP options.
Reference: This-Document
4.2. tcpSharedOptionExID16 Information Element
Name: tcpSharedOptionExID16
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ElementID: TBD9
Description: Reports an observed 2-byte ExID in a shared TCP option
(Kind=253 or 254) in a Flow.
A basicList of tcpSharedOptionExID16 is used to report
tcpSharedOptionExID16List values.
Abstract Data Type: unsigned16
Data Type Semantics: identifier
Additional Information: See the TCP Experimental Option Experiment
Identifiers (TCP ExIDs) registry at [IANA-TCP-EXIDs].
See [RFC9293] for the general definition of TCP options.
See [RFC6994] for the shared use of experimental TCP Options.
Reference: This-Document
4.3. tcpSharedOptionExID32 Information Element
Name: tcpSharedOptionExID32
ElementID: TBD10
Description: Reports an observed 4-byte ExID in a shared TCP option
(Kind=253 or 254) in a Flow.
A basicList of tcpSharedOptionExID32 is used to report
tcpSharedOptionExID32List values.
Abstract Data Type: unsigned32
Data Type Semantics: identifier
Additional Information: See the TCP Experimental Option Experiment
Identifiers (TCP ExIDs) registry at [IANA-TCP-EXIDs].
See [RFC9293] for the general definition of TCP options.
See [RFC6994] for the shared use of experimental TCP Options.
Reference: This-Document
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4.4. tcpSharedOptionExID16List Information Element
Name: tcpSharedOptionExID16List
ElementID: TBD11
Description: Reports observed 2-byte ExIDs in shared TCP options
(Kind=253 or 254) in a Flow.
A basicList of tcpSharedOptionExID16 IEs in which each
tcpSharedOptionExID16 IE carries an observed 2-byte ExID in a
shared option.
Abstract Data Type: basicList
Data Type Semantics: list
Additional Information: See the TCP Experimental Option Experiment
Identifiers (TCP ExIDs) registry at [IANA-TCP-EXIDs].
See [RFC9293] for the general definition of TCP options.
See [RFC6994] for the shared use of experimental TCP Options.
Reference: This-Document
4.5. tcpSharedOptionExID32List Information Element
Name: tcpSharedOptionExID32List
ElementID: TBD12
Description: Reports observed 4-byte ExIDs in shared TCP options
(Kind=253 or 254) in a Flow.
A basicList of tcpSharedOptionExID32 IEs in which each
tcpSharedOptionExID32 IE carries an observed 4-byte ExID in a
shared option.
Abstract Data Type: basicList
Data Type Semantics: list
Additional Information: See the TCP Experimental Option Experiment
Identifiers (TCP ExIDs) registry at [IANA-TCP-EXIDs].
See [RFC9293] for the general definition of TCP options.
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See [RFC6994] for the shared use of experimental TCP Options.
Reference: This-Document
5. Implementation and Operational Considerations
Implementations of tcpSharedOptionExID16, tcpSharedOptionExID32,
tcpSharedOptionExID16List, and tcpSharedOptionExID32List IEs are
assumed to be provided with a list of valid ExIDs [IANA-TCP-EXIDs].
How that list is maintained is implementation-specific. Absent that
list, an implementation can't autonomously determine whether an ExID
is present and, if so, whether it is 2- or 4-byte length.
If a TCP Flow contains packets with a mix of 2-byte and 4-byte ExIDs,
the same Template Record is used with both tcpSharedOptionExID16 and
tcpSharedOptionExID32 IEs.
6. Examples
This section provides a few examples to illustrate the use of some
IEs defined in this document.
6.1. IPv6 Extension Headers
Figure 1 provides an example of EH/bit mappings in an
ipv6ExtensionHeadersFull IE for an IPv6 Flow in which only the IPv6
Destination Options (0) header is observed. The bits are set
following the table provided in Section 8.4.1.
MSB LSB
1 25
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 ... 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+
|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0| |0|0|0|0|0|0|0|1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+
Figure 1: A First Example of EH/Bit Mappings in the
ipv6ExtensionHeadersFull IE
The leading zeros are dropped per the reduced-size encoding guidance.
One octet is thus sufficient to send these observed options on the
wire. Concretely, the ipv6ExtensionHeadersFull IE will be set to
0x01 (Figure 2).
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MSB LSB
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|0|0|0|0|0|0|0|1|
+-+-+-+-+-+-+-+-+
Figure 2: A First Example of ipv6ExtensionHeadersFull IE with
Reduced-size Encoding
Figure 3 provides another example of reported values in an
ipv6ExtensionHeadersFull IE for an IPv6 Flow in which the Destination
Options (0), IPv6 Hop-by-Hop Options (1), and Routing (5) headers are
observed. One octet is sufficient to report these observed options.
Concretely, the ipv6ExtensionHeadersFull IE will be set to 0x23.
MSB LSB
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|0|0|1|0|0|0|1|1|
+-+-+-+-+-+-+-+-+
Figure 3: A Second Example of ipv6ExtensionHeadersFull IE with
Reduced-size Encoding
Let us now consider an IPv6 Flow in which the following EH chain is
observed: Routing (5), Mobility (7), and Authentication (9) header.
Figure 4 shows the ipv6ExtensionHeadersFull IE (0x02A0) to reprot
this individual chain.
MSB LSB
1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0|0|0|0|0|1|0|1|0|1|0|0|0|0|0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: An Example of ipv6ExtensionHeadersFull IE Reported for
an Extension Header Chain
6.2. TCP Options
6.2.1. Reduced-size Encoding
Given TCP Kind allocation practices and the option mapping defined in
Section 4.1, fewer octets are likely to be used for Flows with common
TCP options.
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Figure 5 shows an example of Kind/bit mappings in a tcpOptionsFull IE
for a TCP Flow in which End of Option List (0), Maximum Segment Size
(2), and Window Scale (3) options are observed.
MSB LSB
1 25
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 ... 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+
|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0| |0|0|0|0|1|1|0|1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+
Figure 5: An Example of TCP Options / Bit Mappings in a
tcpOptionsFull IE
One octet is sufficient to report these observed options.
Concretely, the tcpOptionsFull IE will be set to 0x0D (Figure 6).
MSB LSB
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|0|0|0|0|1|1|0|1|
+-+-+-+-+-+-+-+-+
Figure 6: An Example of tcpOptionsFull IE with Reduced-size Encdoing
6.2.2. Shared Options
Let us consider a TCP Flow in which shared options with ExIDs 0x0348
(HOST_ID) [RFC7974], 0x454E (TCP-ENO) [RFC8547], and 0xE2D4C3D9
(Shared Memory communications over RMDA protocol) [RFC7609] are
observed. Figure 7 shows an excerpt of the Data Set encoding with a
focus on the tcpSharedOptionExID16 and tcpSharedOptionExID32 IEs.
The meaning of the fields is defined in [RFC6313].
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MSB LSB
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
: ... :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | List Length = 9 |semantic=allof |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|tcpSharedOptionExID16 = TBD9 | Field Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x0348 | 0x454E |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | List Length = 9 |semantic=allof |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|tcpSharedOptionExID32 = TBD10 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0xE2D4C3D9 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: ... :
Figure 7: Example of TCP Shared IEs
7. Security Considerations
IPFIX security considerations are discussed in Section 11 of
[RFC7011].
ipv6ExtensionHeadersChainLength and ipv6ExtensionHeadersLimit IEs can
be exploited by an unauthorized observer as a means to deduce the
processing capabilities of nodes. Section 8 of [RFC7012] discusses
the required measures to guarantee the integrity and confidentiality
of the exported information.
This document does not add new security considerations for exporting
IEs other than those already discussed in Section 8 of [RFC7012].
8. IANA Considerations
8.1. Deprecate ipv6ExtensionHeaders and tcpOptions Information Elements
This document requests IANA to update the "IPFIX Information
Elements" registry under the "IP Flow Information Export (IPFIX)
Entities" registry group [IANA-IPFIX] as follows:
* Update the ipv6ExtensionHeaders IE (64) entry by marking it as
deprecated in favor of the ipv6ExtensionHeadersFull IE defined in
this document. This note should also be echoed in the "Additional
Information" of the ipv6ExtensionHeaders IE.
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* Update the tcpOptions IE (209) entry by marking it as deprecated
in favor of the tcpOptionsFull IE defined in this document. This
note should also be echoed in the "Additional Information" of the
tcpOptions IE.
IANA is also requested to update the reference of
ipv6ExtensionHeaders IE (64) and tcpOptions IE (209) to point to this
document.
8.2. IPFIX Information Elements
This document requests IANA to add the following new IPFIX IEs to the
"IPFIX Information Elements" registry under the "IP Flow Information
Export (IPFIX) Entities" registry group [IANA-IPFIX]:
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+=======+====================================+================+
| Value | Name | Reference |
+=======+====================================+================+
| TBD1 | ipv6ExtensionHeader | Section 3.1 of |
| | | This-Document |
+-------+------------------------------------+----------------+
| TBD2 | ipv6ExtensionHeaderCount | Section 3.2 of |
| | | This-Document |
+-------+------------------------------------+----------------+
| TBD3 | ipv6ExtensionHeadersFull | Section 3.3 of |
| | | This-Document |
+-------+------------------------------------+----------------+
| TBD4 | ipv6ExtensionHeaderTypeCountList | Section 3.4 of |
| | | This-Document |
+-------+------------------------------------+----------------+
| TBD5 | ipv6ExtensionHeadersLimit | Section 3.5 of |
| | | This-Document |
+-------+------------------------------------+----------------+
| TBD6 | ipv6ExtensionHeadersChainLength | Section 3.6 of |
| | | This-Document |
+-------+------------------------------------+----------------+
| TBD7 | ipv6ExtensionHeaderChainLengthList | Section 3.7 of |
| | | This-Document |
+-------+------------------------------------+----------------+
| TBD8 | tcpOptionsFull | Section 4.1 of |
| | | This-Document |
+-------+------------------------------------+----------------+
| TBD9 | tcpSharedOptionExID16 | Section 4.2 of |
| | | This-Document |
+-------+------------------------------------+----------------+
| TBD10 | tcpSharedOptionExID32 | Section 4.3 of |
| | | This-Document |
+-------+------------------------------------+----------------+
| TBD11 | tcpSharedOptionExID16List | Section 4.4 of |
| | | This-Document |
+-------+------------------------------------+----------------+
| TBD12 | tcpSharedOptionExID32List | Section 4.5 of |
| | | This-Document |
+-------+------------------------------------+----------------+
Table 1: New IPFIX Information Elements
8.3. IPFIX Information Element Data Type
This document requests IANA to add the following new abstract data
type to the "IPFIX Information Element Data Types" registry under the
"IP Flow Information Export (IPFIX) Entities" registry group
[IANA-IPFIX]:
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+=======+=============+===============+
| Value | Description | Reference |
+=======+=============+===============+
| TBD10 | unsigned256 | This-Document |
+-------+-------------+---------------+
Table 2: New IPFIX Information
Element Data Type
8.3.1. unsigned256
The type "unsigned256" represents a non-negative integer value in the
range of '0' to '2^256 - 1'. Similar to Section 6.1.1 of [RFC7011],
this type MUST be encoded using the default canonical format in
network byte order.
Reduced-Size encoding (Section 6.2 of [RFC7011]) applies to this data
type. The reduction in size can be to any number of octets smaller
than the unsigned256 type if the data value still fits, i.e., so that
only leading zeroes are dropped.
8.4. IPFIX Subregistry for IPv6 Extension Headers
This document requests IANA to create a new registry entitled
"ipv6ExtensionHeaders Bits" under the IANA IPFIX registry group
[IANA-IPFIX].
When a new code is assigned to an IPv6 EH in [IANA-EH], the next
available free bit is selected by IANA for this EH from
"ipv6ExtensionHeaders Bits" registry and the registry is updated with
the details that mirror the assigned EH. The "Label" mirrors the
"keyword" of an EH as indicated in [IANA-Protocols], while the
"Protocol Number" mirrors the "Protocol Number" in [IANA-EH]. IANA
is requested to add the following note to [IANA-EH]:
Note: When a new code is assigned to an IPv6 Extension Header,
the next available free bit in [NEW_IPFIX_IPv6EH_SUBREGISTRY]
is selected for this new Extension Header.
[NEW_IPFIX_IPv6EH_SUBREGISTRY] is updated accordingly.
Modifications to existing registrations must be mirrored in
[NEW_IPFIX_IPv6EH_SUBREGISTRY].
Note to the RFC Editor: Please replace
[NEW_IPFIX_IPv6EH_SUBREGISTRY] with the link used by IANA for this
new registry.
Otherwise, the registration policy for the registry is Expert Review
(Section 4.5 of [RFC8126]). See more details in Section 8.4.2.
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8.4.1. Initial Values
The initial values of this registry are provided in Table 3.
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+=====+=======+==========+=========================+===============+
| Bit | Label | Protocol | Description | Reference |
| | | Number | | |
+=====+=======+==========+=========================+===============+
| 0 | DST | 60 | Destination Options for | This-Document |
| | | | IPv6 | |
+-----+-------+----------+-------------------------+---------------+
| 1 | HOP | 0 | IPv6 Hop-by-Hop Options | This-Document |
+-----+-------+----------+-------------------------+---------------+
| 2 | NoNxt | 59 | No Next Header for IPv6 | This-Document |
+-----+-------+----------+-------------------------+---------------+
| 3 | UNK | | Unknown extension or | This-Document |
| | | | transport header | |
+-----+-------+----------+-------------------------+---------------+
| 4 | FRA0 | 44 | Fragment header - first | This-Document |
| | | | fragment | |
+-----+-------+----------+-------------------------+---------------+
| 5 | RH | 43 | Routing header | This-Document |
+-----+-------+----------+-------------------------+---------------+
| 6 | FRA1 | 44 | Fragmentation header - | This-Document |
| | | | not first fragment | |
+-----+-------+----------+-------------------------+---------------+
| 7 | MOB | 135 | Mobility Header | This-Document |
+-----+-------+----------+-------------------------+---------------+
| 8 | ESP | 50 | Encapsulating Security | This-Document |
| | | | Payload | |
+-----+-------+----------+-------------------------+---------------+
| 9 | AH | 51 | Authentication Header | This-Document |
+-----+-------+----------+-------------------------+---------------+
| 10 | HIP | 139 | Host Identity Protocol | This-Document |
+-----+-------+----------+-------------------------+---------------+
| 11 | SHIM6 | 140 | Shim6 Protocol | This-Document |
+-----+-------+----------+-------------------------+---------------+
| 12 | | 253 | Use for experimentation | This-Document |
| | | | and testing | |
+-----+-------+----------+-------------------------+---------------+
| 13 | | 254 | Use for experimentation | This-Document |
| | | | and testing | |
+-----+-------+----------+-------------------------+---------------+
| 14 | | | Unassigned | |
| to | | | | |
| 255 | | | | |
+-----+-------+----------+-------------------------+---------------+
Table 3: Initial Values of the IPv6 Extension Headers IPFIX
Subregistry
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8.4.2. Guidelines for the Designated Experts
It is suggested that multiple designated experts be appointed for
registry change requests.
Designated experts are solicited only for changes that are not
covered by the automatic mirroring described above. For example, a
registration may request two bits for a new EH to cover specific
behaviors or uses of that EH.
Criteria that should be applied by the designated experts include
determining whether the proposed registration duplicates existing
entries, whether the exception to the automatic mirroring procedure
is justified, and whether the registration description is clear and
fits the purpose of this registry.
Within the review period, the designated experts will either approve
or deny the registration request, communicating this decision to the
IANA. Denials should include an explanation and, if applicable,
suggestions as to how to make the request successful.
9. References
9.1. Normative References
[IANA-EH] IANA, "Internet Protocol Version 6 (IPv6) Parameters, IPv6
Extension Header Types",
<https://www.iana.org/assignments/ipv6-parameters/ipv6-
parameters.xhtml#extension-header>.
[IANA-IPFIX]
IANA, "IP Flow Information Export (IPFIX) Entities",
<https://www.iana.org/assignments/ipfix/ipfix.xhtml>.
[IANA-Protocols]
IANA, "Protocol Numbers",
<https://www.iana.org/assignments/protocol-numbers/
protocol-numbers.xhtml>.
[IANA-TCP] IANA, "Transmission Control Protocol (TCP) Parameters, TCP
Option Kind Numbers", <https://www.iana.org/assignments/
tcp-parameters/tcp-parameters.xhtml#tcp-parameters-1>.
[IANA-TCP-EXIDs]
IANA, "Transmission Control Protocol (TCP) Parameters, TCP
Experimental Option Experiment Identifiers (TCP ExIDs)",
<https://www.iana.org/assignments/tcp-parameters/tcp-
parameters.xhtml#tcp-exids>.
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[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/rfc/rfc2119>.
[RFC6313] Claise, B., Dhandapani, G., Aitken, P., and S. Yates,
"Export of Structured Data in IP Flow Information Export
(IPFIX)", RFC 6313, DOI 10.17487/RFC6313, July 2011,
<https://www.rfc-editor.org/rfc/rfc6313>.
[RFC6994] Touch, J., "Shared Use of Experimental TCP Options",
RFC 6994, DOI 10.17487/RFC6994, August 2013,
<https://www.rfc-editor.org/rfc/rfc6994>.
[RFC7011] Claise, B., Ed., Trammell, B., Ed., and P. Aitken,
"Specification of the IP Flow Information Export (IPFIX)
Protocol for the Exchange of Flow Information", STD 77,
RFC 7011, DOI 10.17487/RFC7011, September 2013,
<https://www.rfc-editor.org/rfc/rfc7011>.
[RFC7012] Claise, B., Ed. and B. Trammell, Ed., "Information Model
for IP Flow Information Export (IPFIX)", RFC 7012,
DOI 10.17487/RFC7012, September 2013,
<https://www.rfc-editor.org/rfc/rfc7012>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/rfc/rfc8126>.
[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/rfc/rfc8174>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/rfc/rfc8200>.
[RFC9293] Eddy, W., Ed., "Transmission Control Protocol (TCP)",
STD 7, RFC 9293, DOI 10.17487/RFC9293, August 2022,
<https://www.rfc-editor.org/rfc/rfc9293>.
9.2. Informative References
[I-D.ietf-6man-eh-limits]
Herbert, T., "Limits on Sending and Processing IPv6
Extension Headers", Work in Progress, Internet-Draft,
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draft-ietf-6man-eh-limits-13, 12 June 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-6man-eh-
limits-13>.
[RFC7609] Fox, M., Kassimis, C., and J. Stevens, "IBM's Shared
Memory Communications over RDMA (SMC-R) Protocol",
RFC 7609, DOI 10.17487/RFC7609, August 2015,
<https://www.rfc-editor.org/rfc/rfc7609>.
[RFC7974] Williams, B., Boucadair, M., and D. Wing, "An Experimental
TCP Option for Host Identification", RFC 7974,
DOI 10.17487/RFC7974, October 2016,
<https://www.rfc-editor.org/rfc/rfc7974>.
[RFC8547] Bittau, A., Giffin, D., Handley, M., Mazieres, D., and E.
Smith, "TCP-ENO: Encryption Negotiation Option", RFC 8547,
DOI 10.17487/RFC8547, May 2019,
<https://www.rfc-editor.org/rfc/rfc8547>.
[RFC8883] Herbert, T., "ICMPv6 Errors for Discarding Packets Due to
Processing Limits", RFC 8883, DOI 10.17487/RFC8883,
September 2020, <https://www.rfc-editor.org/rfc/rfc8883>.
[RFC9098] Gont, F., Hilliard, N., Doering, G., Kumari, W., Huston,
G., and W. Liu, "Operational Implications of IPv6 Packets
with Extension Headers", RFC 9098, DOI 10.17487/RFC9098,
September 2021, <https://www.rfc-editor.org/rfc/rfc9098>.
Acknowledgments
Thanks to Paul Aitken, Éric Vyncke, and Joe Touch for the reviews and
comments. Special thanks to Andrew Feren for sharing data about
scans of IPFIX data he collected.
Thanks to Wesley Eddy for the tsvart review, Yingzhen Qu for the
opsdir review, Dirk Von Hugo for intdir review, Joel Halpern for the
genart review, and Tero Kivinen for the secdir review.
Thanks to Thomas Graf for the Shepherd review.
Thanks to Mahesh Jethanandani for the AD review.
Thanks to Éric Vyncke for the IESG review.
Authors' Addresses
Mohamed Boucadair
Orange
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Email: mohamed.boucadair@orange.com
Benoit Claise
Huawei
Email: benoit.claise@huawei.com
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