Network Configuration Protocol (NETCONF) Base Notifications
draft-ietf-netconf-system-notifications-07

NETCONF                                                       A. Bierman
Internet-Draft                                                   Brocade
Intended status: Standards Track                        December 9, 2011
Expires: June 11, 2012

      Network Configuration Protocol (NETCONF) Base Notifications
               draft-ietf-netconf-system-notifications-07

Abstract

   The NETCONF protocol provides mechanisms to manipulate configuration
   datastores.  However, client applications often need to be aware of
   common events such as a change in NETCONF server capabilities, that
   may impact management applications.  Standard mechanisms are needed
   to support the monitoring of the base system events within the
   NETCONF server.  This document defines a YANG module that allows a
   NETCONF client to receive notifications for some common system
   events.

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 http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on June 11, 2012.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   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

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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
   2.  YANG Module for NETCONF Base Notifications . . . . . . . . . .  3
     2.1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . .  3
     2.2.  Definitions  . . . . . . . . . . . . . . . . . . . . . . .  4
   3.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 12
   4.  Security Considerations  . . . . . . . . . . . . . . . . . . . 12
   5.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 14
   6.  Normative References . . . . . . . . . . . . . . . . . . . . . 14
   Appendix A.  Change Log  . . . . . . . . . . . . . . . . . . . . . 15
     A.1.  06-07  . . . . . . . . . . . . . . . . . . . . . . . . . . 15
     A.2.  05-06  . . . . . . . . . . . . . . . . . . . . . . . . . . 15
     A.3.  04-05  . . . . . . . . . . . . . . . . . . . . . . . . . . 15
     A.4.  03-04  . . . . . . . . . . . . . . . . . . . . . . . . . . 16
     A.5.  02-03  . . . . . . . . . . . . . . . . . . . . . . . . . . 16
     A.6.  01-02  . . . . . . . . . . . . . . . . . . . . . . . . . . 16
     A.7.  00-01  . . . . . . . . . . . . . . . . . . . . . . . . . . 17
     A.8.  00 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
   Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 17

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1.  Introduction

   The NETCONF protocol [RFC6241] provides mechanisms to manipulate
   configuration datastores.  However, client applications often need to
   be aware of common events such as a change in NETCONF server
   capabilities, that may impact management applications.  Standard
   mechanisms are needed to support the monitoring of the base system
   events within the NETCONF server.  This document defines a YANG
   module [RFC6020] that allows a NETCONF client to receive
   notifications for some common system events.

1.1.  Terminology

   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].

   The following terms are defined in [RFC6241]:
   o  client
   o  datastore
   o  protocol operation
   o  server

   The following terms are defined in [RFC5277]:
   o  event
   o  stream
   o  subscription

   The following term is defined in [RFC6020]:
   o  data node

2.  YANG Module for NETCONF Base Notifications

2.1.  Overview

   The YANG module defined within this document specifies a small number
   of event notification messages for use within the 'NETCONF' stream,
   and accessible to clients via the subscription mechanism in
   [RFC5277].  This module imports data types from the 'ietf-netconf'
   module defined in [RFC6241] and 'ietf-inet-types' module defined in
   [RFC6021].

   These notifications pertain to configuration and monitoring portion
   of the managed system, not the entire system.  A server MUST report
   events that are directly related to the NETCONF protocol.  A server
   MAY report events for non-NETCONF management sessions, using the
   'session-id' value of zero.

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   This module defines the following notifications for the 'NETCONF'
   stream to notify a client application that the NETCONF server state
   has changed:

   netconf-config-change:
      Generated when the NETCONF server detects that the <running> or
      <startup> configuration datastore has changed.  Summarizes the
      edits that have been detected.
   netconf-capability-change:
      Generated when the NETCONF server detects that the server
      capabilities have changed.  Indicates which capabilities have been
      added, deleted, and/or modified.  The manner in which a server
      capability is changed is outside the scope of this document.
   netconf-session-start:
      Generated when a NETCONF server detects that a NETCONF session has
      started.  A server MAY generate this event for non-NETCONF
      management sessions.  For example, a CLI-based session could be
      detected and monitored by the server.  Indicates the identity of
      the user that started the session.
   netconf-session-end:
      Generated when a NETCONF server detects that a NETCONF session has
      terminated.  A server MAY optionally generate this event for non-
      NETCONF management sessions.  For example, a CLI-based session
      could be detected and monitored by the server.  Indicates the
      identity of the user that owned the session, and why the session
      was terminated.
   netconf-confirmed-commit:
      Generated when a NETCONF server detects that a confirmed-commit
      event has occurred.  Indicates the event and the current state of
      the confirmed-commit procedure in progress.

2.2.  Definitions

 <CODE BEGINS> file="ietf-netconf-notifications@2011-12-09.yang"

 module ietf-netconf-notifications {

    namespace
      "urn:ietf:params:xml:ns:yang:ietf-netconf-notifications";

    prefix ncn;

    import ietf-inet-types { prefix inet; }
    import ietf-netconf { prefix nc; }

    organization

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     "IETF NETCONF (Network Configuration Protocol) Working Group";

    contact
     "WG Web:   <http://tools.ietf.org/wg/netconf/>
      WG List:  <mailto:netconf@ietf.org>

      WG Chair: Bert Wijnen
                <mailto:bertietf@bwijnen.net>

      WG Chair: Mehmet Ersue
                <mailto:mehmet.ersue@nsn.com>

      Editor: Andy Bierman
              <mailto:andy.bierman@brocade.com>";

    description
     "This module defines a YANG data model for use with the
      NETCONF protocol that allows the NETCONF client to
      receive common NETCONF base event notifications.

      Copyright (c) 2011 IETF Trust and the persons identified as
      the document authors.  All rights reserved.

      Redistribution and use in source and binary forms, with or
      without modification, is permitted pursuant to, and subject
      to the license terms contained in, the Simplified BSD License
      set forth in Section 4.c of the IETF Trust's Legal Provisions
      Relating to IETF Documents
      (http://trustee.ietf.org/license-info).

      This version of this YANG module is part of RFC XXXX; see
      the RFC itself for full legal notices.";
    // RFC Ed.: replace XXXX with actual RFC number and remove this note

    // RFC Ed.: remove this note
    // Note: extracted from
    // draft-ietf-netconf-system-notifications-07.txt

    revision "2011-12-09" {
      description
        "Initial version.";
      reference
       "RFC XXXX: NETCONF Base Notifications";
    }
    // RFC Ed.: replace XXXX with actual
    // RFC number and remove this note

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   grouping common-session-parms {
     description
       "Common session parameters to identify a
        management session.";

     leaf username {
       type string;
       mandatory true;
       description
         "Name of the user for the session.";
     }

     leaf session-id {
       type nc:session-id-or-zero-type;
       mandatory true;
       description
         "Identifier of the session.
          A NETCONF session MUST be identified by a non-zero value.
          A non-NETCONF session MAY be identified by the value zero.";
     }

     leaf source-host {
       type inet:ip-address;
       description
         "Address of the remote host for the session.";
     }
   }

   grouping changed-by-parms {
     description
       "Common parameters to identify the source
        of a change event, such as a configuration
        or capability change.";

     container changed-by {
       description
         "Indicates the source of the change.
         If caused by internal action, then the
         empty leaf 'server' will be present.
         If caused by a management session, then
         the name, remote host address, and session ID
         of the session that made the change will be reported.";
       choice server-or-user {
         mandatory true;
         leaf server {
           type empty;
           description

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             "If present, the change was caused
              by the server.";
         }

         case by-user {
           uses common-session-parms;
         }
       } // choice server-or-user
     } // container changed-by-parms
   }

   notification netconf-config-change {
     description
       "Generated when the NETCONF server detects that the
        <running> or <startup> configuration datastore
        has been changed by a management session.
        The notification summarizes the edits that
        have been detected.

        The server MAY choose to also generate this
        notification while loading a datastore during the
        boot process for the device.";

     uses changed-by-parms;

     leaf datastore {
       type enumeration {
         enum running {
           description "The <running> datastore has changed.";
         }
         enum startup {
           description "The <startup> datastore has changed";
         }
       }
       default "running";
       description
         "Indicates which configuration datastore has changed.";
     }

     list edit {
       description
         "An edit record SHOULD be present for each distinct
          edit operation that the server has detected on
          the target datastore.  This list MAY be omitted
          if the detailed edit operations are not known.
          The server MAY report entries in this list for
          changes not made by a NETCONF session (e.g., CLI).";

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       leaf target {
         type instance-identifier;
         description
           "Topmost node associated with the configuration change.
            A server SHOULD set this object to the node within
            the datastore that is being altered.  A server MAY
            set this object to one of the ancestors of the actual
            node that was changed, or omit this object, if the
            exact node is not known.";
       }

       leaf operation {
         type nc:edit-operation-type;
         description
            "Type of edit operation performed.
             A server MUST set this object to the NETCONF edit
             operation performed on the target datastore.";
       }
     } // list edit
   } // notification netconf-config-change

   notification netconf-capability-change {
     description
       "Generated when the NETCONF server detects that
        the server capabilities have changed.
        Indicates which capabilities have been added, deleted,
        and/or modified.  The manner in which a server
        capability is changed is outside the scope of this
        document.";

     uses changed-by-parms;

     leaf-list added-capability {
       type inet:uri;
       description
         "List of capabilities that have just been added.";
     }

     leaf-list deleted-capability {
       type inet:uri;
       description
         "List of capabilities that have just been deleted.";
     }

     leaf-list modified-capability {
       type inet:uri;
       description

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         "List of capabilities that have just been modified.
          A capability is considered to be modified if the
          base URI for the capability has not changed, but
          one or more of the parameters encoded at the end of
          the capability URI has changed.
          The new modified value of the complete URI is returned.";
     }
   } // notification netconf-capability-change

   notification netconf-session-start {
     description
       "Generated when a NETCONF server detects that a
        NETCONF session has started.  A server MAY generate
        this event for non-NETCONF management sessions.
        Indicates the identity of the user that started
        the session.";
     uses common-session-parms;
   } // notification netconf-session-start

   notification netconf-session-end {
     description
       "Generated when a NETCONF server detects that a
        NETCONF session has terminated.
        A server MAY optionally generate this event for
        non-NETCONF management sessions. Indicates the
        identity of the user that owned the session,
        and why the session was terminated.";

     uses common-session-parms;

     leaf killed-by {
       when "../termination-reason = 'killed'";
       type nc:session-id-type;
       description
         "The ID of the session that directly caused this session
          to be abnormally terminated.  If this session was abnormally
          terminated by a non-NETCONF session unknown to the server,
          then this leaf will not be present.";
     }

     leaf termination-reason {
       type enumeration {
         enum "closed" {
           description
             "The session was terminated by the client in normal
              fashion, e.g., by the NETCONF <close-session>

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              protocol operation.";
         }
         enum "killed" {
           description
             "The session was terminated in abnormal
              fashion, e.g., by the NETCONF <kill-session>
              protocol operation.";
         }
         enum "dropped" {
           description
             "The session was terminated because the transport layer
              connection was unexpectedly closed.";
         }
         enum "timeout" {
           description
             "The session was terminated because of inactivity,
              e.g., waiting for the <hello> message or <rpc>
              messages.";
         }
         enum "bad-hello" {
           description
             "The client's <hello> message was invalid.";
         }
         enum "other" {
           description
             "The session was terminated for some other reason.";
         }
       }
       mandatory true;
       description
         "Reason the session was terminated.";
     }
   } // notification netconf-session-end

   notification netconf-confirmed-commit {
     description
       "Generated when a NETCONF server detects that a confirmed-commit
        event has occurred.  Indicates the event and the current state
        of the confirmed-commit procedure in progress.";
     reference
       "RFC 6241, section 8.4";

     uses common-session-parms {
       when "../confirm-event != 'timeout'";
     }

     leaf confirm-event {

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       type enumeration {
         enum "start" {
           description
             "The confirmed-commit procedure has started.";
         }
         enum "cancel" {
           description
             "The confirmed-commit procedure has been canceled,
             e.g., due to the session being terminated, or an
             explicit <cancel-commit> operation.";
         }
         enum "timeout" {
           description
             "The confirmed-commit procedure has been canceled,
             due to the confirm-timeout interval expiring.
             The common session parameters will not be present
             in this sub-mode.";
         }
         enum "extend" {
           description
             "The confirmed-commit timeout has been extended,
              e.g., by a new <confirmed-commit> operation.";
         }
         enum "complete" {
           description
             "The confirmed-commit procedure has been completed.";
         }
       }
       mandatory true;
       description
         "Indicates the event that caused the notification.";
     }

     leaf timeout {
       when
        "../confirm-event = 'start' or ../confirm-event = 'extend'";
       type uint32;
       units "seconds";
       description
        "The configured timeout value if the event type
         is 'start' or 'extend'.  This value represents the
         the approximate number of seconds from the event
         time when the 'timeout' event might occur.";
     }
   } // notification netconf-confirmed-commit

 }

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 <CODE ENDS>

3.  IANA Considerations

   This document registers one XML namespace URN in the 'IETF XML
   registry', following the format defined in [RFC3688].

      URI: urn:ietf:params:xml:ns:yang:ietf-netconf-notifications

   Registrant Contact: The IESG.

   XML: N/A, the requested URI is an XML namespace.

   This document registers one module name in the 'YANG Module Names'
   registry, defined in [RFC6020] .

      name: ietf-netconf-notifications
      prefix: ncn
      namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-notifications
      RFC: XXXX // RFC Ed.: replace XXXX and remove this comment

4.  Security Considerations

   The YANG module defined in this memo is designed to be accessed via
   the NETCONF protocol [RFC6241].  The lowest NETCONF layer is the
   secure transport layer and the mandatory-to-implement secure
   transport is SSH, defined in [RFC6242].

   Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via <get>, <get-config>, or
   <notification>) to these data nodes.  These are the subtrees and data
   nodes and their sensitivity/vulnerability:

   /netconf-config-change:
      Event type itself indicates that the system configuration has
      changed.  This event could alert an attacker that specific
      configuration data nodes have been altered.
   /netconf-config-change/changed-by:
      Indicates whether the server or a specific user management session
      made the configuration change.  Identifies the user name,
      session-id, and source host address associated with the
      configuration change, if any.

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   /netconf-config-change/datastore:
      Indicates which datastore has been changed.  This data can be used
      to determine if the non-volatile startup configuration data has
      been changed.
   /netconf-config-change/edit:
      Identifies the specific edit operations and specific datastore
      subtree(s) that have changed.  This data could be used to
      determine if specific server vulnerabilities may now be present.

   /netconf-capability-change:
      Event type itself indicates that the system capabilities have
      changed, and may be now be vulnerable to unspecified attacks.  An
      attacker will likely need to understand the content represented by
      specific capability URI strings.  For example, knowing that a
      packet capture monitoring capability has been added to the system
      might help an attacker identify the device for possible
      unauthorized eavesdropping.
   /netconf-capability-change/changed-by:
      Indicates whether the server or a specific user management session
      made the capability change.  Identifies the user name, session-id,
      and source host address associated with the capability change, if
      any.
   /netconf-capability-change/added-capability:
      Indicates the specific capability URIs that have been added.  This
      data could be used to determine if specific server vulnerabilities
      may now be present.
   /netconf-capability-change/deleted-capability:
      Indicates the specific capability URIs that have been deleted.
      This data could be used to determine if specific server
      vulnerabilities may now be present.
   /netconf-capability-change/modified-capability:
      Indicates the specific capability URIs that have been modified.
      This data could be used to determine if specific server
      vulnerabilities may now be present.

   /netconf-session-start:
      Event type itself indicates that a NETCONF or other management
      session may start altering the device configuration and/or state.
      It may be possible for an attacker to alter the configuration, by
      taking advantage somehow of another session concurrently editing
      an unlocked datastore.
   /netconf-session-start/username:
      Indicates the user name associated with the session.
   /netconf-session-start/source-host:
      Indicates the source host address associated with the session.

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   /netconf-session-end:
      Event type itself indicates that a NETCONF or other management
      session may be finished altering the device configuration.  This
      event could alert an attacker that a datastore may have been
      altered.
   /netconf-session-end/username:
      Indicates the user name associated with the session.
   /netconf-session-end/source-host:
      Indicates the source host address associated with the session.

   /netconf-confirmed-commit:
      Event type itself indicates that the <running> datastore may have
      changed.  This event could alert an attacker that the device
      behavior has changed.
   /netconf-confirmed-commit/username:
      Indicates the user name associated with the session.
   /netconf-confirmed-commit/source-host:
      Indicates the source host address associated with the session.
   /netconf-confirmed-commit/confirm-event:
      Indicates the specific confirmed-commit state change that
      occurred.  A value of 'complete' probably indicates that the
      <running> datastore has changed.
   /netconf-confirmed-commit/timeout:
      Indicates the number of seconds in the future when the <running>
      datastore may change, due to the server reverting to an older
      configuration.

5.  Acknowledgements

   Thanks to Martin Bjorklund, Juergen Schoenwaelder, Kent Watsen, and
   many other members of the NETCONF WG for providing important input to
   this document.

6.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              January 2004.

   [RFC5277]  Chisholm, S. and H. Trevino, "NETCONF Event
              Notifications", RFC 5277, July 2008.

   [RFC6020]  Bjorklund, M., "YANG - A Data Modeling Language for the
              Network Configuration Protocol (NETCONF)", RFC 6020,

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              October 2010.

   [RFC6021]  Schoenwaelder, J., "Common YANG Data Types", RFC 6021,
              October 2010.

   [RFC6241]  Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
              Bierman, "Network Configuration Protocol (NETCONF)",
              RFC 6241, June 2011.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, June 2011.

Appendix A.  Change Log

   -- RFC Ed.: remove this section before publication.

A.1.  06-07

   Add clarifications resulting from IESG review.

   Add text mentioning that ietf-netconf and ietf-inet-types are
   imported to reuse types, to resolve idnits for 'unused reference'
   error.

A.2.  05-06

   Changed YANG statements to canonical order.

   Corrected when-stmt for killed-by leaf.

   Corrected IANA Considerations text.

   Removed redundant value-stmts from confirm-event leaf.

A.3.  04-05

   The module is now ietf-netconf-notifications.  The namespace and
   prefix are now changed as well.

   The target-datastore has been renamed to datastore.

   Clarified behavior for non-NETCONF sessions.

   Minor editorial comments from WG Last Call.

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A.4.  03-04

   Renamed module to NETCONF Base Notifications.  The module is now
   ietf-netconf-base-notifications.  The namespace and prefix are now
   changed as well.

   Changed notifications so a server can report non-NETCONF initiated
   events.

   Replaced security considerations, according to template in RFC 6087.

   Added Acknowledgements section.

A.5.  02-03

   Renamed module back to NETCONF system notifications.  The module is
   now ietf-netconf-system-notifications.  The namespace and prefix are
   now changed as well.

   Leaf user-name is now username, and is now mandatory, to be
   consistent with netconf monitoring module.

   Leaf remote-host is now source-host to be consistent with netconf
   monitoring module.

   The changed-by choice (server-or-user) is now mandatory.

   The netconf-config-change description was updated and leaf target-
   database is now named target-datastore.

   Term 'database' changed to term 'datastore' in text.

   netconf-confirmed-commit: changed uses common-session-parms to use
   when-stmt not refine-stmt.

   netconf-capability-change: updated description text.

A.6.  01-02

   Renamed module NETCONF Events instead of NETCONF system
   notifications.  Note that ietf-netconf-notifications is being
   reserved for the XML content defined in RFC 5277.

   Made changes based on mailing list comments and latest WG consensus.

   Filled in IANA section.

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A.7.  00-01

   Removed sys-startup notification.

   Make changed-by into a grouping, and added usage to sys-config-change
   notification.

   Added target-database leaf to sys-config-change to distinguish
   between running and startup changes.

   Removed 'bad-start' from termination-reason leaf in sys-session-end
   notification.

A.8.  00

   Initial version, based on
   draft-bierman-netconf-system-monitoring-00.txt.

Author's Address

   Andy Bierman
   Brocade

   Email: andy.bierman@brocade.com

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