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Babel routing protocol                                          B. Stark
Internet-Draft                                                      AT&T
Intended status: Informational                           M. Jethanandani
Expires: April 11, 2020                                           VMware
                                                         October 9, 2019


                        Babel Information Model
                 draft-ietf-babel-information-model-10

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

   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 April 11, 2020.

Copyright Notice

   Copyright (c) 2019 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 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 . . . . . . . . . . . .   8
     3.3.  Definition of babel-interfaces-obj  . . . . . . . . . . .   9
     3.4.  Definition of babel-if-stats-obj  . . . . . . . . . . . .  11
     3.5.  Definition of babel-neighbors-obj . . . . . . . . . . . .  12
     3.6.  Definition of babel-routes-obj  . . . . . . . . . . . . .  14
     3.7.  Definition of babel-mac-key-sets-obj  . . . . . . . . . .  15
     3.8.  Definition of babel-mac-keys-obj  . . . . . . . . . . . .  16
     3.9.  Definition of babel-dtls-cert-sets-obj  . . . . . . . . .  17
     3.10. Definition of babel-dtls-certs-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-interfaces-obj     ro babel-interfaces<0..*>;
         babel-routes-obj         ro babel-routes<0..*>;
        [babel-mac-key-sets-obj   rw babel-mac-key-sets<0..*>;]
        [babel-dtls-cert-sets-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.

   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 babel-mac-key-sets-obj object.  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 babel-dtls-cert-sets-obj object.  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").

3.2.  Definition of babel-constants-obj







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     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-interfaces-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-neighbors-obj  ro babel-neighbors<0..*>;
      } babel-interfaces-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.

   babel-interface-enable:  When written, it configures whether the
      protocol should be enabled (true) or disabled (false) on this



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      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").

   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



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      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.

   babel-if-stats:  Statistics collection object for this interface.

   babel-neighbors:  A set of babel-neighbors-obj objects.

3.4.  Definition of babel-if-stats-obj









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     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-neighbors-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-neighbors-obj;

   babel-neighbor-address:  IPv4 or IPv6 address the neighbor sends
      packets from.

   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



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      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.

   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.



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   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-routes-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-routes-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
      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



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      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-sets-obj

     object {
          boolean               rw babel-mac-default-apply;
          babel-mac-keys-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
      when they are created.  An implementation MAY choose to expose
      this parameter as read-only ("ro").

   babel-mac-keys:  A set of babel-mac-keys-obj objects.




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3.8.  Definition of babel-mac-keys-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-keys-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-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-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-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].

   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").




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   babel-mac-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-algorithm.  The output of this operation
      is the resulting hash, as a binary string.

3.9.  Definition of babel-dtls-cert-sets-obj

     object {
          boolean               rw babel-dtls-default-apply;
          babel-dtls-certs-obj  rw babel-dtls-certs<0..*>;
      } babel-dtls-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-keys-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-certs-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-certs-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
      created (i.e., it is not subsequently writable).  The value MAY be
      auto-generated if not explicitly supplied when the instance is
      created.





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   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
   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,



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   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, 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-14 (work in
              progress), August 2019.

   [libpcap]  Wireshark, "Libpcap File Format", 2015,
              <https://wiki.wireshark.org/Development/
              LibpcapFileFormat>.

   [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>.



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   [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-09 (work in progress), August 2019.

   [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>.

   [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>.



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   [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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