IDR Working Group R. Raszuk, Ed.
Internet-Draft NTT MCL Inc.
Updates: RFC5575 (if approved) B. Pithawala
Intended status: Standards Track Cisco Systems
Expires: September 21, 2014 D. McPherson
Verisign, Inc.
A. Karch
Cisco Systems
March 20, 2014
Dissemination of Flow Specification Rules for IPv6
draft-ietf-idr-flow-spec-v6-05
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
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 21, 2014.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. IPv6 Flow Specification encoding in BGP . . . . . . . . . . . 2
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. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
8.1. Normative References . . . . . . . . . . . . . . . . . . 8
8.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
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.
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.
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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.
Type 1 - Destination IPv6 Prefix
Encoding: <type (1 octet), prefix offset (1 octet), prefix length
(1 octet), prefix>
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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 offset (1 octet), prefix length
(1 octet), prefix>
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]+>
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].
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]+>
Uses bitmask operand format defined above. Bit-7 is not used and
MUST be 0 to provide backwards-compatibility with the definition
in RFC5575.
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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, value]+>
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].
The following example demonstrates the new prefix encoding for: "all
packets to ::1234:5678:9A00:0/80-104 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 40 68 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
lowest offset has precedence, as this flow matches the most
significant bit.
Pseudocode:
flow_rule_v6_cmp (a, b)
{
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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. This
extended community type is of value: 0x8009.
For the purpose of making it compatible with IPv6 header action
expressed by presence of this extended community has been modified to
read:
Traffic Marking: 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.
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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. The extended community type has the value
0x800b.
Redirect-IPv6: The 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.
6. IANA Considerations
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 following component types have
been registered:
Type 1 - Destination IPv6 Prefix
Type 2 - Source IPv6 Prefix
Type 3 - Next Header
Type 4 - Port
Type 5 - Destination port
Type 6 - Source port
Type 7 - ICMP type
Type 8 - ICMP code
Type 9 - TCP flags
Type 10 - Packet length
Type 11 - DSCP
Type 12 - Fragment
Type 13 - Flow Label
7. Acknowledgments
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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
[I-D.ietf-6man-flow-3697bis]
Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme,
"IPv6 Flow Label Specification", draft-ietf-6man-flow-
3697bis-07 (work in progress), July 2011.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998.
[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, December
1998.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC5492] Scudder, J. and R. Chandra, "Capabilities Advertisement
with BGP-4", RFC 5492, February 2009.
[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, August 2009.
[RFC5701] Rekhter, Y., "IPv6 Address Specific BGP Extended Community
Attribute", RFC 5701, November 2009.
8.2. Informative References
[RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation
of Type 0 Routing Headers in IPv6", RFC 5095, December
2007.
Authors' Addresses
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Robert Raszuk (editor)
NTT MCL Inc.
101 S Ellsworth Avenue Suite 350
San Mateo, CA 94401
US
Email: robert@raszuk.net
Burjiz Pithawala
Cisco Systems
170 West Tasman Drive
San Jose, CA 95134
US
Email: bpithaw@cisco.com
Danny McPherson
Verisign, Inc.
Email: dmcpherson@verisign.com
Andy Karch
Cisco Systems
170 West Tasman Drive
San Jose, CA 95134
US
Email: akarch@cisco.com
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