IDR Working Group D. McPherson
Internet-Draft Verisign, Inc.
Intended status: Standards Track R. Raszuk, Ed.
Expires: September 20, 2016 Bloomberg LP
B. Pithawala
Individual
A. Karch
Cisco Systems
S. Hares, Ed.
Huawei
March 19, 2016
Dissemination of Flow Specification Rules for IPv6
draft-ietf-idr-flow-spec-v6-07.txt
Abstract
Dissemination of Flow Specification Rules [RFC5575] provides a
protocol extension for propagation of traffic flow information for
the purpose of rate limiting or filtering. The [RFC5575] specifies
those extensions for IPv4 protocol data packets.
This specification extends the current [RFC5575] and defines changes
to the original document in order to make it also usable and
applicable to IPv6 data packets.
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
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Drafts is at http://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 September 20, 2016.
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Copyright Notice
Copyright (c) 2016 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
(http://trustee.ietf.org/license-info) in effect on the date of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. IPv6 Flow Specification encoding in BGP . . . . . . . . . . . 3
3. IPv6 Flow Specification types changes . . . . . . . . . . . . 3
3.1. Order of Traffic Filtering Rules . . . . . . . . . . . . 5
4. IPv6 Flow Specification Traffic Filtering Action changes . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
8.1. Normative References . . . . . . . . . . . . . . . . . . 8
8.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
The growing amount of IPv6 traffic in private and public networks
requires the extension of tools used in the IPv4 only networks to be
also capable of supporting IPv6 data packets.
In this document authors analyze the differences of IPv6 [RFC2460]
flows description from those of traditional IPv4 packets and propose
subset of new encoding formats to enable Dissemination of Flow
Specification Rules [RFC5575] for IPv6.
This specification should be treated as an extension of base
[RFC5575] specification and not its replacement. It only defines the
delta changes required to support IPv6 while all other definitions
and operation mechanisms of Dissemination of Flow Specification Rules
will remain in the main specification and will not be repeated here.
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2. IPv6 Flow Specification encoding in BGP
The [RFC5575] defines a new SAFIs (133 for IPv4) and (134 for VPNv4)
applications in order to carry corresponding to each such application
flow specification.
This document will redefine the [RFC5575] SAFIs in order to make them
AFI specific and applicable to both IPv4 and IPv6 applications.
The following changes are defined:
"SAFI 133 for IPv4 dissemination of flow specification rules" to
now be defined as "SAFI 133 for dissemination of unicast flow
specification rules"
"SAFI 134 for VPNv4 dissemination of flow specification rules" to
now be defined as "SAFI 134 for dissemination of L3VPN flow
specification rules"
For both SAFIs the indication to which address family they are
referring to will be recognized by AFI value (AFI=1 for IPv4 or
VPNv4, AFI=2 for IPv6 and VPNv6 respectively). Such modification is
fully backwards compatible with existing implementation and
production deployments.
It needs to be observed that such choice of proposed encoding is
compatible with filter validation against routing reachability
information as described in section 6 of RFC5575. Validation tables
will now be performed according to the following rules.
Flow specification received over AFI/SAFI=1/133 will be validated
against routing reachability received over AFI/SAFI=1/1
Flow specification received over AFI/SAFI=1/134 will be validated
against routing reachability received over AFI/SAFI=1/128
Flow specification received over AFI/SAFI=2/133 will be validated
against routing reachability received over AFI/SAFI=2/1
Flow specification received over AFI/SAFI=2/134 will be validated
against routing reachability received over AFI/SAFI=2/128
3. IPv6 Flow Specification types changes
The following component types are redefined or added for the purpose
of accommodating new IPv6 header encoding. Unless otherwise stated
all other types as defined in [RFC5575] apply to IPv6 packets as is.
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Type 1 - Destination IPv6 Prefix
Encoding: <type (1 octet), prefix length (1 octet), prefix
offset (1 octet), prefix>
Function: Defines the destination prefix to match. Prefix
offset has been defined to allow for flexible matching on part
of the IPv6 address where we want to skip (don't care) of N
first bits of the address. This can be especially useful where
part of the IPv6 address consists of an embedded IPv4 address
and matching needs to happen only on the embedded IPv4 address.
The encoded prefix contains enough octets for the bits used in
matching (length minus offset bits).
Type 2 - Source IPv6 Prefix
Encoding: <type (1 octet), prefix length (1 octet), prefix
offset (1 octet), prefix>
Function: Defines the source prefix to match. Prefix offset
has been defined to allow for flexible matching on part of the
IPv6 address where we want to skip (don't care) of N first bits
of the address. This can be especially useful where part of
the IPv6 address consists of an embedded IPv4 address and
matching needs to happen only on the embedded IPv4 address.
The encoded prefix contains enough octets for the bits used in
matching (length minus offset bits)
Type 3 - Next Header
Encoding: <type (1 octet), [op, value]+>
Function: Contains a set of {operator, value} pairs that are
used to match the last Next Header value octet in IPv6 packets.
The operator byte is encoded as specified in component type 3
of [RFC5575].
Note: While IPv6 allows for more then one Next Header field in
the packet the main goal of Type 3 flow specification component
is to match on the subsequent IP protocol value. Therefor the
definition is limited to match only on last Next Header field
in the packet.
Type 12 - Fragment
Encoding: <type (1 octet), [op, bitmask]+>
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Uses bitmask operand format defined above. Bit-7 is not used
and MUST be 0 to provide backwards-compatibility with the
definition in [RFC5575]
Bitmast operand format:
0 1 2 3 4 5 6 7
+---+---+---+---+---+---+---+---+
| Reserved |LF |FF |IsF| 0 |
+---+---+---+---+---+---+---+---+
Bitmask values:
+ Bit 6 - Is a fragment (IsF)
+ Bit 5 - First fragment (FF)
+ Bit 4 - Last fragment (LF)
Type 13 - Flow Label (New type)
Encoding: <type (1 octet), [op, bitmask]+>
Function: Contains a set of {operator, value} pairs that are
used to match the 20-bit Flow Label field [RFC2460]. The
operator byte is encoded as specified in the component type 3
of [RFC5575]. Values are encoded as 1-, 2-, or 4- byte
quantities.
The following example demonstrates the new prefix encoding for: "all
packets to ::1234:5678:9A00:0/64-104 from 192::/8 and port {range
[137, 139] or 8080}". In the destination prefix, "80-" represents
the prefix offset of 80 bits. In this exmaple, the 0 offset is
omitted from the printed source prefix.
+---------------------------+-------------+-------------------------+
| destination | source | port |
+---------------------------+-------------+-------------------------+
| 0x01 68 50 12 34 56 78 9A | 02 00 08 c0 | 04 03 89 45 8b 91 1f 90 |
+---------------------------+-------------+-------------------------+
3.1. Order of Traffic Filtering Rules
The orignal definition for the order of traffic filtering rules can
be reused with new consideration for the IPv6 prefix offset. As long
as the offsets are equal, the comparison is the same, retaining
longest-prefix-match semantics. If the offsets are not equal, the
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lowest offset has precedence, as this flow matches the most
significant bit.
Pseudocode:
flow_rule_v6_cmp (a, b)
{
comp1 = next_component(a);
comp2 = next_component(b);
while (comp1 || comp2) {
// component_type returns infinity on end-of-list
if (component_type(comp1) < component_type(comp2)) {
return A_HAS_PRECEDENCE;
}
if (component_type(comp1) > component_type(comp2)) {
return B_HAS_PRECEDENCE;
}
if (component_type(comp1) == IPV6_DESTINATION || IPV6_SOURCE) {
// offset not equal, lowest offset has precedence
// offset equal ...
common_len = MIN(prefix_length(comp1), prefix_length(comp2));
cmp = prefix_compare(comp1, comp2, offset, common_len);
// not equal, lowest value has precedence
// equal, longest match has precedence
} else {
common =
MIN(component_length(comp1), component_length(comp2));
cmp = memcmp(data(comp1), data(comp2), common);
// not equal, lowest value has precedence
// equal, longest string has precedence
}
}
return EQUAL;
}
4. IPv6 Flow Specification Traffic Filtering Action changes
One of the traffic filtering actions which can be expressed by BGP
extended community is defined in [RFC5575] as traffic-marking.
Another traffic filtering action defined in [RFC5575] as a BGP
extended community is redirect. To allow an IPv6 address specific
route-target, a new traffic action IPv6 address specific extended
community is provided.
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Therefore, for the purpose of making it compatible with IPv6 header
action expressed by presence of the extended community the following
text in [RFC5575] has been modified to read:
Traffic Marking (0x8009): The traffic marking extended community
instructs a system to modify first 6 bits of Traffic Class field
as (recommended by [RFC2474]) of a transiting IPv6 packet to the
corresponding value. This extended community is encoded as a
sequence of 42 zero bits followed by the 6 bits overwriting DSCP
portion of Traffic Class value.
Redirect-IPv6 (0x800B): redirect IPv6 address specific extended
community allows the traffic to be redirected to a VRF routing
instance that lists the specified IPv6 address specific route-
target in its import policy. If several local instances match
this criteria, the choice between them is a local matter (for
example, the instance with the lowest Route Distinguisher value
can be elected). This extended community uses the same encoding
as the IPv6 address specific Route Target extended community
[RFC5701].
5. Security Considerations
No new security issues are introduced to the BGP protocol by this
specification over the security concerins in [RFC5575]
6. IANA Considerations
This section complies with [RFC7153]
IANA is requested to rename currently defined SAFI 133 and SAFI 134
per [RFC5575] to read:
133 Dissemination of flow specification rules
134 L3VPN dissemination of flow specification rules
IANA is requested to create and maintain a new registry entitled:
"Flow Spec IPv6 Component Types". The initial values are:
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Type Description RFC
--------------------------------- ---------
Type 1 - Destination IPv6 Prefix [this draft]
Type 2 - Source IPv6 Prefix [this draft]
Type 3 - Next Header [this draft]
Type 4 - Port [this draft]
Type 5 - Destination port [this draft]
Type 6 - Source port [this draft]
Type 7 - ICMP type [this draft]
Type 8 - ICMP code [this draft]
Type 9 - TCP flags [this draft]
Type 10 - Packet length [this draft]
Type 11 - DSCP [this draft]
Type 12 - Fragment [this draft]
Type 13 - Flow Label [this draft]
7. Acknowledgements
Authors would like to thank Pedro Marques, Hannes Gredler and Bruno
Rijsman, Brian Carpenter, and Thomas Mangin for their valuable input.
8. References
8.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, DOI 10.17487/RFC2460,
December 1998, <http://www.rfc-editor.org/info/rfc2460>.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
DOI 10.17487/RFC2474, December 1998,
<http://www.rfc-editor.org/info/rfc2474>.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<http://www.rfc-editor.org/info/rfc4271>.
[RFC5492] Scudder, J. and R. Chandra, "Capabilities Advertisement
with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February
2009, <http://www.rfc-editor.org/info/rfc5492>.
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[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
<http://www.rfc-editor.org/info/rfc5575>.
[RFC5701] Rekhter, Y., "IPv6 Address Specific BGP Extended Community
Attribute", RFC 5701, DOI 10.17487/RFC5701, November 2009,
<http://www.rfc-editor.org/info/rfc5701>.
[RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme,
"IPv6 Flow Label Specification", RFC 6437,
DOI 10.17487/RFC6437, November 2011,
<http://www.rfc-editor.org/info/rfc6437>.
[RFC7153] Rosen, E. and Y. Rekhter, "IANA Registries for BGP
Extended Communities", RFC 7153, DOI 10.17487/RFC7153,
March 2014, <http://www.rfc-editor.org/info/rfc7153>.
8.2. Informative References
[RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation
of Type 0 Routing Headers in IPv6", RFC 5095,
DOI 10.17487/RFC5095, December 2007,
<http://www.rfc-editor.org/info/rfc5095>.
Authors' Addresses
Danny McPherson
Verisign, Inc.
Email: dmcpherson@verisign.com
Robert Raszuk (editor)
Bloomberg LP
731 Lexington Ave
New York City, NY 10022
USA
Email: robert@raszuk.net
Burjiz Pithawala
Individual
Email: burjizp@gmail.com
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Andy Karch
Cisco Systems
170 West Tasman Drive
San Jose, CA 95134
USA
Email: akarch@cisco.com
Susan Hares (editor)
Huawei
7453 Hickory Hill
Saline, MI 48176
USA
Email: shares@ndzh.com
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