Internet DRAFT - draft-trammell-ipfix-text-adt
draft-trammell-ipfix-text-adt
IPFIX Working Group B. Trammell
Internet-Draft ETH Zurich
Intended status: Informational November 08, 2013
Expires: May 12, 2014
Textual Representation of IPFIX Abstract Data Types
draft-trammell-ipfix-text-adt-03.txt
Abstract
This document defines UTF-8 representations for IPFIX abstract data
types, to support interoperable usage of the IPFIX Information
Elements with protocols based on textual encodings.
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 May 12, 2014.
Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Identifying Information Elements . . . . . . . . . . . . . . 3
4. Data Type Encodings . . . . . . . . . . . . . . . . . . . . . 3
4.1. octetArray . . . . . . . . . . . . . . . . . . . . . . . 3
4.2. unsigned8, unsigned16, unsigned32, and unsigned64 . . . . 4
4.3. signed8, signed16, signed32, and signed64 . . . . . . . . 5
4.4. float32 and float64 . . . . . . . . . . . . . . . . . . . 5
4.5. boolean . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.6. macAddress . . . . . . . . . . . . . . . . . . . . . . . 6
4.7. string . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.8. dateTime* . . . . . . . . . . . . . . . . . . . . . . . . 7
4.9. ipv4Address . . . . . . . . . . . . . . . . . . . . . . . 7
4.10. ipv6Address . . . . . . . . . . . . . . . . . . . . . . . 8
4.11. basicList, subTemplateList, and subTemplateMultiList . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 8
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.1. Normative References . . . . . . . . . . . . . . . . . . 9
7.2. Informative References . . . . . . . . . . . . . . . . . 9
Appendix A. Example . . . . . . . . . . . . . . . . . . . . . . 9
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
The IPFIX Information Model, as defined by the IANA IPFIX Information
Element Registry, provides a rich set of Information Elements for
description of information about network entities and network traffic
data, and abstract data types for these Information Elements. The
IPFIX Protocol Specification [RFC7011], in turn, defines a big-endian
binary encoding for these abstract data types suitable for use with
the IPFIX Protocol.
However, present and future operations and management protocols and
applications may use textual encodings, and generic framing and
structure as in JSON or XML. A definition of canonical textual
encodings for the IPFIX abstract data types would allow this set of
Information Elements to be used for such applications, and for these
applications to interoperate with IPFIX applications at the
Information Element definition level.
Note that templating or other mechanisms for data description for
such applications and protocols are application specific, and
therefore out of scope for this document: only Information Element
identification and data value representation are defined here.
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2. Terminology
Capitalized terms defined in the IPFIX Protocol Specification
[RFC7011] and the IPFIX Information Model [RFC7012] are used in this
document as defined in those documents. In addition, this document
defines the following terminology for its own use:
Enclosing Context
Textual representation of IPFIX data values is applied to use the
IPFIX Information Model within some existing textual format (e.g.
XML, JSON). This outer format is referred to as the Enclosing
Context within this document. Enclosing Contexts define escaping
and quoting rules for represented data values.
3. Identifying Information Elements
The IPFIX Information Element Registry [iana-ipfix-assignments]
defines a set of Information Elements and numbered by Information
Element Identifiers, and named for human-readability. These
Information Element Identifiers are meant for use with the IPFIX
protocol, and have little meaning when applying the IPFIX Information
Element Registry to textual representations.
Instead, applications using textual representations of Information
Elements SHOULD use Information Element names to identify them; see
Appendix A for examples illustrating this principle.
4. Data Type Encodings
Each subsection of this section defines a textual encoding for the
abstract data types defined in [RFC7012]. This section uses ABNF
[RFC5234], including the Core Rules in Appendix B, to describe the
format of textual representations of IPFIX abstract data types.
4.1. octetArray
If the Enclosing Context defines a representation for binary objects,
that representation SHOULD be used.
Otherwise, since the goal of textual representation of Information
Elements is readability over compactness, the values of Information
Elements of the octetArray data type are represented as a string of
pairs of hexadecimal digits, one pair per byte, in the order the
bytes would appear on the wire were the octetArray encoded directly
in IPFIX per [RFC7011]. Whitespace may occur between any pair of
digits to assist in human readability of the string, but is not
necessary, and must be disregarded by any process reading the string.
In ABNF:
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hex-octet = 2HEXDIGIT
octetarray = 1* (hex-octet [WSP])
4.2. unsigned8, unsigned16, unsigned32, and unsigned64
If the Enclosing Context defines a representation for unsigned
integers, that representation SHOULD be used.
In the special case that the unsigned Information Element has
identifier semantics, and refers to a set of codepoints, either in an
external registry, a sub-registry, or directly in the description of
the Information Element, then the name or short description for that
codepoint MAY be used to improve readability.
Otherwise, the values of Information Elements of an unsigned integer
type may be represented either as unprefixed base-10 (decimal)
strings, or as base-16 (hexadecimal) strings prefixed by '0x'; in
ABNF:
unsigned = 1*DIGIT / '0x' 1*HEXDIG
Leading zeroes are allowed in either encoding, and do not signify
base-8 (octal) encoding.
The encoded value must be in range for the corresponding abstract
data type or Information Element. Out of range values should be
interpreted as clipped to the implicit range for the Information
Element as defined by the abstract data type, or to the explicit
range of the Information Element if defined. Minimum and maximum
values for abstract data types are shown in Table 1 below.
+------------+---------+----------------------+
| type | minimum | maximum |
+------------+---------+----------------------+
| unsigned8 | 0 | 255 |
| unsigned16 | 0 | 65536 |
| unsigned32 | 0 | 4294967295 |
| unsigned64 | 0 | 18446744073709551615 |
+------------+---------+----------------------+
Table 1: Ranges for unsigned abstract data types
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4.3. signed8, signed16, signed32, and signed64
If the Enclosing Context defines a representation for signed
integers, that representation SHOULD be used.
Otherwise, the values of Information Elements of signed integer types
should be represented as optionally-prefixed base-10 (decimal)
strings. In ABNF:
sign = "+" / "-"
signed = [sign] 1*DIGIT
If the sign is omitted, it is assumed to be positive. Leading zeroes
are allowed, and do not signify base-8 (octal) encoding.
The encoded value must be in range for the corresponding abstract
data type or Information Element. Out of range values should be
interpreted as clipped to the implicit range for the Information
Element as defined by the abstract data type, or to the explicit
range of the Information Element if defined. Minimum and maximum
values for abstract data types are shown in Table 2 below.
+----------+----------------------+----------------------+
| type | minimum | maximum |
+----------+----------------------+----------------------+
| signed8 | -128 | +127 |
| signed16 | -32768 | +32767 |
| signed32 | -2147483648 | +2147483647 |
| signed64 | -9223372036854775808 | +9223372036854775807 |
+----------+----------------------+----------------------+
Table 2: Ranges for signed abstract data types
4.4. float32 and float64
If the Enclosing Context defines a representation for floating point
numbers, that representation SHOULD be used.
Otherwise, the values of Information Elements of float32 or float64
types are represented as an optionally sign-prefixed, optionally
base-10 exponent-suffixed, floating point decimal number. In ABNF:
sign = "+" / "-"
exponent = 'e' 1*3DIGIT
right-decimal = '.' 0*DIGIT
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mantissa = 1*DIGIT [right-decimal]
float = [sign] mantissa [exponent]
The expressed value is ( mantissa * 10 ^ exponent ). If the sign is
omitted, it is assumed to be positive. If the exponent is omitted,
it is assumed to be zero. Leading zeroes may appear in the mantissa
and/or the exponent.
Minimum and maximum values for abstract data types are shown in Table
3below.
+---------+----------------+----------------+
| type | minimum abs(x) | maximum abs(x) |
+---------+----------------+----------------+
| float32 | 5.877e-39 | 3.403e38 |
| float64 | 1.1125e-308 | +1.798e308 |
+---------+----------------+----------------+
Table 3: Ranges for floating-point abstract data types
4.5. boolean
If the Enclosing Context defines a representation for boolean values,
that representation SHOULD be used.
Otherwise, a true boolean value should be represented with the
literal string 1, and a false boolean value with the literal string
0. In ABNF:
boolean-yes = "1"
boolean-no = "0"
boolean = boolean-yes / boolean-no
4.6. macAddress
MAC addresses are represented as IEEE 802 MAC-48 addresses,
hexadecimal bytes, most significant byte first, separated by colons.
In ABNF, using the hex-octet production from Section 4.1:
macaddress = hex-octet 5( ":" hex-octet )
4.7. string
As Information Elements of the string type are simply UTF-8 encoded
strings, they are represented directly, subject to the escaping and
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encoding rules of the Enclosing Context. If the Enclosing Context
cannot natively represent UTF-8 characters, the escaping facility
provided by the Enclosing Context must be used for non-representable
characters. Additionally, strings containing characters reserved in
the Enclosing Context (e.g. markup characters, quotes) must be
escaped or quoted according to the rules of the Enclosing Context.
4.8. dateTime*
Timestamp abstract data types are represented generally as in
[RFC3339], with two important differences. First, all IPFIX
timestamps are expressed in terms of UTC, so textual representations
of these Information Elements are explictly in UTC as well. Time
zone offsets are therefore not required or supported. Second, there
are four timestamp abstract data types, separated by the precision
which they can express. Fractional seconds must be omitted in
dateTimeSeconds, expressed in milliseconds in dateTimeMilliseconds,
and so on.
In ABNF, taken from [RFC3339] and modified:
date-fullyear = 4DIGIT
date-month = 2DIGIT ; 01-12
date-mday = 2DIGIT ; 01-28, 01-29, 01-30, 01-31
time-hour = 2DIGIT ; 00-23
time-minute = 2DIGIT ; 00-59
time-second = 2DIGIT ; 00-58, 00-59, 00-60
time-msec = "." 3*DIGIT
time-usec = "." 6*DIGIT
time-nsec = "." 9*DIGIT
partial-time = time-hour ":" time-minute ":" time-second
datetimeseconds = full-date "T" partial-time
datetimemilliseconds = full-date "T" partial-time "." time-msec
datetimemicroseconds = full-date "T" partial-time "." time-usec
datetimenanoseconds = full-date "T" partial-time "." time-nsec
4.9. ipv4Address
IP version 4 addresses are represented in dotted-quad format, most-
significant-byte first, as it would in a Uniform Resource Identifier
[RFC3986]; the ABNF for an IPv4 address is taken from [RFC3986] and
reproduced below:
dec-octet = DIGIT ; 0-9
/ %x31-39 DIGIT ; 10-99
/ "1" 2DIGIT ; 100-199
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/ "2" %x30-34 DIGIT ; 200-249
/ "25" %x30-35 ; 250-255
ipv4address = dec-octet 3("." dec-octet)
4.10. ipv6Address
IP version 6 addresses are represented as in section 2.2 of
[RFC4291], as updated by section 4 of [RFC5952]. The ABNF for an
IPv6 address is taken from [RFC3986] and reproduced below:
ls32 = ( h16 ":" h16 ) / IPv4address
; least-significant 32 bits of address
h16 = 1*4HEXDIG
; 16 bits of address represented in hexadecimal
; zeroes to suppressed as in RFC 5952
ipv6address = 6( h16 ":" ) ls32
/ "::" 5( h16 ":" ) ls32
/ [ h16 ] "::" 4( h16 ":" ) ls32
/ [ *1( h16 ":" ) h16 ] "::" 3( h16 ":" ) ls32
/ [ *2( h16 ":" ) h16 ] "::" 2( h16 ":" ) ls32
/ [ *3( h16 ":" ) h16 ] "::" h16 ":" ls32
/ [ *4( h16 ":" ) h16 ] "::" ls32
/ [ *5( h16 ":" ) h16 ] "::" h16
/ [ *6( h16 ":" ) h16 ] "::"
4.11. basicList, subTemplateList, and subTemplateMultiList
These abstract data types, defined for IPFIX Structured Data
[RFC6313], do not represent actual data types; they are instead
designed to provide a mechanism by which complex structure can be
represented in IPFIX below the template level. It is assumed that
protocols using textual Information Element representation will
provide their own structure. Therefore, Information Elements of
these Data Types MUST NOT be used in textual representations.
5. Security Considerations
This document does not present any additional security measures
beyond those presented by [RFC7011].
6. IANA Considerations
This document has no considerations for IANA.
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7. References
7.1. Normative References
[RFC3339] Klyne, G., Ed. and C. Newman, "Date and Time on the
Internet: Timestamps", RFC 3339, July 2002.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, RFC
3986, January 2005.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008.
[RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
Address Text Representation", RFC 5952, August 2010.
[RFC7011] Claise, B., Trammell, B., and P. Aitken, "Specification of
the IP Flow Information Export (IPFIX) Protocol for the
Exchange of Flow Information", STD 77, RFC 7011, September
2013.
[iana-ipfix-assignments]
Internet Assigned Numbers Authority, ., "IP Flow
Information Export Information Elements
(http://www.iana.org/assignments/ipfix/ipfix.xml)",
November 2012.
7.2. Informative References
[RFC6313] Claise, B., Dhandapani, G., Aitken, P., and S. Yates,
"Export of Structured Data in IP Flow Information Export
(IPFIX)", RFC 6313, July 2011.
[RFC7012] Claise, B. and B. Trammell, "Information Model for IP Flow
Information Export (IPFIX)", RFC 7012, September 2013.
[RFC7013] Trammell, B. and B. Claise, "Guidelines for Authors and
Reviewers of IP Flow Information Export (IPFIX)
Information Elements", BCP 184, RFC 7013, September 2013.
Appendix A. Example
In this section, we examine an IPFIX Template and a Data Record
defined by that Template, and show how that Data Record would be
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represented in JSON according to the specification in this document.
Note that this is specifically NOT a recommendation for a particular
representation, merely an illustration of the encodings in this
document.
Figure 1 shows a Template in IEspec format as defined in section 9.1
of [RFC7013]. A Message containing this Template and a Data Record
is shown in Figure 2, and a corresponding JSON Object using the text
format defined in this document is shown in Figure 3.
flowStartMilliseconds(152)<dateTimeMilliseconds>[8]
flowEndMilliseconds(153)<dateTimeMilliseconds>[8]
octetDeltaCount(1)<unsigned64>[4]
packetDeltaCount(2)<unsigned64>[4]
sourceIPv6Address(27)<ipv4Address>[4]{key}
destinationIPv6Address(28)<ipv4Address>[4]{key}
sourceTransportPort(7)<unsigned16>[2]{key}
destinationTransportPort(11)<unsigned16>[2]{key}
protocolIdentifier(4)<unsigned8>[1]{key}
tcpControlBits(6)<unsigned8>[1]
flowEndReason(136)<unsigned8>[1]
Figure 1: Sample flow template (IPFIX)
1 2 3 4 5 6
0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x000a | length 135 | export time 1352140263 | msg
| sequence 0 | domain 1 | hdr
| SetID 2 | length 52 | tid 256 | fields 11 | tmpl
| IE 152 | length 8 | IE 153 | length 8 | set
| IE 1 | length 4 | IE 2 | length 4 |
| IE 27 | length 16 | IE 28 | length 16 |
| IE 7 | length 2 | IE 11 | length 2 |
| IE 4 | length 1 | IE 6 | length 1 |
| IE 136 | length 1 | SetID 256 | length 83 | data
| start time 1352140261135 | set
| end time 1352140262880 |
| octets 195383 | packets 88 |
| sip6 |
| 2001:0db8:000c:1337:0000:0000:0000:0002 |
| dip6 |
| 2001:0db8:000c:1337:0000:0000:0000:0003 |
| sp 80 | dp 32991 | prt 6 | tcp 19| fe 3 |
+-------------------------------------------------------+
Figure 2: IPFIX message containing sample flow
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{
"flowStartMilliseconds": "2012-11-05T18:31:01.135",
"flowEndMilliseconds": "2012-11-05T18:31:02.880",
"octetDeltaCount": 195383,
"packetDeltaCount": 88,
"sourceIPv6Address": "2001:db8:c:1337::2",
"destinationIPv6Address": "2001:db8:c:1337::3",
"sourceTransportPort": 80,
"destinationTransportPort": 32991,
"protocolIdentifier": "tcp",
"tcpControlBits": 19,
"flowEndReason": 3
}
Figure 3: JSON object containing sample flow
Author's Address
Brian Trammell
Swiss Federal Institute of Technology Zurich
Gloriastrasse 35
8092 Zurich
Switzerland
Phone: +41 44 632 70 13
Email: trammell@tik.ee.ethz.ch
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