Babel routing protocol B. Stark
Internet-Draft AT&T
Intended status: Informational M. Jethanandani
Expires: February 15, 2021 VMware
August 14, 2020
Babel Information Model
draft-ietf-babel-information-model-11
Abstract
This Babel Information Model provides structured data elements for a
Babel implementation reporting its current state and may allow
limited configuration of some such data elements. This information
model can be used as a basis for creating data models under various
data modeling regimes.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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Task Force (IETF). Note that other groups may also distribute
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This Internet-Draft will expire on February 15, 2021.
Copyright Notice
Copyright (c) 2020 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
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include Simplified BSD License text as described in Section 4.e 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
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Notation . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. The Information Model . . . . . . . . . . . . . . . . . . . . 7
3.1. Definition of babel-information-obj . . . . . . . . . . . 7
3.2. Definition of babel-constants-obj . . . . . . . . . . . . 9
3.3. Definition of babel-interface-obj . . . . . . . . . . . . 9
3.4. Definition of babel-if-stats-obj . . . . . . . . . . . . 12
3.5. Definition of babel-neighbor-obj . . . . . . . . . . . . 12
3.6. Definition of babel-route-obj . . . . . . . . . . . . . . 14
3.7. Definition of babel-mac-key-set-obj . . . . . . . . . . . 15
3.8. Definition of babel-mac-key-obj . . . . . . . . . . . . . 16
3.9. Definition of babel-dtls-cert-set-obj . . . . . . . . . . 17
3.10. Definition of babel-dtls-cert-obj . . . . . . . . . . . . 17
4. Extending the Information Model . . . . . . . . . . . . . . . 18
5. Security Considerations . . . . . . . . . . . . . . . . . . . 18
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 19
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
8.1. Normative References . . . . . . . . . . . . . . . . . . 19
8.2. Informative References . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
1. Introduction
Babel is a loop-avoiding distance-vector routing protocol defined in
[I-D.ietf-babel-rfc6126bis]. [I-D.ietf-babel-hmac] defines a
security mechanism that allows Babel packets to be cryptographically
authenticated, and [I-D.ietf-babel-dtls] defines a security mechanism
that allows Babel packets to be encrypted. This document describes
an information model for Babel (including implementations using one
or both of these security mechanisms) that can be used to create
management protocol data models (such as a NETCONF [RFC6241] YANG
[RFC7950] data model.
Due to the simplicity of the Babel protocol, most of the information
model is focused on reporting Babel protocol operational state, and
very little of that is considered mandatory to implement for an
implementation claiming compliance with this information model. Some
parameters may be configurable. However, it is up to the Babel
implementation whether to allow any of these to be configured within
its implementation. Where the implementation does not allow
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configuration of these parameters, it MAY still choose to expose them
as read-only.
The Information Model is presented using a hierarchical structure.
This does not preclude a data model based on this Information Model
from using a referential or other structure.
1.1. Requirements Language
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] and updated
by [RFC8174].
1.2. Notation
This document uses a programming language-like notation to define the
properties of the objects of the information model. An optional
property is enclosed by square brackets, [ ], and a list property is
indicated by two numbers in angle brackets, <m..n>, where m indicates
the minimal number of list elements, and n indicates the maximum
number of list elements. The symbol * for n means there are no
defined limits on the number of list elements. Each parameter and
object includes an indication of "ro" or "rw". "ro" means the
parameter or object is read-only. "rw" means it is read-write. For
an object, read-write means instances of the object can be created or
deleted. If an implementation is allowed to choose to implement a
"rw" parameter as read-only, this is noted in the parameter
description.
The object definitions use base types that are defined as follows:
binary A binary string (sequence of octets).
boolean A type representing a Boolean (true or false) value.
counter A non-negative integer that monotonically increases.
Counters may have discontinuities and they are not
expected to persist across restarts.
datetime A type representing a date and time using the Gregorian
calendar. The datetime format MUST conform to RFC 3339
[RFC3339].
ip-address A type representing an IP address. This type supports
both IPv4 and IPv6 addresses.
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operation A type representing a remote procedure call or other
action that can be used to manipulate data elements or
system behaviors.
reference A type representing a reference to another information or
data model element or to some other device resource.
string A type representing a human-readable string consisting of
a (possibly restricted) subset of Unicode and ISO/IEC
10646 [ISO.10646] characters.
uint A type representing an unsigned integer number. This
information model does not define a precision.
2. Overview
The Information Model is hierarchically structured as follows:
+-- babel-information
+-- babel-implementation-version
+-- babel-enable
+-- router-id
+-- self-seqno
+-- babel-metric-comp-algorithms
+-- babel-security-supported
+-- babel-mac-algorithms
+-- babel-dtls-cert-types
+-- babel-stats-enable
+-- babel-stats-reset
+-- babel-constants
| +-- babel-udp-port
| +-- babel-mcast-group
+-- babel-interfaces
| +-- babel-interface-reference
| +-- babel-interface-enable
| +-- babel-interface-metric-algorithm
| +-- babel-interface-split-horizon
| +-- babel-mcast-hello-seqno
| +-- babel-mcast-hello-interval
| +-- babel-update-interval
| +-- babel-mac-enable
| +-- babel-if-mac-key-sets
| +-- babel-mac-verify
| +-- babel-dtls-enable
| +-- babel-if-dtls-cert-sets
| +-- babel-dtls-cached-info
| +-- babel-dtls-cert-prefer
| +-- babel-packet-log-enable
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| +-- babel-packet-log
| +-- babel-if-stats
| | +-- babel-sent-mcast-hello
| | +-- babel-sent-mcast-update
| | +-- babel-sent-ucast-hello
| | +-- babel-sent-ucast-update
| | +-- babel-sent-IHU
| | +-- babel-received-packets
| +-- babel-neighbors
| +-- babel-neighbor-address
| +-- babel-hello-mcast-history
| +-- babel-hello-ucast-history
| +-- babel-txcost
| +-- babel-exp-mcast-hello-seqno
| +-- babel-exp-ucast-hello-seqno
| +-- babel-ucast-hello-seqno
| +-- babel-ucast-hello-interval
| +-- babel-rxcost
| +-- babel-cost
+-- babel-routes
| +-- babel-route-prefix
| +-- babel-route-prefix-length
| +-- babel-route-router-id
| +-- babel-route-neighbor
| +-- babel-route-received-metric
| +-- babel-route-calculated-metric
| +-- babel-route-seqno
| +-- babel-route-next-hop
| +-- babel-route-feasible
| +-- babel-route-selected
+-- babel-mac-key-sets
| +-- babel-mac-default-apply
| +-- babel-mac-keys
| +-- babel-mac-key-name
| +-- babel-mac-key-use-sign
| +-- babel-mac-key-use-verify
| +-- babel-mac-key-value
| +-- babel-mac-key-algorithm
| +-- babel-mac-key-test
+-- babel-dtls-cert-sets
+-- babel-dtls-default-apply
+-- babel-dtls-certs
+-- babel-cert-name
+-- babel-cert-value
+-- babel-cert-type
+-- babel-cert-private-key
+-- babel-cert-test
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Most parameters are read-only. Following is a descriptive list of
the parameters that are not required to be read-only:
o enable/disable Babel
o create/delete Babel MAC Key sets
o create/delete Babel DTLS Certificate sets
o enable/disable statistics collection
o Constant: UDP port
o Constant: IPv6 multicast group
o Interface: Metric algorithm
o Interface: Split horizon
o Interface: enable/disable Babel on this interface
o Interface: sets of MAC keys
o Interface: MAC algorithm
o Interface: verify received MAC packets
o Interface: set of DTLS certificates
o Interface: use cached info extensions
o Interface: preferred order of certificate types
o Interface: enable/disable packet log
o MAC-keys: create/delete entries
o MAC-keys: key used to sign packets
o MAC-keys: key used to verify packets
o DTLS-certs: create/delete entries
The following parameters are required to return no value when read:
o MAC key values
o DTLS certificate values
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Note that this overview is intended simply to be informative and is
not normative. If there is any discrepancy between this overview and
the detailed information model definitions in subsequent sections,
the error is in this overview.
3. The Information Model
3.1. Definition of babel-information-obj
object {
string ro babel-implementation-version;
boolean rw babel-enable;
binary ro babel-self-router-id;
[uint ro babel-self-seqno;]
string ro babel-metric-comp-algorithms<1..*>;
string ro babel-security-supported<0..*>;
[string ro babel-mac-algorithms<1..*>;]
[string ro babel-dtls-cert-types<1..*>;]
[boolean rw babel-stats-enable;]
[operation babel-stats-reset;]
babel-constants-obj ro babel-constants;
babel-interface-obj ro babel-interfaces<0..*>;
babel-route-obj ro babel-routes<0..*>;
[babel-mac-key-set-obj rw babel-mac-key-sets<0..*>;]
[babel-dtls-cert-set-obj rw babel-dtls-cert-sets<0..*>;]
} babel-information-obj;
babel-implementation-version: The name and version of this
implementation of the Babel protocol.
babel-enable: When written, it configures whether the protocol
should be enabled (true) or disabled (false). A read from the
running or intended datastore indicates the configured
administrative value of whether the protocol is enabled (true) or
not (false). A read from the operational datastore indicates
whether the protocol is actually running (true) or not (i.e., it
indicates the operational state of the protocol). A data model
that does not replicate parameters for running and operational
datastores can implement this as two separate parameters. An
implementation MAY choose to expose this parameter as read-only
("ro").
babel-self-router-id: The router-id used by this instance of the
Babel protocol to identify itself. [I-D.ietf-babel-rfc6126bis]
describes this as an arbitrary string of 8 octets. The router-id
value MUST NOT consist of all zeroes or all ones.
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babel-self-seqno: The current sequence number included in route
updates for routes originated by this node. This is a 16-bit
unsigned integer.
babel-metric-comp-algorithms: List of supported cost computation
algorithms. Possible values include "2-out-of-3", and "ETX". "2-
out-of-3" is described in [I-D.ietf-babel-rfc6126bis], section
A.2.1. "ETX" is described in [I-D.ietf-babel-rfc6126bis], section
A.2.2.
babel-security-supported: List of supported security mechanisms.
Possible values include "MAC" and "DTLS".
babel-mac-algorithms: List of supported MAC computation algorithms.
Possible values include "HMAC-SHA256", "BLAKE2s".
babel-dtls-cert-types: List of supported DTLS certificate types.
Possible values include "X.509" and "RawPublicKey".
babel-stats-enable: Indicates whether statistics collection is
enabled (true) or disabled (false) on all interfaces. When
enabled, existing statistics values are not cleared and will be
incremented as new packets are counted.
babel-stats-reset: An operation that resets all babel-if-stats
parameters to zero. This operation has no input or output
parameters.
babel-constants: A babel-constants-obj object.
babel-interfaces: A set of babel-interface-obj objects.
babel-routes: A set of babel-route-obj objects. Contains the routes
known to this node.
babel-mac-key-sets: A set of babel-mac-key-set-obj objects. If this
object is implemented, it provides access to parameters related to
the MAC security mechanism. An implementation MAY choose to
expose this object as read-only ("ro").
babel-dtls-cert-sets: A set of babel-dtls-cert-set-obj objects. If
this object is implemented, it provides access to parameters
related to the DTLS security mechanism. An implementation MAY
choose to expose this object as read-only ("ro").
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3.2. Definition of babel-constants-obj
object {
uint rw babel-udp-port;
[ip-address rw babel-mcast-group;]
} babel-constants-obj;
babel-udp-port: UDP port for sending and listening for Babel
packets. Default is 6696. An implementation MAY choose to expose
this parameter as read-only ("ro"). This is a 16-bit unsigned
integer.
babel-mcast-group: Multicast group for sending and listening to
multicast announcements on IPv6. Default is ff02::1:6. An
implementation MAY choose to expose this parameter as read-only
("ro").
3.3. Definition of babel-interface-obj
object {
reference ro babel-interface-reference;
[boolean rw babel-interface-enable;]
string rw babel-interface-metric-algorithm;
[boolean rw babel-interface-split-horizon;]
[uint ro babel-mcast-hello-seqno;]
[uint ro babel-mcast-hello-interval;]
[uint ro babel-update-interval;]
[boolean rw babel-mac-enable;]
[reference rw babel-if-mac-key-sets<0..*>;]
[boolean rw babel-mac-verify;]
[boolean rw babel-dtls-enable;]
[reference rw babel-if-dtls-cert-sets<0..*>;]
[boolean rw babel-dtls-cached-info;]
[string rw babel-dtls-cert-prefer<0..*>;]
[boolean rw babel-packet-log-enable;]
[reference ro babel-packet-log;]
[babel-if-stats-obj ro babel-if-stats;]
babel-neighbor-obj ro babel-neighbors<0..*>;
} babel-interface-obj;
babel-interface-reference: Reference to an interface object that can
be used to send and receive IPv6 packets, as defined by the data
model (e.g., YANG [RFC7950], BBF [TR-181]). Referencing syntax
will be specific to the data model. If there is no set of
interface objects available, this should be a string that
indicates the interface name used by the underlying operating
system.
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babel-interface-enable: When written, it configures whether the
protocol should be enabled (true) or disabled (false) on this
interface. A read from the running or intended datastore
indicates the configured administrative value of whether the
protocol is enabled (true) or not (false). A read from the
operational datastore indicates whether the protocol is actually
running (true) or not (i.e., it indicates the operational state of
the protocol). A data model that does not replicate parameters
for running and operational datastores can implement this as two
separate parameters. An implementation MAY choose to expose this
parameter as read-only ("ro").
babel-interface-metric-algorithm: Indicates the metric computation
algorithm used on this interface. The value MUST be one of those
listed in the babel-information-obj babel-metric-comp-algorithms
parameter. An implementation MAY choose to expose this parameter
as read-only ("ro").
babel-interface-split-horizon: Indicates whether or not the split
horizon optimization is used when calculating metrics on this
interface. A value of true indicates split horizon optimization
is used. Split horizon optimization is described in
[I-D.ietf-babel-rfc6126bis], section 3.7.4. An implementation MAY
choose to expose this parameter as read-only ("ro").
babel-mcast-hello-seqno: The current sequence number in use for
multicast Hellos sent on this interface. This is a 16-bit
unsigned integer.
babel-mcast-hello-interval: The current interval in use for
multicast Hellos sent on this interface. Units are centiseconds.
This is a 16-bit unsigned integer.
babel-update-interval: The current interval in use for all updates
(multicast and unicast) sent on this interface. Units are
centiseconds. This is a 16-bit unsigned integer.
babel-mac-enable: Indicates whether the MAC security mechanism is
enabled (true) or disabled (false). An implementation MAY choose
to expose this parameter as read-only ("ro").
babel-if-mac-keys-sets: List of references to the babel-mac entries
that apply to this interface. When an interface instance is
created, all babel-mac-key-sets instances with babel-mac-default-
apply "true" will be included in this list. An implementation MAY
choose to expose this parameter as read-only ("ro").
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babel-mac-verify A Boolean flag indicating whether MAC hashes in
incoming Babel packets are required to be present and are
verified. If this parameter is "true", incoming packets are
required to have a valid MAC hash. An implementation MAY choose
to expose this parameter as read-only ("ro").
babel-dtls-enable: Indicates whether the DTLS security mechanism is
enabled (true) or disabled (false). An implementation MAY choose
to expose this parameter as read-only ("ro").
babel-if-dtls-cert-sets: List of references to the babel-dtls-cert-
sets entries that apply to this interface. When an interface
instance is created, all babel-dtls-cert-sets instances with
babel-dtls-default-apply "true" will be included in this list. An
implementation MAY choose to expose this parameter as read-only
("ro").
babel-dtls-cached-info: Indicates whether the cached_info extension
is included in ClientHello and ServerHello packets. The extension
is included if the value is "true". An implementation MAY choose
to expose this parameter as read-only ("ro").
babel-dtls-cert-prefer: List of supported certificate types, in
order of preference. The values MUST be among those listed in the
babel-dtls-cert-types parameter. This list is used to populate
the server_certificate_type extension in a Client Hello. Values
that are present in at least one instance in the babel-dtls-certs
object of a referenced babel-dtls instance and that have a non-
empty babel-cert-private-key will be used to populate the
client_certificate_type extension in a Client Hello.
babel-packet-log-enable: Indicates whether packet logging is enabled
(true) or disabled (false) on this interface.
babel-packet-log: A reference or url link to a file that contains a
timestamped log of packets received and sent on babel-udp-port on
this interface. The [libpcap] file format with .pcap file
extension SHOULD be supported for packet log files. Logging is
enabled / disabled by babel-packet-log-enable. Implementations
will need to carefully manage and limit memory used by packet
logs.
babel-if-stats: Statistics collection object for this interface.
babel-neighbors: A set of babel-neighbor-obj objects.
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3.4. Definition of babel-if-stats-obj
object {
uint ro babel-sent-mcast-hello;
uint ro babel-sent-mcast-update;
uint ro babel-sent-ucast-hello;
uint ro babel-sent-ucast-update;
uint ro babel-sent-IHU;
uint ro babel-received-packets;
} babel-if-stats-obj;
babel-sent-mcast-hello: A count of the number of multicast Hello
packets sent on this interface.
babel-sent-mcast-update: A count of the number of multicast update
packets sent on this interface.
babel-sent-ucast-hello: A count of the number of unicast Hello
packets sent on this interface.
babel-sent-ucast-update: A count of the number of unicast update
packets sent on this interface.
babel-sent-IHU: A count of the number of IHU packets sent on this
interface.
babel-received-packets: A count of the number of Babel packets
received on this interface.
3.5. Definition of babel-neighbor-obj
object {
ip-address ro babel-neighbor-address;
[binary ro babel-hello-mcast-history;]
[binary ro babel-hello-ucast-history;]
uint ro babel-txcost;
uint ro babel-exp-mcast-hello-seqno;
uint ro babel-exp-ucast-hello-seqno;
[uint ro babel-ucast-hello-seqno;]
[uint ro babel-ucast-hello-interval;]
[uint ro babel-rxcost;]
[uint ro babel-cost;]
} babel-neighbor-obj;
babel-neighbor-address: IPv4 or IPv6 address the neighbor sends
packets from.
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babel-hello-mcast-history: The multicast Hello history of whether or
not the multicast Hello packets prior to babel-exp-mcast-hello-
seqno were received. A binary sequence where the most recently
received Hello is expressed as a "1" placed in the left-most bit,
with prior bits shifted right (and "0" bits placed between prior
Hello bits and most recent Hello for any not-received Hellos).
This value should be displayed using hex digits ([0-9a-fA-F]).
See [I-D.ietf-babel-rfc6126bis], section A.1.
babel-hello-ucast-history: The unicast Hello history of whether or
not the unicast Hello packets prior to babel-exp-ucast-hello-seqno
were received. A binary sequence where the most recently received
Hello is expressed as a "1" placed in the left-most bit, with
prior bits shifted right (and "0" bits placed between prior Hello
bits and most recent Hello for any not-received Hellos). This
value should be displayed using hex digits ([0-9a-fA-F]). See
[I-D.ietf-babel-rfc6126bis], section A.1.
babel-txcost: Transmission cost value from the last IHU packet
received from this neighbor, or maximum value to indicate the IHU
hold timer for this neighbor has expired. See
[I-D.ietf-babel-rfc6126bis], section 3.4.2. This is a 16-bit
unsigned integer.
babel-exp-mcast-hello-seqno: Expected multicast Hello sequence
number of next Hello to be received from this neighbor. If
multicast Hello packets are not expected, or processing of
multicast packets is not enabled, this MUST be NULL. This is a
16-bit unsigned integer; if the data model uses zero (0) to
represent NULL values for unsigned integers, the data model MAY
use a different data type that allows differentiation between zero
(0) and NULL.
babel-exp-ucast-hello-seqno: Expected unicast Hello sequence number
of next Hello to be received from this neighbor. If unicast Hello
packets are not expected, or processing of unicast packets is not
enabled, this MUST be NULL. This is a 16-bit unsigned integer; if
the data model uses zero (0) to represent NULL values for unsigned
integers, the data model MAY use a different data type that allows
differentiation between zero (0) and NULL.
babel-ucast-hello-seqno: The current sequence number in use for
unicast Hellos sent to this neighbor. If unicast Hellos are not
being sent, this MUST be NULL. This is a 16-bit unsigned integer;
if the data model uses zero (0) to represent NULL values for
unsigned integers, the data model MAY use a different data type
that allows differentiation between zero (0) and NULL.
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babel-ucast-hello-interval: The current interval in use for unicast
Hellos sent to this neighbor. Units are centiseconds. This is a
16-bit unsigned integer.
babel-rxcost: Reception cost calculated for this neighbor. This
value is usually derived from the Hello history, which may be
combined with other data, such as statistics maintained by the
link layer. The rxcost is sent to a neighbor in each IHU. See
[I-D.ietf-babel-rfc6126bis], section 3.4.3. This is a 16-bit
unsigned integer.
babel-cost: The link cost, as computed from the values maintained in
the neighbor table: the statistics kept in the neighbor table
about the reception of Hellos, and the txcost computed from
received IHU packets. This is a 16-bit unsigned integer.
3.6. Definition of babel-route-obj
object {
ip-address ro babel-route-prefix;
uint ro babel-route-prefix-length;
binary ro babel-route-router-id;
string ro babel-route-neighbor;
uint ro babel-route-received-metric;
uint ro babel-route-calculated-metric;
uint ro babel-route-seqno;
ip-address ro babel-route-next-hop;
boolean ro babel-route-feasible;
boolean ro babel-route-selected;
} babel-route-obj;
babel-route-prefix: Prefix (expressed in IP address format) for
which this route is advertised.
babel-route-prefix-length: Length of the prefix for which this route
is advertised.
babel-route-router-id: The router-id of the router that originated
this route.
babel-route-neighbor: Reference to the babel-neighbors entry for the
neighbor that advertised this route.
babel-route-received-metric: The metric with which this route was
advertised by the neighbor, or maximum value to indicate the route
was recently retracted and is temporarily unreachable (see
Section 3.5.5 of [I-D.ietf-babel-rfc6126bis]). This metric will
be NULL if the route was not received from a neighbor but was
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generated through other means. At least one of babel-route-
calculated-metric and babel-route-received-metric MUST be non-
NULL. Having both be non-NULL is expected for a route that is
received and subsequently advertised. This is a 16-bit unsigned
integer; if the data model uses zero (0) to represent NULL values
for unsigned integers, the data model MAY use a different data
type that allows differentiation between zero (0) and NULL.
babel-route-calculated-metric: A calculated metric for this route.
How the metric is calculated is implementation-specific. Maximum
value indicates the route was recently retracted and is
temporarily unreachable (see Section 3.5.5 of
[I-D.ietf-babel-rfc6126bis]). At least one of babel-route-
calculated-metric and babel-route-received-metric MUST be non-
NULL. Having both be non-NULL is expected for a route that is
received and subsequently advertised. This is a 16-bit unsigned
integer; if the data model uses zero (0) to represent NULL values
for unsigned integers, the data model MAY use a different data
type that allows differentiation between zero (0) and NULL.
babel-route-seqno: The sequence number with which this route was
advertised. This is a 16-bit unsigned integer.
babel-route-next-hop: The next-hop address of this route. This will
be empty if this route has no next-hop address.
babel-route-feasible: A Boolean flag indicating whether this route
is feasible, as defined in Section 3.5.1 of
[I-D.ietf-babel-rfc6126bis]).
babel-route-selected: A Boolean flag indicating whether this route
is selected (i.e., whether it is currently being used for
forwarding and is being advertised).
3.7. Definition of babel-mac-key-set-obj
object {
boolean rw babel-mac-default-apply;
babel-mac-key-obj rw babel-mac-keys<0..*>;
} babel-mac-obj;
babel-mac-default-apply: A Boolean flag indicating whether this
babel-mac instance is applied to all new babel-interface
instances, by default. If "true", this instance is applied to new
babel-interfaces instances at the time they are created, by
including it in the babel-interface-mac-keys list. If "false",
this instance is not applied to new babel-interfaces instances
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when they are created. An implementation MAY choose to expose
this parameter as read-only ("ro").
babel-mac-keys: A set of babel-mac-key-obj objects.
3.8. Definition of babel-mac-key-obj
object {
string rw babel-mac-key-name;
boolean rw babel-mac-key-use-sign;
boolean rw babel-mac-key-use-verify;
binary -- babel-mac-key-value;
string rw babel-mac-key-algorithm;
[operation babel-mac-key-test;]
} babel-mac-key-obj;
babel-mac-key-name: A unique name for this MAC key that can be used
to identify the key in this object instance, since the key value
is not allowed to be read. This value MUST NOT be empty and can
only be provided when this instance is created (i.e., it is not
subsequently writable). The value MAY be auto-generated if not
explicitly supplied when the instance is created.
babel-mac-key-use-sign: Indicates whether this key value is used to
sign sent Babel packets. Sent packets are signed using this key
if the value is "true". If the value is "false", this key is not
used to sign sent Babel packets. An implementation MAY choose to
expose this parameter as read-only ("ro").
babel-mac-key-use-verify: Indicates whether this key value is used
to verify incoming Babel packets. This key is used to verify
incoming packets if the value is "true". If the value is "false",
no MAC is computed from this key for comparing with the MAC in an
incoming packet. An implementation MAY choose to expose this
parameter as read-only ("ro").
babel-mac-key-value: The value of the MAC key. An implementation
MUST NOT allow this parameter to be read. This can be done by
always providing an empty string when read, or through
permissions, or other means. This value MUST be provided when
this instance is created, and is not subsequently writable. This
value is of a length suitable for the associated babel-mac-key-
algorithm. If the algorithm is based on the HMAC construction
[RFC2104], the length MUST be between 0 and the block size of the
underlying hash inclusive (where "HMAC-SHA256" block size is 64
bytes as described in [RFC4868]). If the algorithm is "BLAKE2s",
the length MUST be between 0 and 32 bytes inclusive, as described
in [RFC7693].
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babel-mac-key-algorithm The name of the MAC algorithm used with this
key. The value MUST be the same as one of the enumerations listed
in the babel-mac-algorithms parameter. An implementation MAY
choose to expose this parameter as read-only ("ro").
babel-mac-key-test: An operation that allows the MAC key and hash
algorithm to be tested to see if they produce an expected outcome.
Input to this operation is a binary string. The implementation is
expected to create a hash of this string using the babel-mac-key-
value and the babel-mac-key-algorithm. The output of this
operation is the resulting hash, as a binary string.
3.9. Definition of babel-dtls-cert-set-obj
object {
boolean rw babel-dtls-default-apply;
babel-dtls-cert-obj rw babel-dtls-certs<0..*>;
} babel-dtls-cert-set-obj;
babel-dtls-default-apply: A Boolean flag indicating whether this
babel-dtls instance is applied to all new babel-interface
instances, by default. If "true", this instance is applied to new
babel-interfaces instances at the time they are created, by
including it in the babel-interface-dtls-certs list. If "false",
this instance is not applied to new babel-interfaces instances
when they are created. An implementation MAY choose to expose
this parameter as read-only ("ro").
babel-dtls-certs: A set of babel-dtls-cert-obj objects. This
contains both certificates for this implementation to present for
authentication, and to accept from others. Certificates with a
non-empty babel-cert-private-key can be presented by this
implementation for authentication.
3.10. Definition of babel-dtls-cert-obj
object {
string rw babel-cert-name;
string rw babel-cert-value;
string rw babel-cert-type;
binary -- babel-cert-private-key;
[operation babel-cert-test;]
} babel-dtls-cert-obj;
babel-cert-name: A unique name for this DTLS certificate that can be
used to identify the certificate in this object instance, since
the value is too long to be useful for identification. This value
MUST NOT be empty and can only be provided when this instance is
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created (i.e., it is not subsequently writable). The value MAY be
auto-generated if not explicitly supplied when the instance is
created.
babel-cert-value: The DTLS certificate in PEM format [RFC7468].
This value MUST be provided when this instance is created, and is
not subsequently writable.
babel-cert-type: The name of the certificate type of this object
instance. The value MUST be the same as one of the enumerations
listed in the babel-dtls-cert-types parameter. This value can
only be provided when this instance is created, and is not
subsequently writable.
babel-cert-private-key: The value of the private key. If this is
non-empty, this certificate can be used by this implementation to
provide a certificate during DTLS handshaking. An implementation
MUST NOT allow this parameter to be read. This can be done by
always providing an empty string when read, or through
permissions, or other means. This value can only be provided when
this instance is created, and is not subsequently writable.
babel-cert-test: An operation that allows a hash of the provided
input string to be created using the certificate public key and
the SHA-256 hash algorithm. Input to this operation is a binary
string. The output of this operation is the resulting hash, as a
binary string.
4. Extending the Information Model
Implementations MAY extend this information model with other
parameters or objects. For example, an implementation MAY choose to
expose Babel route filtering rules by adding a route filtering object
with parameters appropriate to how route filtering is done in that
implementation. The precise means used to extend the information
model would be specific to the data model the implementation uses to
expose this information.
5. Security Considerations
This document defines a set of information model objects and
parameters that may be exposed to be visible from other devices, and
some of which may be configured. Securing access to and ensuring the
integrity of this data is in scope of and the responsibility of any
data model derived from this information model. Specifically, any
YANG [RFC7950] data model is expected to define security exposure of
the various parameters, and a [TR-181] data model will be secured by
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the mechanisms defined for the management protocol used to transport
it.
Misconfiguration (whether unintentional or malicious) can prevent
reachability or cause poor network performance (increased latency,
jitter, etc.). The information in this model discloses network
topology, which can be used to mount subsequent attacks on traffic
traversing the network.
This information model defines objects that can allow credentials
(for this device, for trusted devices, and for trusted certificate
authorities) to be added and deleted. Public keys may be exposed
through this model. This model requires that private keys never be
exposed. The Babel security mechanisms that make use of these
credentials (e.g., [I-D.ietf-babel-dtls], [I-D.ietf-babel-hmac])
identify what credentials can be used with those mechanisms.
MAC keys are allowed to be as short as zero-length. This is useful
for testing. Network operators are advised to follow current best
practices for key length and generation of keys related to the MAC
algorithm associated with the key. Short (and zero-length) keys and
keys that make use of only alphanumeric characters are highly
susceptible to brute force attacks.
6. IANA Considerations
This document has no IANA actions.
7. Acknowledgements
Juliusz Chroboczek, Toke Hoeiland-Joergensen, David Schinazi, Antonin
Decimo, Acee Lindem, and Carsten Bormann have been very helpful in
refining this information model.
The language in the Notation section was mostly taken from [RFC8193].
8. References
8.1. Normative References
[I-D.ietf-babel-rfc6126bis]
Chroboczek, J. and D. Schinazi, "The Babel Routing
Protocol", draft-ietf-babel-rfc6126bis-19 (work in
progress), August 2020.
[libpcap] Wireshark, "Libpcap File Format", 2015,
<https://wiki.wireshark.org/Development/
LibpcapFileFormat>.
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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/info/rfc2119>.
[RFC7468] Josefsson, S. and S. Leonard, "Textual Encodings of PKIX,
PKCS, and CMS Structures", RFC 7468, DOI 10.17487/RFC7468,
April 2015, <https://www.rfc-editor.org/info/rfc7468>.
[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/info/rfc8174>.
8.2. Informative References
[I-D.ietf-babel-dtls]
Decimo, A., Schinazi, D., and J. Chroboczek, "Babel
Routing Protocol over Datagram Transport Layer Security",
draft-ietf-babel-dtls-10 (work in progress), June 2020.
[I-D.ietf-babel-hmac]
Do, C., Kolodziejak, W., and J. Chroboczek, "MAC
authentication for the Babel routing protocol", draft-
ietf-babel-hmac-10 (work in progress), August 2019.
[ISO.10646]
International Organization for Standardization,
"Information Technology - Universal Multiple-Octet Coded
Character Set (UCS)", ISO Standard 10646:2014, 2014.
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104,
DOI 10.17487/RFC2104, February 1997,
<https://www.rfc-editor.org/info/rfc2104>.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>.
[RFC4868] Kelly, S. and S. Frankel, "Using HMAC-SHA-256, HMAC-SHA-
384, and HMAC-SHA-512 with IPsec", RFC 4868,
DOI 10.17487/RFC4868, May 2007,
<https://www.rfc-editor.org/info/rfc4868>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
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[RFC7693] Saarinen, M-J., Ed. and J-P. Aumasson, "The BLAKE2
Cryptographic Hash and Message Authentication Code (MAC)",
RFC 7693, DOI 10.17487/RFC7693, November 2015,
<https://www.rfc-editor.org/info/rfc7693>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8193] Burbridge, T., Eardley, P., Bagnulo, M., and J.
Schoenwaelder, "Information Model for Large-Scale
Measurement Platforms (LMAPs)", RFC 8193,
DOI 10.17487/RFC8193, August 2017,
<https://www.rfc-editor.org/info/rfc8193>.
[TR-181] Broadband Forum, "Device Data Model",
<http://cwmp-data-models.broadband-forum.org/>.
Authors' Addresses
Barbara Stark
AT&T
Atlanta, GA
US
Email: barbara.stark@att.com
Mahesh Jethanandani
VMware
California
US
Email: mjethanandani@gmail.com
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