Internet DRAFT - draft-bierman-netconf-module-tag-ops
draft-bierman-netconf-module-tag-ops
Network Working Group A. Bierman
Internet-Draft YumaWorks
Intended status: Standards Track March 10, 2019
Expires: September 11, 2019
Module Tag Operations
draft-bierman-netconf-module-tag-ops-00
Abstract
This document describes enhancements to existing NETCONF and RESTCONF
(NMDA) operations for using module tags to represent YANG datastore
content. This can simplify usage of these operations by a client.
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 September 11, 2019.
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
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
1.1.1. NMDA . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.2. RESTCONF . . . . . . . . . . . . . . . . . . . . . . 3
1.1.3. YANG . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 4
2. Module Tag Operations . . . . . . . . . . . . . . . . . . . . 4
2.1. Module Tag Filters . . . . . . . . . . . . . . . . . . . 4
2.1.1. NETCONF "module-tag" RPC Input Parameter . . . . . . 5
2.1.2. RESTCONF "module-tag" Query Parameter . . . . . . . . 5
2.2. NACM "module-tags" Rule Type . . . . . . . . . . . . . . 5
3. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 6
3.2. RESTCONF Query Parameter . . . . . . . . . . . . . . . . 10
3.3. RESTCONF Query Parameter Capability . . . . . . . . . . . 10
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
5. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.1. Normative References . . . . . . . . . . . . . . . . . . 12
6.2. Informative References . . . . . . . . . . . . . . . . . 13
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 13
A.1. NETCONF <get-data> Example . . . . . . . . . . . . . . . 13
A.2. RESTCONF GET Example . . . . . . . . . . . . . . . . . . 14
A.3. NACM Example . . . . . . . . . . . . . . . . . . . . . . 15
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
There is a need for standard mechanisms to allow NETCONF [RFC6241]
and RESTCONF [RFC8040] protocol operations, as well as NMDA
operations for NETCONF [RFC8526] and RESTCONF [RFC8527], to utilize
the module tag mapping definitions defined in
[I-D.ietf-netmod-module-tags]. Netconf Access Control rules defined
in [RFC8341] can also utilize module tags to simplify access control
rule configuration.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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1.1.1. NMDA
The following terms are defined in the Network Management Datastore
Architecture (NMDA) [RFC8342]:
o configuration
o client
o datastore
o notification
o operational state
o operational state datastore
o server
1.1.2. RESTCONF
The following terms are defined in [RFC8040]:
o data resource
o target resource
1.1.3. YANG
The following terms are defined in [RFC7950]:
o choice
o container
o data model
o data node
o grouping
o leaf
o leaf-list
o list
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1.2. Tree Diagrams
Tree diagrams used in this document follow the notation defined in
[RFC8340].
2. Module Tag Operations
A module tag is a string associated with a module name. Modules are
associated with the same module tag for the purpose of simplifying
protocol operations, and other tool-specific operations.
The definition and management of module tags is defined in the ietf-
module-tags module. This document defines augmentations to NETCONF
protocol operations that use module tags defined in that module to
represent YANG datastore content instead of a list of module names or
data nodes.
A server vendor and operator can install module to module tag
mappings on a server, using the ietf-module-tags YANG module.
Support for that module is required to utilize the mechanisms defined
in this document.
The following tree diagram shows the 4 separate augmentations defined
in this module:
module: ietf-module-tag-ops
augment /ncds:get-data/ncds:input:
+---w module-tag* tags:tag
augment /nacm:nacm/nacm:rule-list/nacm:rule/nacm:rule-type:
+--:(module-tags)
+--rw module-tag* tags:tag
augment /nc:get-config/nc:input:
+---w module-tag* tags:tag
augment /nc:get/nc:input:
+---w module-tag* tags:tag
2.1. Module Tag Filters
Data retrieval filters based on module tags allow an operator to
easily include only data of specific interest, without having to know
the exact path identifiers for these objects within the datastore.
Module tags can be pre-defined in the YANG module or YANG Module Tags
Registry ([I-D.ietf-netmod-module-tags], sec. 7.2). Module tag
mappings can also be pre-installed by the server vendor, so no
complex setup is required by an operator to use module tag filters.
The NETCONF and RESTCONF protocols do not have any way to select
content by module name at all. In every case, either all content is
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included or specific data node paths have to be provided by the
client to include the associated data instances.
2.1.1. NETCONF "module-tag" RPC Input Parameter
The NETCONF protocol has 2 non-NMDA [RFC6241] retrieval operations
(<get-config> and <get>) and 1 NMDA [RFC8526] retrieval operation
(<get-data>). This document defines a "module-tag" grouping that is
used an additional rpc input parameter for each operation. It can be
applied to all server content that is accessible with these protocol
operations.
2.1.2. RESTCONF "module-tag" Query Parameter
The RESTCONF protocol has a GET operation that allows query
parameters to be provided to modify the retrieval operation. This
document defines a new query parameter named "module-tag" that has
the same semantics as the "module-tag" YANG data node definition. It
also defines a RESTCONF Capability URN for a server to indicate that
this query parameter is supported.
2.2. NACM "module-tags" Rule Type
The Network Configuration Access Control Protocol (NACM) [RFC8341]
allows access control entries to apply to one module or all modules.
This document defines a new "rule-type" case within a "rule" list
entry, which allows the access control rule to apply to all the
modules associated with one or more module tag values.
This new rule type is intended to replace the "module-name" parameter
in the "rule" list entry. Module tag filters are intended to be used
with the default "module-name" value "*" to represent all modules.
This new "module-tags" rule imposes new restrictions on the rule
selection, so it is backward compatible with the definitions in
[RFC8341].
NACM rules using the "module-tag" parameter within the new
"module-tags" case can be applied to configuration data, operational
state, protocol operations and notification events. This rule type
works exactly the same way as the "module-name" leaf within the
"rule" list entry, except it applies to all associated module names,
instead of one.
3. Definitions
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3.1. YANG Module
This module imports definitions from [I-D.ietf-netmod-module-tags],
[RFC6241], [RFC8341], and [RFC8526].
<CODE BEGINS> file "ietf-module-tag-ops@2019-03-10.yang"
module ietf-module-tag-ops {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-module-tag-ops";
prefix mto;
import ietf-module-tags { prefix tags; }
import ietf-netconf { prefix nc; }
import ietf-netconf-acm { prefix nacm; }
import ietf-netconf-nmda { prefix ncds; }
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
Author: Andy Bierman
<mailto:andy@yumaworks.com>";
description
"This module defines enhancements to existing NETCONF
operations for using module tags to represent
YANG datastore content.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
'MAY', and 'OPTIONAL' in this document are to be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here.
Copyright (c) 2019 IETF Trust and the persons identified
as authors of the code. 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).";
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// RFC Ed.: update the date below with the date of RFC publication
// and remove this note.
revision 2019-03-10 {
description
"Initial revision.";
reference
"draft-bierman-netconf-module-tag-ops-00";
}
grouping module-tag {
description
"Contains a reusable module-tag filter parameter";
leaf-list module-tag {
type tags:tag;
description
"Include only data nodes that match the module-tag
value. A data node is matched to a module tag in the
following manner:
1) The module name associated with the data node
is determined according to the protocol and
message encoding.
2) The module name is associated with the specified
module-tag if a 'tag' entry exists within a
/module-tags/module list entry with the same
value as this entry, and a 'masked-tag' entry
does not exist within the same /module-tags/module
list entry.
3) Each child data node is tested in recursive fashion.
If the module name changes from the parent node, then
this procedure is repeated. Once a module name
does not match, then no further descendant nodes
are included.
Multiple module-tag parameters are combined as a
logical OR expression. Matching any tag value will
cause the data node to be included.
It is not an error to include an unknown module-tag
value. Such tag values will simply be treated as a 'false'
match result, when evaluating the filter.
If any module-tag parameters are provided at all,
and there are no matches found, then no data will be
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returned in the response.
The output of all module-tag parameters are
combined with other retrieval filters in a logical
AND expression.
";
}
}
augment /ncds:get-data/ncds:input {
description
"Return data only if it matches according
to the rules specified in the module-tag parameter.";
uses module-tag {
description
"The module-tag values are applied starting at the
top-level YANG data node within the target datastore.";
reference
"RFC 8526: NETCONF Extensions to Support the
Network Management Datastore Architecture; Section 3.1.1";
}
}
augment /nacm:nacm/nacm:rule-list/nacm:rule/nacm:rule-type {
description
"Match datastore content, protocol operations, or
notification events only if the associated module name
matches according to the rules specified in the module-tag
parameter.
If this rule type is used then the associated module-name
parameter needs to be omitted or set to the default value.
Otherwise it will interact with the module-tag parameter
and the specified module-name will only apply if it is
also included in the module-tag parameters provided.";
case module-tags {
uses module-tag {
description
"The module-tag values are applied to the conceptual
document according to the NACM rules, starting at the
top-level YANG data node. This is different in each
access control enforcement procedure phase:
- Incoming RPC Message Validation
The module name of the association protocol operation
is used to match a module-tag parameter.
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- Data Node Access Validation
The module name associated with each data node within
the target datastore, or within non-NMDA operational
state (in an implementation-specific manner).
- Outgoing <notification> Authorization:
The module name of the association notification event
is used to match a module-tag parameter.
";
reference
"RFC 8341: Network Configuration Access Control Model;
Sections 3.2.4, 3.4.4, 3.5.5, 3.4.6";
}
}
}
augment /nc:get-config/nc:input {
status deprecated;
description
"Return configuration data only if it matches according
to the rules specified in the module-tag parameter.";
uses module-tag {
status deprecated;
description
"The module-tag values are applied starting at the
top-level YANG data node within the target datastore.";
reference
"RFC 6241: Network Configuration Protocol; Section 7.1";
}
}
augment /nc:get/nc:input {
status deprecated;
description
"Return data only if it matches according
to the rules specified in the module-tag parameter.";
uses module-tag {
status deprecated;
description
"The module-tag values are applied starting at the
top-level YANG data node within the <running> datastore
for configuration and the top-level YANG data nodes
for all operational state data nodes.";
reference
"RFC 6241: Network Configuration Protocol; Section 7.7";
}
}
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}
<CODE ENDS>
3.2. RESTCONF Query Parameter
The "module-tag" parameter can be used as a query parameter in a
RESTCONF protocol GET operation. This new query parameter can be
applied to any data resource that is retrievable from the server.
This is done using the "{+restconf}/data" resource defined in section
3.3.1 of [RFC8040], or any datastore resource defined in section 3.1
of [RFC8527].
The retrieval filtering is processed exactly the same as the
"module-tag" parameter for NETCONF, defined in Section 3.1.
The module tag filtering starts with the top-level data nodes, the
same as for NETCONF. All data nodes specified in the target resource
are subject to the same module-tag filter test as data nodes within
the target resource.
3.3. RESTCONF Query Parameter Capability
The following RESTCONF Capability URI is defined to indicate that the
module-tag query parameter is supported by a RESTCONF server. It
MUST be advertised as a "capability" in the /restconf-
state/capabilities/capability leaf-list.
The server MUST support the "module-tag" query parameter for GET and
HEAD methods if this capability is advertised.
4. IANA Considerations
This document registers one URI as a namespace in the "IETF XML
Registry" [RFC3688]:
URI: urn:ietf:params:xml:ns:yang:ietf-module-tag-ops
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
This document registers one YANG module in the "YANG Module Names"
registry [RFC6020]:
name: ietf-module-tag-ops
namespace: urn:ietf:params:xml:ns:yang:ietf-module-tag-ops
prefix: sx
// RFC Ed.: replace XXXX with RFC number and remove this note
reference: RFC XXXX
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This document registers one RESTCONF Capability URN in the registry
defined in [RFC8040]:
name: :module-tag
URN: urn:ietf:params:restconf:capability:module-tag:1.0
// RFC Ed.: replace XXXX with RFC number and remove this note
reference: RFC XXXX
5. Security Considerations
The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such
as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer
is the secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer
is HTTPS, and the mandatory-to-implement secure transport is TLS
[RFC8446].
The NETCONF access control model [RFC8341] provides the means to
restrict access for particular NETCONF or RESTCONF users to a
preconfigured subset of all available NETCONF or RESTCONF protocol
operations and content.
There is one data node defined in this YANG module that is
writable/creatable/deletable (i.e., "config true", which is the
default). These data nodes may be considered sensitive or vulnerable
in some network environments. Write operations (e.g., edit-config)
to these data nodes without proper protection can have a negative
effect on network operations. These are the subtrees and data nodes
and their sensitivity/vulnerability:
/nacm/rule-list/rule/module-tag
This object allows an access control rule to be configured based on a
module tag mapping. This object is vurnerable to modifications to
the /module-tags configuration within the server. Care must be taken
not to allow users to modify the /module-tags contents in a way that
will expose protocol access in an unauthorized manner.
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:
/nacm/rule-list/rule/module-tag
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This object allows an access control rule to be configured based on a
module tag mapping. Allowing read access to this object can expose
the access control rule details.
6. References
6.1. Normative References
[I-D.ietf-netmod-module-tags]
Hopps, C., Berger, L., and D. Bogdanovic, "YANG Module
Tags", draft-ietf-netmod-module-tags-07 (work in
progress), March 2019.
[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>.
[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>.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/info/rfc6242>.
[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>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[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>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
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[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
[RFC8526] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "NETCONF Extensions to Support the Network
Management Datastore Architecture", RFC 8526,
DOI 10.17487/RFC8526, March 2019,
<https://www.rfc-editor.org/info/rfc8526>.
[RFC8527] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "RESTCONF Extensions to Support the Network
Management Datastore Architecture", RFC 8527,
DOI 10.17487/RFC8527, March 2019,
<https://www.rfc-editor.org/info/rfc8527>.
6.2. Informative References
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC8348] Bierman, A., Bjorklund, M., Dong, J., and D. Romascanu, "A
YANG Data Model for Hardware Management", RFC 8348,
DOI 10.17487/RFC8348, March 2018,
<https://www.rfc-editor.org/info/rfc8348>.
Appendix A. Examples
A.1. NETCONF <get-data> Example
This example uses the module tag value "ietf:hardware" which is
defined in the YANG Module Tags registry. It is assumed in this case
to be mapped on the server to the "ietf-hardware" module defined in
[RFC8348].
Note that some lines are incorrectly wrapped in the examples below
for display purposes only.
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The server might send the following <get-data> request on the
operational state datastore:
<rpc message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<get-data xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-nmda"
xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
<datastore>ds:operational</datastore>
<mto:module-tag
xmlns:mto="urn:ietf:params:xml:ns:yang:ietf-module-tag-ops">
ietf:hardware
</mto:module-tag>
</get-data>
</rpc>
The server might send the following reply:
<rpc-reply message-id="101"
xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
<data xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-nmda">
<hw:hardware xmlns:hw="urn:ietf:params:xml:ns:yang:ietf-hardware">
<!-- rest of descendant nodes that match the module-tag -->
</hw:hardware>
</data>
</rpc-reply>
A.2. RESTCONF GET Example
This example uses the same module-tag and server assumptions as
Appendix A.1.
The client might send the following request:
GET /restconf/ds/ietf-datastores:operational?module-tag=ietf:hardware\
HTTP/1.1
Host: example.com
Accept: application/yang-data+json
The server might respond as follows. The contents of the "hardware"
container are omitted for brevity.
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HTTP/1.1 200 OK
Date: Thu, 26 Feb 2019 20:56:30 GMT
Server: example-server
Content-Type: application/yang-data+json
{
"ietf-hardware:hardware": {
}
}
A.3. NACM Example
In this example, a module tag rule is created to deny guests all
access to hardware information.
Note that some lines are incorrectly wrapped in the example below for
display purposes only.
<nacm xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-acm">
<rule-list>
<name>guest-acl</name>
<group>guest</group>
<rule>
<name>deny-hw</name>
<mto:module-tag
xmlns:mto="urn:ietf:params:xml:ns:yang:ietf-module-tag-ops">
ietf:hardware</mto:module-tag>
<access-operations>*</access-operations>
<action>deny</action>
<comment>
Do not allow guests to access any hardware information
</comment>
</rule>
</rule-list>
</nacm>
Author's Address
Andy Bierman
YumaWorks
Email: andy@yumaworks.com
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