Internet-Draft | NETCONF Client and Server Models | March 2022 |
Watsen | Expires 8 September 2022 | [Page] |
- Workgroup:
- NETCONF Working Group
- Internet-Draft:
- draft-ietf-netconf-netconf-client-server-25
- Published:
- Intended Status:
- Standards Track
- Expires:
NETCONF Client and Server Models
Abstract
This document defines two YANG modules, one module to configure a NETCONF client and the other module to configure a NETCONF server. Both modules support both the SSH and TLS transport protocols, and support both standard NETCONF and NETCONF Call Home connections.¶
Editorial Note (To be removed by RFC Editor)
This draft contains placeholder values that need to be replaced with finalized values at the time of publication. This note summarizes all of the substitutions that are needed. No other RFC Editor instructions are specified elsewhere in this document.¶
Artwork in this document contains shorthand references to drafts in progress. Please apply the following replacements (note: not all may be present):¶
-
AAAA
--> the assigned RFC value for draft-ietf-netconf-crypto-types¶ -
BBBB
--> the assigned RFC value for draft-ietf-netconf-trust-anchors¶ -
CCCC
--> the assigned RFC value for draft-ietf-netconf-keystore¶ -
DDDD
--> the assigned RFC value for draft-ietf-netconf-tcp-client-server¶ -
EEEE
--> the assigned RFC value for draft-ietf-netconf-ssh-client-server¶ -
FFFF
--> the assigned RFC value for draft-ietf-netconf-tls-client-server¶ -
GGGG
--> the assigned RFC value for draft-ietf-netconf-http-client-server¶ -
HHHH
--> the assigned RFC value for this draft¶
Artwork in this document contains placeholder values for the date of publication of this draft. Please apply the following replacement:¶
-
2022-03-07
--> the publication date of this draft¶
The following Appendix section is to be removed prior to publication:¶
- Appendix A. Change Log¶
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 8 September 2022.¶
Copyright Notice
Copyright (c) 2022 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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶
1. Introduction
This document defines two YANG [RFC7950] modules, one module to configure a NETCONF [RFC6241] client and the other module to configure a NETCONF server. Both modules support both NETCONF over SSH [RFC6242] and NETCONF over TLS [RFC7589] and NETCONF Call Home connections [RFC8071].¶
1.1. Relation to other RFCs
This document presents one or more YANG modules [RFC7950] that are part of a collection of RFCs that work together to, ultimately, enable the configuration of the clients and servers of both the NETCONF [RFC6241] and RESTCONF [RFC8040] protocols.¶
The modules have been defined in a modular fashion to enable their use by other efforts, some of which are known to be in progress at the time of this writing, with many more expected to be defined in time.¶
The normative dependency relationship between the various RFCs in the collection is presented in the below diagram. The labels in the diagram represent the primary purpose provided by each RFC. Hyperlinks to each RFC are provided below the diagram.¶
crypto-types ^ ^ / \ / \ truststore keystore ^ ^ ^ ^ | +---------+ | | | | | | | +------------+ | tcp-client-server | / | | ^ ^ ssh-client-server | | | | ^ tls-client-server | | | ^ ^ http-client-server | | | | | ^ | | | +-----+ +---------+ | | | | | | | | +-----------|--------|--------------+ | | | | | | | | +-----------+ | | | | | | | | | | | | | | | | | netconf-client-server restconf-client-server¶
Label in Diagram | Originating RFC |
---|---|
crypto-types | [I-D.ietf-netconf-crypto-types] |
truststore | [I-D.ietf-netconf-trust-anchors] |
keystore | [I-D.ietf-netconf-keystore] |
tcp-client-server | [I-D.ietf-netconf-tcp-client-server] |
ssh-client-server | [I-D.ietf-netconf-ssh-client-server] |
tls-client-server | [I-D.ietf-netconf-tls-client-server] |
http-client-server | [I-D.ietf-netconf-http-client-server] |
netconf-client-server | [I-D.ietf-netconf-netconf-client-server] |
restconf-client-server | [I-D.ietf-netconf-restconf-client-server] |
1.2. Specification Language
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.¶
1.3. Adherence to the NMDA
This document is compliant with the Network Management Datastore Architecture (NMDA) [RFC8342]. For instance, as described in [I-D.ietf-netconf-trust-anchors] and [I-D.ietf-netconf-keystore], trust anchors and keys installed during manufacturing are expected to appear in <operational>.¶
1.4. Conventions
Various examples used in this document use a placeholder value for binary data that has been base64 encoded (e.g., "BASE64VALUE="). This placeholder value is used as real base64 encoded structures are often many lines long and hence distracting to the example being presented.¶
2. The "ietf-netconf-client" Module
The NETCONF client model presented in this section supports both clients initiating connections to servers, as well as clients listening for connections from servers calling home, using either the SSH and TLS transport protocols.¶
YANG feature statements are used to enable implementations to advertise which potentially uncommon parts of the model the NETCONF client supports.¶
2.1. Data Model Overview
This section provides an overview of the "ietf-netconf-client" module in terms of its features and groupings.¶
2.1.1. Features
The following diagram lists all the "feature" statements defined in the "ietf-netconf-client" module:¶
Features: +-- ssh-initiate +-- tls-initiate +-- ssh-listen +-- tls-listen¶
2.1.2. Groupings
The "ietf-netconf-client" module defines the following "grouping" statements:¶
- netconf-client-grouping¶
- netconf-client-initiate-stack-grouping¶
- netconf-client-listen-stack-grouping¶
- netconf-client-app-grouping¶
Each of these groupings are presented in the following subsections.¶
2.1.2.1. The "netconf-client-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "netconf-client-grouping" grouping:¶
grouping netconf-client-grouping ---> <empty>¶
Comments:¶
- This grouping does not define any nodes, but is maintained so that downstream modules can augment nodes into it if needed.¶
- The "netconf-client-grouping" defines, if it can be called that, the configuration for just "NETCONF" part of a protocol stack. It does not, for instance, define any configuration for the "TCP", "SSH" or "TLS" protocol layers (for that, see Section 2.1.2.2 and Section 2.1.2.3).¶
2.1.2.2. The "netconf-client-initiate-stack-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "netconf-client-initiate-stack-grouping" grouping:¶
grouping netconf-client-initiate-stack-grouping +-- (transport) +--:(ssh) {ssh-initiate}? | +-- ssh | +-- tcp-client-parameters | | +---u tcpc:tcp-client-grouping | +-- ssh-client-parameters | | +---u sshc:ssh-client-grouping | +-- netconf-client-parameters | +--u ncc:netconf-client-grouping +--:(tls) {tls-initiate}? +-- tls +-- tcp-client-parameters | +---u tcpc:tcp-client-grouping +-- tls-client-parameters | +---u tlsc:tls-client-grouping +-- netconf-client-parameters +---u ncc:netconf-client-grouping¶
Comments:¶
- The "netconf-client-initiate-stack-grouping" defines the configuration for a full NETCONF protocol stack, for NETCONF clients that initiate connections to NETCONF servers, as opposed to receiving call-home [RFC8071] connections.¶
- The "transport" choice node enables both the SSH and TLS transports to be configured, with each option enabled by a "feature" statement.¶
-
For the referenced grouping statement(s):¶
- The "tcp-client-grouping" grouping is discussed in Section 3.1.2.1 of [I-D.ietf-netconf-tcp-client-server].¶
- The "ssh-client-grouping" grouping is discussed in Section 3.1.2.1 of [I-D.ietf-netconf-ssh-client-server].¶
- The "tls-client-grouping" grouping is discussed in Section 3.1.2.1 of [I-D.ietf-netconf-tls-client-server].¶
- The "netconf-client-grouping" grouping is discussed in Section 2.1.2.1 in this document.¶
2.1.2.3. The "netconf-client-listen-stack-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "netconf-client-listen-stack-grouping" grouping:¶
grouping netconf-client-listen-stack-grouping +-- (transport) +--:(ssh) {ssh-listen}? | +-- ssh | +-- tcp-server-parameters | | +---u tcps:tcp-server-grouping | +-- ssh-client-parameters | | +---u sshc:ssh-client-grouping | +-- netconf-client-parameters | +--u ncc:netconf-client-grouping +--:(tls) {tls-listen}? +-- tls +-- tcp-server-parameters | +---u tcps:tcp-server-grouping +-- tls-client-parameters | +---u tlsc:tls-client-grouping +-- netconf-client-parameters +---u ncc:netconf-client-grouping¶
Comments:¶
- The "netconf-client-listen-stack-grouping" defines the configuration for a full NETCONF protocol stack, for NETCONF clients that receive call-home [RFC8071] connections from NETCONF servers.¶
- The "transport" choice node enables both the SSH and TLS transports to be configured, with each option enabled by a "feature" statement.¶
-
For the referenced grouping statement(s):¶
- The "tcp-server-grouping" grouping is discussed in Section 4.1.2.1 of [I-D.ietf-netconf-tcp-client-server].¶
- The "ssh-client-grouping" grouping is discussed in Section 3.1.2.1 of [I-D.ietf-netconf-ssh-client-server].¶
- The "tls-client-grouping" grouping is discussed in Section 3.1.2.1 of [I-D.ietf-netconf-tls-client-server].¶
- The "netconf-client-grouping" grouping is discussed in Section 2.1.2.1 in this document.¶
2.1.2.4. The "netconf-client-app-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "netconf-client-app-grouping" grouping:¶
grouping netconf-client-app-grouping +-- initiate! {ssh-initiate or tls-initiate}? | +-- netconf-server* [name] | +-- name? string | +-- endpoints | | +-- endpoint* [name] | | +-- name? string | | +---u netconf-client-initiate-stack-grouping | +-- connection-type | | +-- (connection-type) | | +--:(persistent-connection) | | | +-- persistent! | | +--:(periodic-connection) | | +-- periodic! | | +-- period? uint16 | | +-- anchor-time? yang:date-and-time | | +-- idle-timeout? uint16 | +-- reconnect-strategy | +-- start-with? enumeration | +-- max-attempts? uint8 +-- listen! {ssh-listen or tls-listen}? +-- idle-timeout? uint16 +-- endpoint* [name] +-- name? string +---u netconf-client-listen-stack-grouping¶
Comments:¶
- The "netconf-client-app-grouping" defines the configuration for a NETCONF client that supports both initiating connections to NETCONF servers as well as receiving call-home connections from NETCONF servers.¶
- Both the "initiate" and "listen" subtrees must be enabled by "feature" statements.¶
-
For the referenced grouping statement(s):¶
- The "netconf-client-initiate-stack-grouping" grouping is discussed in Section 2.1.2.2 in this document.¶
- The "netconf-client-listen-stack-grouping" grouping is discussed in Section 2.1.2.3 in this document.¶
2.1.3. Protocol-accessible Nodes
The following tree diagram [RFC8340] lists all the protocol-accessible nodes defined in the "ietf-netconf-client" module:¶
module: ietf-netconf-client +--rw netconf-client +---u netconf-client-app-grouping¶
Comments:¶
- Protocol-accessible nodes are those nodes that are accessible when the module is "implemented", as described in Section 5.6.5 of [RFC7950].¶
- For the "ietf-netconf-client" module, the protocol-accessible nodes are an instance of the "netconf-client-app-grouping" discussed in Section 2.1.2.4 grouping.¶
- The reason for why "netconf-client-app-grouping" exists separate from the protocol-accessible nodes definition is so as to enable instances of netconf-client-app-grouping to be instantiated in other locations, as may be needed or desired by some modules.¶
2.2. Example Usage
The following example illustrates configuring a NETCONF client to initiate connections, using both the SSH and TLS transport protocols, as well as to listen for call-home connections, again using both the SSH and TLS transport protocols.¶
This example is consistent with the examples presented in Section 2.2 of [I-D.ietf-netconf-trust-anchors] and Section 2.2 of [I-D.ietf-netconf-keystore].¶
=============== NOTE: '\' line wrapping per RFC 8792 ================ <netconf-client xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-clie\ nt"> <!-- NETCONF servers to initiate connections to --> <initiate> <netconf-server> <name>corp-fw1</name> <endpoints> <endpoint> <name>corp-fw1.example.com</name> <ssh> <tcp-client-parameters> <remote-address>corp-fw1.example.com</remote-address> <keepalives> <idle-time>15</idle-time> <max-probes>3</max-probes> <probe-interval>30</probe-interval> </keepalives> </tcp-client-parameters> <ssh-client-parameters> <client-identity> <username>foobar</username> <public-key> <keystore-reference>ssh-rsa-key</keystore-referenc\ e> </public-key> </client-identity> <server-authentication> <ca-certs> <truststore-reference>trusted-server-ca-certs</tru\ ststore-reference> </ca-certs> <ee-certs> <truststore-reference>trusted-server-ee-certs</tru\ ststore-reference> </ee-certs> </server-authentication> <keepalives> <max-wait>30</max-wait> <max-attempts>3</max-attempts> </keepalives> </ssh-client-parameters> <netconf-client-parameters> <!-- nothing to configure --> </netconf-client-parameters> </ssh> </endpoint> <endpoint> <name>corp-fw2.example.com</name> <tls> <tcp-client-parameters> <remote-address>corp-fw2.example.com</remote-address> <keepalives> <idle-time>15</idle-time> <max-probes>3</max-probes> <probe-interval>30</probe-interval> </keepalives> </tcp-client-parameters> <tls-client-parameters> <client-identity> <certificate> <keystore-reference> <asymmetric-key>rsa-asymmetric-key</asymmetric-k\ ey> <certificate>ex-rsa-cert</certificate> </keystore-reference> </certificate> </client-identity> <server-authentication> <ca-certs> <truststore-reference>trusted-server-ca-certs</tru\ ststore-reference> </ca-certs> <ee-certs> <truststore-reference>trusted-server-ee-certs</tru\ ststore-reference> </ee-certs> </server-authentication> <keepalives> <test-peer-aliveness> <max-wait>30</max-wait> <max-attempts>3</max-attempts> </test-peer-aliveness> </keepalives> </tls-client-parameters> <netconf-client-parameters> <!-- nothing to configure --> </netconf-client-parameters> </tls> </endpoint> </endpoints> <connection-type> <persistent/> </connection-type> <reconnect-strategy> <start-with>last-connected</start-with> </reconnect-strategy> </netconf-server> </initiate> <!-- endpoints to listen for NETCONF Call Home connections on --> <listen> <endpoint> <name>Intranet-facing SSH listener</name> <ssh> <tcp-server-parameters> <local-address>192.0.2.7</local-address> </tcp-server-parameters> <ssh-client-parameters> <client-identity> <username>foobar</username> <public-key> <keystore-reference>ssh-rsa-key</keystore-reference> </public-key> </client-identity> <server-authentication> <ca-certs> <truststore-reference>trusted-server-ca-certs</trustst\ ore-reference> </ca-certs> <ee-certs> <truststore-reference>trusted-server-ee-certs</trustst\ ore-reference> </ee-certs> <ssh-host-keys> <truststore-reference>trusted-ssh-public-keys</trustst\ ore-reference> </ssh-host-keys> </server-authentication> </ssh-client-parameters> <netconf-client-parameters> <!-- nothing to configure --> </netconf-client-parameters> </ssh> </endpoint> <endpoint> <name>Intranet-facing TLS listener</name> <tls> <tcp-server-parameters> <local-address>192.0.2.7</local-address> </tcp-server-parameters> <tls-client-parameters> <client-identity> <certificate> <keystore-reference> <asymmetric-key>rsa-asymmetric-key</asymmetric-key> <certificate>ex-rsa-cert</certificate> </keystore-reference> </certificate> </client-identity> <server-authentication> <ca-certs> <truststore-reference>trusted-server-ca-certs</trustst\ ore-reference> </ca-certs> <ee-certs> <truststore-reference>trusted-server-ee-certs</trustst\ ore-reference> </ee-certs> </server-authentication> <keepalives> <peer-allowed-to-send/> </keepalives> </tls-client-parameters> <netconf-client-parameters> <!-- nothing to configure --> </netconf-client-parameters> </tls> </endpoint> </listen> </netconf-client>¶
2.3. YANG Module
This YANG module has normative references to [RFC6242], [RFC6991], [RFC7589], [RFC8071], [I-D.ietf-netconf-tcp-client-server], [I-D.ietf-netconf-ssh-client-server], and [I-D.ietf-netconf-tls-client-server].¶
<CODE BEGINS> file "ietf-netconf-client@2022-03-07.yang"¶
module ietf-netconf-client { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-client"; prefix ncc; import ietf-yang-types { prefix yang; reference "RFC 6991: Common YANG Data Types"; } import ietf-tcp-client { prefix tcpc; reference "RFC DDDD: YANG Groupings for TCP Clients and TCP Servers"; } import ietf-tcp-server { prefix tcps; reference "RFC DDDD: YANG Groupings for TCP Clients and TCP Servers"; } import ietf-ssh-client { prefix sshc; revision-date 2022-03-07; // stable grouping definitions reference "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers"; } import ietf-tls-client { prefix tlsc; revision-date 2022-03-07; // stable grouping definitions reference "RFC FFFF: YANG Groupings for TLS Clients and TLS Servers"; } organization "IETF NETCONF (Network Configuration) Working Group"; contact "WG Web: https://datatracker.ietf.org/wg/netconf WG List: NETCONF WG list <mailto:netconf@ietf.org> Author: Kent Watsen <mailto:kent+ietf@watsen.net> Author: Gary Wu <mailto:garywu@cisco.com>"; description "This module contains a collection of YANG definitions for configuring NETCONF clients. Copyright (c) 2021 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 Revised BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC HHHH (https://www.rfc-editor.org/info/rfcHHHH); see the RFC itself for full legal notices. 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."; revision 2022-03-07 { description "Initial version"; reference "RFC HHHH: NETCONF Client and Server Models"; } // Features feature ssh-initiate { description "The 'ssh-initiate' feature indicates that the NETCONF client supports initiating SSH connections to NETCONF servers."; reference "RFC 6242: Using the NETCONF Protocol over Secure Shell (SSH)"; } feature tls-initiate { description "The 'tls-initiate' feature indicates that the NETCONF client supports initiating TLS connections to NETCONF servers."; reference "RFC 7589: Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication"; } feature ssh-listen { description "The 'ssh-listen' feature indicates that the NETCONF client supports opening a port to listen for incoming NETCONF server call-home SSH connections."; reference "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; } feature tls-listen { description "The 'tls-listen' feature indicates that the NETCONF client supports opening a port to listen for incoming NETCONF server call-home TLS connections."; reference "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; } // Groupings grouping netconf-client-grouping { description "A reusable grouping for configuring a NETCONF client without any consideration for how underlying transport sessions are established. This grouping currently does not define any nodes."; } grouping netconf-client-initiate-stack-grouping { description "A reusable grouping for configuring a NETCONF client 'initiate' protocol stack for a single connection."; choice transport { mandatory true; description "Selects between available transports."; case ssh { if-feature "ssh-initiate"; container ssh { description "Specifies IP and SSH specific configuration for the connection."; container tcp-client-parameters { description "A wrapper around the TCP client parameters to avoid name collisions."; uses tcpc:tcp-client-grouping { refine "remote-port" { default "830"; description "The NETCONF client will attempt to connect to the IANA-assigned well-known port value for 'netconf-ssh' (830) if no value is specified."; } } } container ssh-client-parameters { description "A wrapper around the SSH client parameters to avoid name collisions."; uses sshc:ssh-client-grouping; } container netconf-client-parameters { description "A wrapper around the NETCONF client parameters to avoid name collisions."; uses ncc:netconf-client-grouping; } } } case tls { if-feature "tls-initiate"; container tls { description "Specifies IP and TLS specific configuration for the connection."; container tcp-client-parameters { description "A wrapper around the TCP client parameters to avoid name collisions."; uses tcpc:tcp-client-grouping { refine "remote-port" { default "6513"; description "The NETCONF client will attempt to connect to the IANA-assigned well-known port value for 'netconf-tls' (6513) if no value is specified."; } } } container tls-client-parameters { must client-identity { description "NETCONF/TLS clients MUST pass some authentication credentials."; } description "A wrapper around the TLS client parameters to avoid name collisions."; uses tlsc:tls-client-grouping; } container netconf-client-parameters { description "A wrapper around the NETCONF client parameters to avoid name collisions."; uses ncc:netconf-client-grouping; } } } } } // netconf-client-initiate-stack-grouping grouping netconf-client-listen-stack-grouping { description "A reusable grouping for configuring a NETCONF client 'listen' protocol stack for a single connection. The 'listen' stack supports call home connections, as described in RFC 8071"; reference "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; choice transport { mandatory true; description "Selects between available transports."; case ssh { if-feature "ssh-listen"; container ssh { description "SSH-specific listening configuration for inbound connections."; container tcp-server-parameters { description "A wrapper around the TCP server parameters to avoid name collisions."; uses tcps:tcp-server-grouping { refine "local-port" { default "4334"; description "The NETCONF client will listen on the IANA- assigned well-known port for 'netconf-ch-ssh' (4334) if no value is specified."; } } } container ssh-client-parameters { description "A wrapper around the SSH client parameters to avoid name collisions."; uses sshc:ssh-client-grouping; } container netconf-client-parameters { description "A wrapper around the NETCONF client parameters to avoid name collisions."; uses ncc:netconf-client-grouping; } } } case tls { if-feature "tls-listen"; container tls { description "TLS-specific listening configuration for inbound connections."; container tcp-server-parameters { description "A wrapper around the TCP server parameters to avoid name collisions."; uses tcps:tcp-server-grouping { refine "local-port" { default "4334"; description "The NETCONF client will listen on the IANA- assigned well-known port for 'netconf-ch-ssh' (4334) if no value is specified."; } } } container tls-client-parameters { must client-identity { description "NETCONF/TLS clients MUST pass some authentication credentials."; } description "A wrapper around the TLS client parameters to avoid name collisions."; uses tlsc:tls-client-grouping; } container netconf-client-parameters { description "A wrapper around the NETCONF client parameters to avoid name collisions."; uses ncc:netconf-client-grouping; } } } } } // netconf-client-listen-stack-grouping grouping netconf-client-app-grouping { description "A reusable grouping for configuring a NETCONF client application that supports both 'initiate' and 'listen' protocol stacks for a multiplicity of connections."; container initiate { if-feature "ssh-initiate or tls-initiate"; presence "Indicates that client-initiated connections have been configured. This statement is present so the mandatory descendant nodes do not imply that this node must be configured."; description "Configures client initiating underlying TCP connections."; list netconf-server { key "name"; min-elements 1; description "List of NETCONF servers the NETCONF client is to maintain simultaneous connections with."; leaf name { type string; description "An arbitrary name for the NETCONF server."; } container endpoints { description "Container for the list of endpoints."; list endpoint { key "name"; min-elements 1; ordered-by user; description "A user-ordered list of endpoints that the NETCONF client will attempt to connect to in the specified sequence. Defining more than one enables high-availability."; leaf name { type string; description "An arbitrary name for the endpoint."; } uses netconf-client-initiate-stack-grouping; } // list endpoint } // container endpoints container connection-type { description "Indicates the NETCONF client's preference for how the NETCONF connection is maintained."; choice connection-type { mandatory true; description "Selects between available connection types."; case persistent-connection { container persistent { presence "Indicates that a persistent connection is to be maintained."; description "Maintain a persistent connection to the NETCONF server. If the connection goes down, immediately start trying to reconnect to the NETCONF server, using the reconnection strategy. This connection type minimizes any NETCONF server to NETCONF client data-transfer delay, albeit at the expense of holding resources longer."; } } case periodic-connection { container periodic { presence "Indicates that a periodic connection is to be maintained."; description "Periodically connect to the NETCONF server. This connection type increases resource utilization, albeit with increased delay in NETCONF server to NETCONF client interactions. The NETCONF client should close the underlying TCP connection upon completing planned activities. In the case that the previous connection is still active, establishing a new connection is NOT RECOMMENDED."; leaf period { type uint16; units "minutes"; default "60"; description "Duration of time between periodic connections."; } leaf anchor-time { type yang:date-and-time { // constrained to minute-level granularity pattern '\d{4}-\d{2}-\d{2}T\d{2}:\d{2}' + '(Z|[\+\-]\d{2}:\d{2})'; } description "Designates a timestamp before or after which a series of periodic connections are determined. The periodic connections occur at a whole multiple interval from the anchor time. For example, for an anchor time is 15 minutes past midnight and a period interval of 24 hours, then a periodic connection will occur 15 minutes past midnight everyday."; } leaf idle-timeout { type uint16; units "seconds"; default 120; // two minutes description "Specifies the maximum number of seconds that a NETCONF session may remain idle. A NETCONF session will be dropped if it is idle for an interval longer then this number of seconds. If set to zero, then the NETCONF client will never drop a session because it is idle."; } } } } } container reconnect-strategy { description "The reconnection strategy directs how a NETCONF client reconnects to a NETCONF server, after discovering its connection to the server has dropped, even if due to a reboot. The NETCONF client starts with the specified endpoint and tries to connect to it max-attempts times before trying the next endpoint in the list (round robin)."; leaf start-with { type enumeration { enum first-listed { description "Indicates that reconnections should start with the first endpoint listed."; } enum last-connected { description "Indicates that reconnections should start with the endpoint last connected to. If no previous connection has ever been established, then the first endpoint configured is used. NETCONF clients SHOULD be able to remember the last endpoint connected to across reboots."; } enum random-selection { description "Indicates that reconnections should start with a random endpoint."; } } default "first-listed"; description "Specifies which of the NETCONF server's endpoints the NETCONF client should start with when trying to connect to the NETCONF server."; } leaf max-attempts { type uint8 { range "1..max"; } default "3"; description "Specifies the number times the NETCONF client tries to connect to a specific endpoint before moving on to the next endpoint in the list (round robin)."; } } } // netconf-server } // initiate container listen { if-feature "ssh-listen or tls-listen"; presence "Indicates that client-listening ports have been configured. This statement is present so the mandatory descendant nodes do not imply that this node must be configured."; description "Configures the client to accept call-home TCP connections."; leaf idle-timeout { type uint16; units "seconds"; default "3600"; // one hour description "Specifies the maximum number of seconds that a NETCONF session may remain idle. A NETCONF session will be dropped if it is idle for an interval longer than this number of seconds. If set to zero, then the server will never drop a session because it is idle. Sessions that have a notification subscription active are never dropped."; } list endpoint { key "name"; min-elements 1; description "List of endpoints to listen for NETCONF connections."; leaf name { type string; description "An arbitrary name for the NETCONF listen endpoint."; } uses netconf-client-listen-stack-grouping; } // endpoint } // listen } // netconf-client-app-grouping // Protocol accessible node for clients that implement this module. container netconf-client { uses netconf-client-app-grouping; description "Top-level container for NETCONF client configuration."; } }¶
<CODE ENDS>¶
3. The "ietf-netconf-server" Module
The NETCONF server model presented in this section supports both listening for connections as well as initiating call-home connections, using either the SSH and TLS transport protocols.¶
YANG feature statements are used to enable implementations to advertise which potentially uncommon parts of the model the NETCONF server supports.¶
3.1. Data Model Overview
This section provides an overview of the "ietf-netconf-server" module in terms of its features and groupings.¶
3.1.1. Features
The following diagram lists all the "feature" statements defined in the "ietf-netconf-server" module:¶
Features: +-- ssh-listen +-- tls-listen +-- ssh-call-home +-- tls-call-home¶
3.1.2. Groupings
The "ietf-netconf-server" module defines the following "grouping" statements:¶
- netconf-server-grouping¶
- netconf-server-listen-stack-grouping¶
- netconf-server-callhome-stack-grouping¶
- netconf-server-app-grouping¶
Each of these groupings are presented in the following subsections.¶
3.1.2.1. The "netconf-server-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "netconf-server-grouping" grouping:¶
grouping netconf-server-grouping +-- client-identity-mappings +---u x509c2n:cert-to-name¶
Comments:¶
- The "netconf-server-grouping" defines the configuration for just "NETCONF" part of a protocol stack. It does not, for instance, define any configuration for the "TCP", "SSH" or "TLS" protocol layers (for that, see Section 3.1.2.2 and Section 3.1.2.3).¶
- The "client-identity-mappings" node, which must be enabled by "feature" statements, defines a mapping from certificate fields to NETCONF user names.¶
-
For the referenced grouping statement(s):¶
- The "cert-to-name" grouping is discussed in Section 4.1 of [RFC7407].¶
3.1.2.2. The "netconf-server-listen-stack-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "netconf-server-listen-stack-grouping" grouping:¶
grouping netconf-server-listen-stack-grouping +-- (transport) +--:(ssh) {ssh-listen}? | +-- ssh | +-- tcp-server-parameters | | +---u tcps:tcp-server-grouping | +-- ssh-server-parameters | | +---u sshs:ssh-server-grouping | +-- netconf-server-parameters | +---u ncs:netconf-server-grouping +--:(tls) {tls-listen}? +-- tls +-- tcp-server-parameters | +---u tcps:tcp-server-grouping +-- tls-server-parameters | +---u tlss:tls-server-grouping +-- netconf-server-parameters +---u ncs:netconf-server-grouping¶
Comments:¶
- The "netconf-server-listen-stack-grouping" defines the configuration for a full NETCONF protocol stack for NETCONF servers that listen for standard connections from NETCONF clients, as opposed to initiating call-home [RFC8071] connections.¶
- The "transport" choice node enables both the SSH and TLS transports to be configured, with each option enabled by a "feature" statement.¶
-
For the referenced grouping statement(s):¶
- The "tcp-server-grouping" grouping is discussed in Section 4.1.2.1 of [I-D.ietf-netconf-tcp-client-server].¶
- The "ssh-server-grouping" grouping is discussed in Section 4.1.2.1 of [I-D.ietf-netconf-ssh-client-server].¶
- The "tls-server-grouping" grouping is discussed in Section 4.1.2.1 of [I-D.ietf-netconf-tls-client-server].¶
- The "netconf-server-grouping" is discussed in Section 3.1.2.1 of this document.¶
3.1.2.3. The "netconf-server-callhome-stack-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "netconf-server-callhome-stack-grouping" grouping:¶
grouping netconf-server-callhome-stack-grouping +-- (transport) +--:(ssh) {ssh-call-home}? | +-- ssh | +-- tcp-client-parameters | | +---u tcpc:tcp-client-grouping | +-- ssh-server-parameters | | +---u sshs:ssh-server-grouping | +-- netconf-server-parameters | +---u ncs:netconf-server-grouping +--:(tls) {tls-call-home}? +-- tls +-- tcp-client-parameters | +---u tcpc:tcp-client-grouping +-- tls-server-parameters | +---u tlss:tls-server-grouping +-- netconf-server-parameters +---u ncs:netconf-server-grouping¶
Comments:¶
- The "netconf-server-callhome-stack-grouping" defines the configuration for a full NETCONF protocol stack, for NETCONF servers that initiate call-home [RFC8071] connections to NETCONF clients.¶
- The "transport" choice node enables both the SSH and TLS transports to be configured, with each option enabled by a "feature" statement.¶
-
For the referenced grouping statement(s):¶
- The "tcp-client-grouping" grouping is discussed in Section 3.1.2.1 of [I-D.ietf-netconf-tcp-client-server].¶
- The "ssh-server-grouping" grouping is discussed in Section 4.1.2.1 of [I-D.ietf-netconf-ssh-client-server].¶
- The "tls-server-grouping" grouping is discussed in Section 4.1.2.1 of [I-D.ietf-netconf-tls-client-server].¶
- The "netconf-server-grouping" is discussed in Section 3.1.2.1 of this document.¶
3.1.2.4. The "netconf-server-app-grouping" Grouping
The following tree diagram [RFC8340] illustrates the "netconf-server-app-grouping" grouping:¶
grouping netconf-server-app-grouping +-- listen! {ssh-listen or tls-listen}? | +-- idle-timeout? uint16 | +-- endpoint* [name] | +-- name? string | +---u netconf-server-listen-stack-grouping +-- call-home! {ssh-call-home or tls-call-home}? +-- netconf-client* [name] +-- name? string +-- endpoints | +-- endpoint* [name] | +-- name? string | +---u netconf-server-callhome-stack-grouping +-- connection-type | +-- (connection-type) | +--:(persistent-connection) | | +-- persistent! | +--:(periodic-connection) | +-- periodic! | +-- period? uint16 | +-- anchor-time? yang:date-and-time | +-- idle-timeout? uint16 +-- reconnect-strategy +-- start-with? enumeration +-- max-attempts? uint8¶
Comments:¶
- The "netconf-server-app-grouping" defines the configuration for a NETCONF server that supports both listening for connections from NETCONF clients as well as initiating call-home connections to NETCONF clients.¶
- Both the "listen" and "call-home" subtrees must be enabled by "feature" statements.¶
-
For the referenced grouping statement(s):¶
- The "netconf-server-listen-stack-grouping" grouping is discussed in Section 3.1.2.2 in this document.¶
- The "netconf-server-callhome-stack-grouping" grouping is discussed in Section 3.1.2.3 in this document.¶
3.1.3. Protocol-accessible Nodes
The following tree diagram [RFC8340] lists all the protocol-accessible nodes defined in the "ietf-netconf-server" module:¶
module: ietf-netconf-server +--rw netconf-server +---u netconf-server-app-grouping¶
Comments:¶
- Protocol-accessible nodes are those nodes that are accessible when the module is "implemented", as described in Section 5.6.5 of [RFC7950].¶
- For the "ietf-netconf-server" module, the protocol-accessible nodes are an instance of the "netconf-server-app-grouping" discussed in Section 3.1.2.4 grouping.¶
- The reason for why "netconf-server-app-grouping" exists separate from the protocol-accessible nodes definition is so as to enable instances of netconf-server-app-grouping to be instantiated in other locations, as may be needed or desired by some modules.¶
3.2. Example Usage
The following example illustrates configuring a NETCONF server to listen for NETCONF client connections using both the SSH and TLS transport protocols, as well as configuring call-home to two NETCONF clients, one using SSH and the other using TLS.¶
This example is consistent with the examples presented in Section 2.2 of [I-D.ietf-netconf-trust-anchors] and Section 2.2 of [I-D.ietf-netconf-keystore].¶
=============== NOTE: '\' line wrapping per RFC 8792 ================ <netconf-server xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-serv\ er"> <!-- endpoints to listen for NETCONF connections on --> <listen> <endpoint> <!-- listening for SSH connections --> <name>netconf/ssh</name> <ssh> <tcp-server-parameters> <local-address>192.0.2.7</local-address> </tcp-server-parameters> <ssh-server-parameters> <server-identity> <host-key> <name>deployment-specific-certificate</name> <public-key> <keystore-reference>ssh-rsa-key</keystore-reference> </public-key> </host-key> </server-identity> <client-authentication> </client-authentication> </ssh-server-parameters> <netconf-server-parameters> <!-- nothing to configure --> </netconf-server-parameters> </ssh> </endpoint> <endpoint> <!-- listening for TLS sessions --> <name>netconf/tls</name> <tls> <tcp-server-parameters> <local-address>192.0.2.7</local-address> </tcp-server-parameters> <tls-server-parameters> <server-identity> <certificate> <keystore-reference> <asymmetric-key>rsa-asymmetric-key</asymmetric-key> <certificate>ex-rsa-cert</certificate> </keystore-reference> </certificate> </server-identity> <client-authentication> <ca-certs> <truststore-reference>trusted-client-ca-certs</trustst\ ore-reference> </ca-certs> <ee-certs> <truststore-reference>trusted-client-ee-certs</trustst\ ore-reference> </ee-certs> </client-authentication> <keepalives> <peer-allowed-to-send/> </keepalives> </tls-server-parameters> <netconf-server-parameters> <client-identity-mappings> <cert-to-name> <id>1</id> <fingerprint>11:0A:05:11:00</fingerprint> <map-type>x509c2n:specified</map-type> <name>scooby-doo</name> </cert-to-name> <cert-to-name> <id>2</id> <map-type>x509c2n:san-any</map-type> </cert-to-name> </client-identity-mappings> </netconf-server-parameters> </tls> </endpoint> </listen> <!-- calling home to SSH and TLS based NETCONF clients --> <call-home> <netconf-client> <!-- SSH-based client --> <name>config-mgr</name> <endpoints> <endpoint> <name>east-data-center</name> <ssh> <tcp-client-parameters> <remote-address>east.config-mgr.example.com</remote-ad\ dress> <keepalives> <idle-time>15</idle-time> <max-probes>3</max-probes> <probe-interval>30</probe-interval> </keepalives> </tcp-client-parameters> <ssh-server-parameters> <server-identity> <host-key> <name>deployment-specific-certificate</name> <public-key> <keystore-reference>ssh-rsa-key</keystore-refere\ nce> </public-key> </host-key> </server-identity> </ssh-server-parameters> <netconf-server-parameters> <!-- nothing to configure --> </netconf-server-parameters> </ssh> </endpoint> <endpoint> <name>west-data-center</name> <ssh> <tcp-client-parameters> <remote-address>west.config-mgr.example.com</remote-ad\ dress> </tcp-client-parameters> <ssh-server-parameters> <server-identity> <host-key> <name>deployment-specific-certificate</name> <public-key> <keystore-reference>ssh-rsa-key</keystore-refere\ nce> </public-key> </host-key> </server-identity> </ssh-server-parameters> <netconf-server-parameters> <!-- nothing to configure --> </netconf-server-parameters> </ssh> </endpoint> </endpoints> <connection-type> <periodic> <idle-timeout>300</idle-timeout> <period>60</period> </periodic> </connection-type> <reconnect-strategy> <start-with>last-connected</start-with> <max-attempts>3</max-attempts> </reconnect-strategy> </netconf-client> <netconf-client> <!-- TLS-based client --> <name>data-collector</name> <endpoints> <endpoint> <name>east-data-center</name> <tls> <tcp-client-parameters> <remote-address>east.analytics.example.com</remote-add\ ress> <keepalives> <idle-time>15</idle-time> <max-probes>3</max-probes> <probe-interval>30</probe-interval> </keepalives> </tcp-client-parameters> <tls-server-parameters> <server-identity> <certificate> <keystore-reference> <asymmetric-key>rsa-asymmetric-key</asymmetric-k\ ey> <certificate>ex-rsa-cert</certificate> </keystore-reference> </certificate> </server-identity> <client-authentication> <ca-certs> <truststore-reference>trusted-client-ca-certs</tru\ ststore-reference> </ca-certs> <ee-certs> <truststore-reference>trusted-client-ee-certs</tru\ ststore-reference> </ee-certs> </client-authentication> <keepalives> <test-peer-aliveness> <max-wait>30</max-wait> <max-attempts>3</max-attempts> </test-peer-aliveness> </keepalives> </tls-server-parameters> <netconf-server-parameters> <client-identity-mappings> <cert-to-name> <id>1</id> <fingerprint>11:0A:05:11:00</fingerprint> <map-type>x509c2n:specified</map-type> <name>scooby-doo</name> </cert-to-name> <cert-to-name> <id>2</id> <map-type>x509c2n:san-any</map-type> </cert-to-name> </client-identity-mappings> </netconf-server-parameters> </tls> </endpoint> <endpoint> <name>west-data-center</name> <tls> <tcp-client-parameters> <remote-address>west.analytics.example.com</remote-add\ ress> <keepalives> <idle-time>15</idle-time> <max-probes>3</max-probes> <probe-interval>30</probe-interval> </keepalives> </tcp-client-parameters> <tls-server-parameters> <server-identity> <certificate> <keystore-reference> <asymmetric-key>rsa-asymmetric-key</asymmetric-k\ ey> <certificate>ex-rsa-cert</certificate> </keystore-reference> </certificate> </server-identity> <client-authentication> <ca-certs> <truststore-reference>trusted-client-ca-certs</tru\ ststore-reference> </ca-certs> <ee-certs> <truststore-reference>trusted-client-ee-certs</tru\ ststore-reference> </ee-certs> </client-authentication> <keepalives> <test-peer-aliveness> <max-wait>30</max-wait> <max-attempts>3</max-attempts> </test-peer-aliveness> </keepalives> </tls-server-parameters> <netconf-server-parameters> <client-identity-mappings> <cert-to-name> <id>1</id> <fingerprint>11:0A:05:11:00</fingerprint> <map-type>x509c2n:specified</map-type> <name>scooby-doo</name> </cert-to-name> <cert-to-name> <id>2</id> <map-type>x509c2n:san-any</map-type> </cert-to-name> </client-identity-mappings> </netconf-server-parameters> </tls> </endpoint> </endpoints> <connection-type> <persistent/> </connection-type> <reconnect-strategy> <start-with>first-listed</start-with> <max-attempts>3</max-attempts> </reconnect-strategy> </netconf-client> </call-home> </netconf-server>¶
3.3. YANG Module
This YANG module has normative references to [RFC6242], [RFC6991], [RFC7407], [RFC7589], [RFC8071], [I-D.ietf-netconf-tcp-client-server], [I-D.ietf-netconf-ssh-client-server], and [I-D.ietf-netconf-tls-client-server].¶
<CODE BEGINS> file "ietf-netconf-server@2022-03-07.yang"¶
module ietf-netconf-server { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-server"; prefix ncs; import ietf-yang-types { prefix yang; reference "RFC 6991: Common YANG Data Types"; } import ietf-x509-cert-to-name { prefix x509c2n; reference "RFC 7407: A YANG Data Model for SNMP Configuration"; } import ietf-tcp-client { prefix tcpc; reference "RFC DDDD: YANG Groupings for TCP Clients and TCP Servers"; } import ietf-tcp-server { prefix tcps; reference "RFC DDDD: YANG Groupings for TCP Clients and TCP Servers"; } import ietf-ssh-common { prefix sshcmn; revision-date 2022-03-07; // stable grouping definitions reference "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers"; } import ietf-ssh-server { prefix sshs; revision-date 2022-03-07; // stable grouping definitions reference "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers"; } import ietf-tls-server { prefix tlss; revision-date 2022-03-07; // stable grouping definitions reference "RFC FFFF: YANG Groupings for TLS Clients and TLS Servers"; } organization "IETF NETCONF (Network Configuration) Working Group"; contact "WG Web: https://datatracker.ietf.org/wg/netconf WG List: NETCONF WG list <mailto:netconf@ietf.org> Author: Kent Watsen <mailto:kent+ietf@watsen.net> Author: Gary Wu <mailto:garywu@cisco.com> Author: Juergen Schoenwaelder <mailto:j.schoenwaelder@jacobs-university.de>"; description "This module contains a collection of YANG definitions for configuring NETCONF servers. Copyright (c) 2021 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 Revised BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC HHHH (https://www.rfc-editor.org/info/rfcHHHH); see the RFC itself for full legal notices. 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."; revision 2022-03-07 { description "Initial version"; reference "RFC HHHH: NETCONF Client and Server Models"; } // Features feature ssh-listen { description "The 'ssh-listen' feature indicates that the NETCONF server supports opening a port to accept NETCONF over SSH client connections."; reference "RFC 6242: Using the NETCONF Protocol over Secure Shell (SSH)"; } feature tls-listen { description "The 'tls-listen' feature indicates that the NETCONF server supports opening a port to accept NETCONF over TLS client connections."; reference "RFC 7589: Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication"; } feature ssh-call-home { description "The 'ssh-call-home' feature indicates that the NETCONF server supports initiating a NETCONF over SSH call home connection to NETCONF clients."; reference "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; } feature tls-call-home { description "The 'tls-call-home' feature indicates that the NETCONF server supports initiating a NETCONF over TLS call home connection to NETCONF clients."; reference "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; } // Groupings grouping netconf-server-grouping { description "A reusable grouping for configuring a NETCONF server without any consideration for how underlying transport sessions are established. Note that this grouping uses a fairly typical descendant node name such that a stack of 'uses' statements will have name conflicts. It is intended that the consuming data model will resolve the issue by wrapping the 'uses' statement in a container called, e.g., 'netconf-server-parameters'. This model purposely does not do this itself so as to provide maximum flexibility to consuming models."; container client-identity-mappings { description "Specifies mappings through which NETCONF client X.509 certificates are used to determine a NETCONF username, per RFC 7407. For TLS-based transports, if no matching and valid cert-to-name list entry can be found, then the NETCONF server MUST close the connection, and MUST NOT accept NETCONF messages over it, per Section 7 in RFC 7589. For SSH-based transports, a matching cert-to-name entry overrides the username provided by the SSH implementation, consistent with the second paragraph of Section 3 in RFC 6242."; reference "RFC 6242: Using the NETCONF Protocol over Secure Shell (SSH) RFC 7589: Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication"; uses x509c2n:cert-to-name { refine "cert-to-name/fingerprint" { mandatory false; description "A 'fingerprint' value does not need to be specified when the 'cert-to-name' mapping is independent of fingerprint matching. A 'cert-to-name' having no fingerprint value will match any client certificate and therefore should only be present at the end of the user-ordered 'cert-to-name' list."; } } } } grouping netconf-server-listen-stack-grouping { description "A reusable grouping for configuring a NETCONF server 'listen' protocol stack for a single connection."; choice transport { mandatory true; description "Selects between available transports."; case ssh { if-feature "ssh-listen"; container ssh { description "SSH-specific listening configuration for inbound connections."; container tcp-server-parameters { description "A wrapper around the TCP client parameters to avoid name collisions."; uses tcps:tcp-server-grouping { refine "local-port" { default "830"; description "The NETCONF server will listen on the IANA-assigned well-known port value for 'netconf-ssh' (830) if no value is specified."; } } } container ssh-server-parameters { description "A wrapper around the SSH server parameters to avoid name collisions."; uses sshs:ssh-server-grouping; } container netconf-server-parameters { description "A wrapper around the NETCONF server parameters to avoid name collisions."; uses ncs:netconf-server-grouping { refine "client-identity-mappings" { if-feature "sshcmn:ssh-x509-certs"; description "Augments in an 'if-feature' statement ensuring the 'client-identity-mappings' descendant is enabled only when SSH supports X.509 certificates."; } augment "client-identity-mappings" { description "Adds a flag indicating if a cert-to-name is required."; leaf mapping-required { type boolean; description "Indicates that the cert-to-name mapping is required (i.e., the SSH-level username is ignored)."; } } } } } } case tls { if-feature "tls-listen"; container tls { description "TLS-specific listening configuration for inbound connections."; container tcp-server-parameters { description "A wrapper around the TCP client parameters to avoid name collisions."; uses tcps:tcp-server-grouping { refine "local-port" { default "6513"; description "The NETCONF server will listen on the IANA-assigned well-known port value for 'netconf-tls' (6513) if no value is specified."; } } } container tls-server-parameters { description "A wrapper around the TLS server parameters to avoid name collisions."; uses tlss:tls-server-grouping { refine "client-authentication" { must 'ca-certs or ee-certs'; description "NETCONF/TLS servers MUST validate client certificates. This configures certificates at the socket-level (i.e. bags), more discriminating client-certificate checks SHOULD be implemented by the application."; reference "RFC 7589: Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication"; } } } container netconf-server-parameters { description "A wrapper around the NETCONF server parameters to avoid name collisions."; uses ncs:netconf-server-grouping { refine "client-identity-mappings/cert-to-name" { min-elements 1; description "The TLS transport requires a mapping."; } } } } } } } grouping netconf-server-callhome-stack-grouping { description "A reusable grouping for configuring a NETCONF server 'call-home' protocol stack, for a single connection."; choice transport { mandatory true; description "Selects between available transports."; case ssh { if-feature "ssh-call-home"; container ssh { description "Specifies SSH-specific call-home transport configuration."; container tcp-client-parameters { description "A wrapper around the TCP client parameters to avoid name collisions."; uses tcpc:tcp-client-grouping { refine "remote-port" { default "4334"; description "The NETCONF server will attempt to connect to the IANA-assigned well-known port for 'netconf-ch-tls' (4334) if no value is specified."; } } } container ssh-server-parameters { description "A wrapper around the SSH server parameters to avoid name collisions."; uses sshs:ssh-server-grouping; } container netconf-server-parameters { description "A wrapper around the NETCONF server parameters to avoid name collisions."; uses ncs:netconf-server-grouping { refine "client-identity-mappings" { if-feature "sshcmn:ssh-x509-certs"; description "Augments in an 'if-feature' statement ensuring the 'client-identity-mappings' descendant is enabled only when SSH supports X.509 certificates."; } augment "client-identity-mappings" { description "Adds a flag indicating if a cert-to-name is required."; leaf mapping-required { type boolean; description "Indicates that the cert-to-name mapping is required (i.e., the SSH-level username is ignored)."; } } } } } } case tls { if-feature "tls-call-home"; container tls { description "Specifies TLS-specific call-home transport configuration."; container tcp-client-parameters { description "A wrapper around the TCP client parameters to avoid name collisions."; uses tcpc:tcp-client-grouping { refine "remote-port" { default "4335"; description "The NETCONF server will attempt to connect to the IANA-assigned well-known port for 'netconf-ch-tls' (4335) if no value is specified."; } } } container tls-server-parameters { description "A wrapper around the TLS server parameters to avoid name collisions."; uses tlss:tls-server-grouping { refine "client-authentication" { must 'ca-certs or ee-certs'; description "NETCONF/TLS servers MUST validate client certificates. This configures certificates at the socket-level (i.e. bags), more discriminating client-certificate checks SHOULD be implemented by the application."; reference "RFC 7589: Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication"; } } } container netconf-server-parameters { description "A wrapper around the NETCONF server parameters to avoid name collisions."; uses ncs:netconf-server-grouping { refine "client-identity-mappings/cert-to-name" { min-elements 1; description "The TLS transport requires a mapping."; } } } } } } } grouping netconf-server-app-grouping { description "A reusable grouping for configuring a NETCONF server application that supports both 'listen' and 'call-home' protocol stacks for a multiplicity of connections."; container listen { if-feature "ssh-listen or tls-listen"; presence "Indicates that server-listening ports have been configured. This statement is present so the mandatory descendant nodes do not imply that this node must be configured."; description "Configures listen behavior"; leaf idle-timeout { type uint16; units "seconds"; default "3600"; // one hour description "Specifies the maximum number of seconds that a NETCONF session may remain idle. A NETCONF session will be dropped if it is idle for an interval longer than this number of seconds. If set to zero, then the server will never drop a session because it is idle. Sessions that have a notification subscription active are never dropped."; } list endpoint { key "name"; min-elements 1; description "List of endpoints to listen for NETCONF connections."; leaf name { type string; description "An arbitrary name for the NETCONF listen endpoint."; } uses netconf-server-listen-stack-grouping; } } container call-home { if-feature "ssh-call-home or tls-call-home"; presence "Indicates that server-initiated call home connections have been configured. This statement is present so the mandatory descendant nodes do not imply that this node must be configured."; description "Configures the NETCONF server to initiate the underlying transport connection to NETCONF clients."; list netconf-client { key "name"; min-elements 1; description "List of NETCONF clients the NETCONF server is to maintain simultaneous call-home connections with."; leaf name { type string; description "An arbitrary name for the remote NETCONF client."; } container endpoints { description "Container for the list of endpoints."; list endpoint { key "name"; min-elements 1; ordered-by user; description "A non-empty user-ordered list of endpoints for this NETCONF server to try to connect to in sequence. Defining more than one enables high-availability."; leaf name { type string; description "An arbitrary name for this endpoint."; } uses netconf-server-callhome-stack-grouping; } } container connection-type { description "Indicates the NETCONF server's preference for how the NETCONF connection is maintained."; choice connection-type { mandatory true; description "Selects between available connection types."; case persistent-connection { container persistent { presence "Indicates that a persistent connection is to be maintained."; description "Maintain a persistent connection to the NETCONF client. If the connection goes down, immediately start trying to reconnect to the NETCONF client, using the reconnection strategy. This connection type minimizes any NETCONF client to NETCONF server data-transfer delay, albeit at the expense of holding resources longer."; } } case periodic-connection { container periodic { presence "Indicates that a periodic connection is to be maintained."; description "Periodically connect to the NETCONF client. This connection type increases resource utilization, albeit with increased delay in NETCONF client to NETCONF client interactions. The NETCONF client SHOULD gracefully close the connection using <close-session> upon completing planned activities. If the NETCONF session is not closed gracefully, the NETCONF server MUST immediately attempt to reestablish the connection. In the case that the previous connection is still active (i.e., the NETCONF client has not closed it yet), establishing a new connection is NOT RECOMMENDED."; leaf period { type uint16; units "minutes"; default "60"; description "Duration of time between periodic connections."; } leaf anchor-time { type yang:date-and-time { // constrained to minute-level granularity pattern '\d{4}-\d{2}-\d{2}T\d{2}:\d{2}' + '(Z|[\+\-]\d{2}:\d{2})'; } description "Designates a timestamp before or after which a series of periodic connections are determined. The periodic connections occur at a whole multiple interval from the anchor time. For example, for an anchor time is 15 minutes past midnight and a period interval of 24 hours, then a periodic connection will occur 15 minutes past midnight everyday."; } leaf idle-timeout { type uint16; units "seconds"; default "120"; // two minutes description "Specifies the maximum number of seconds that a NETCONF session may remain idle. A NETCONF session will be dropped if it is idle for an interval longer than this number of seconds. If set to zero, then the server will never drop a session because it is idle."; } } } // case periodic-connection } // choice connection-type } // container connection-type container reconnect-strategy { description "The reconnection strategy directs how a NETCONF server reconnects to a NETCONF client, after discovering its connection to the client has dropped, even if due to a reboot. The NETCONF server starts with the specified endpoint and tries to connect to it max-attempts times before trying the next endpoint in the list (round robin)."; leaf start-with { type enumeration { enum first-listed { description "Indicates that reconnections should start with the first endpoint listed."; } enum last-connected { description "Indicates that reconnections should start with the endpoint last connected to. If no previous connection has ever been established, then the first endpoint configured is used. NETCONF servers SHOULD be able to remember the last endpoint connected to across reboots."; } enum random-selection { description "Indicates that reconnections should start with a random endpoint."; } } default "first-listed"; description "Specifies which of the NETCONF client's endpoints the NETCONF server should start with when trying to connect to the NETCONF client."; } leaf max-attempts { type uint8 { range "1..max"; } default "3"; description "Specifies the number times the NETCONF server tries to connect to a specific endpoint before moving on to the next endpoint in the list (round robin)."; } } // container reconnect-strategy } // list netconf-client } // container call-home } // grouping netconf-server-app-grouping // Protocol accessible node for servers that implement this module. container netconf-server { uses netconf-server-app-grouping; description "Top-level container for NETCONF server configuration."; } }¶
<CODE ENDS>¶
4. Security Considerations
4.1. The "ietf-netconf-client" YANG Module
The "ietf-netconf-client" YANG module defines data nodes that are designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication.¶
The NETCONF access control model (NACM) [RFC8341] provides the means to restrict access for particular users to a pre-configured subset of all available protocol operations and content.¶
None of the readable data nodes defined in this YANG module are considered sensitive or vulnerable in network environments. The NACM "default-deny-all" extension has not been set for any data nodes defined in this module.¶
None of the writable data nodes defined in this YANG module are considered sensitive or vulnerable in network environments. The NACM "default-deny-write" extension has not been set for any data nodes defined in this module.¶
This module does not define any RPCs, actions, or notifications, and thus the security consideration for such is not provided here.¶
Please be aware that this module uses groupings defined in other RFCs that define data nodes that do set the NACM "default-deny-all" and "default-deny-write" extensions.¶
4.2. The "ietf-netconf-server" YANG Module
The "ietf-netconf-server" YANG module defines data nodes that are designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to-implement secure transport layers (e.g., SSH, TLS) with mutual authentication.¶
The NETCONF access control model (NACM) [RFC8341] provides the means to restrict access for particular users to a pre-configured subset of all available protocol operations and content.¶
None of the readable data nodes defined in this YANG module are considered sensitive or vulnerable in network environments. The NACM "default-deny-all" extension has not been set for any data nodes defined in this module.¶
None of the writable data nodes defined in this YANG module are considered sensitive or vulnerable in network environments. The NACM "default-deny-write" extension has not been set for any data nodes defined in this module.¶
This module does not define any RPCs, actions, or notifications, and thus the security consideration for such is not provided here.¶
Please be aware that this module uses groupings defined in other RFCs that define data nodes that do set the NACM "default-deny-all" and "default-deny-write" extensions.¶
5. IANA Considerations
5.1. The "IETF XML" Registry
This document registers two URIs in the "ns" subregistry of the IETF XML Registry [RFC3688]. Following the format in [RFC3688], the following registrations are requested:¶
URI: urn:ietf:params:xml:ns:yang:ietf-netconf-client Registrant Contact: The IESG XML: N/A, the requested URI is an XML namespace. URI: urn:ietf:params:xml:ns:yang:ietf-netconf-server Registrant Contact: The IESG XML: N/A, the requested URI is an XML namespace.¶
5.2. The "YANG Module Names" Registry
This document registers two YANG modules in the YANG Module Names registry [RFC6020]. Following the format in [RFC6020], the following registrations are requested:¶
name: ietf-netconf-client namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-client prefix: ncc reference: RFC HHHH name: ietf-netconf-server namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-server prefix: ncs reference: RFC HHHH¶
6. References
6.1. Normative References
- [I-D.ietf-netconf-keystore]
- Watsen, K., "A YANG Data Model for a Keystore", Work in Progress, Internet-Draft, draft-ietf-netconf-keystore-23, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-keystore-23>.
- [I-D.ietf-netconf-ssh-client-server]
- Watsen, K., "YANG Groupings for SSH Clients and SSH Servers", Work in Progress, Internet-Draft, draft-ietf-netconf-ssh-client-server-26, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-ssh-client-server-26>.
- [I-D.ietf-netconf-tcp-client-server]
- Watsen, K. and M. Scharf, "YANG Groupings for TCP Clients and TCP Servers", Work in Progress, Internet-Draft, draft-ietf-netconf-tcp-client-server-11, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-tcp-client-server-11>.
- [I-D.ietf-netconf-tls-client-server]
- Watsen, K., "YANG Groupings for TLS Clients and TLS Servers", Work in Progress, Internet-Draft, draft-ietf-netconf-tls-client-server-26, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-tls-client-server-26>.
- [RFC2119]
- Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
- [RFC6020]
- Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, , <https://www.rfc-editor.org/info/rfc6020>.
- [RFC6241]
- Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, , <https://www.rfc-editor.org/info/rfc6241>.
- [RFC6242]
- Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, , <https://www.rfc-editor.org/info/rfc6242>.
- [RFC6991]
- Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, , <https://www.rfc-editor.org/info/rfc6991>.
- [RFC7407]
- Bjorklund, M. and J. Schoenwaelder, "A YANG Data Model for SNMP Configuration", RFC 7407, DOI 10.17487/RFC7407, , <https://www.rfc-editor.org/info/rfc7407>.
- [RFC7589]
- Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication", RFC 7589, DOI 10.17487/RFC7589, , <https://www.rfc-editor.org/info/rfc7589>.
- [RFC7950]
- Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, , <https://www.rfc-editor.org/info/rfc7950>.
- [RFC8174]
- Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/info/rfc8174>.
6.2. Informative References
- [I-D.ietf-netconf-crypto-types]
- Watsen, K., "YANG Data Types and Groupings for Cryptography", Work in Progress, Internet-Draft, draft-ietf-netconf-crypto-types-21, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-crypto-types-21>.
- [I-D.ietf-netconf-http-client-server]
- Watsen, K., "YANG Groupings for HTTP Clients and HTTP Servers", Work in Progress, Internet-Draft, draft-ietf-netconf-http-client-server-08, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-http-client-server-08>.
- [I-D.ietf-netconf-netconf-client-server]
- Watsen, K., "NETCONF Client and Server Models", Work in Progress, Internet-Draft, draft-ietf-netconf-netconf-client-server-24, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-netconf-client-server-24>.
- [I-D.ietf-netconf-restconf-client-server]
- Watsen, K., "RESTCONF Client and Server Models", Work in Progress, Internet-Draft, draft-ietf-netconf-restconf-client-server-24, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-restconf-client-server-24>.
- [I-D.ietf-netconf-trust-anchors]
- Watsen, K., "A YANG Data Model for a Truststore", Work in Progress, Internet-Draft, draft-ietf-netconf-trust-anchors-16, , <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-trust-anchors-16>.
- [RFC3688]
- Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, , <https://www.rfc-editor.org/info/rfc3688>.
- [RFC8040]
- Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, , <https://www.rfc-editor.org/info/rfc8040>.
- [RFC8071]
- Watsen, K., "NETCONF Call Home and RESTCONF Call Home", RFC 8071, DOI 10.17487/RFC8071, , <https://www.rfc-editor.org/info/rfc8071>.
- [RFC8340]
- Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, , <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, , <https://www.rfc-editor.org/info/rfc8341>.
- [RFC8342]
- Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K., and R. Wilton, "Network Management Datastore Architecture (NMDA)", RFC 8342, DOI 10.17487/RFC8342, , <https://www.rfc-editor.org/info/rfc8342>.
Appendix A. Change Log
This section is to be removed before publishing as an RFC.¶
A.1. 00 to 01
- Renamed "keychain" to "keystore".¶
A.2. 01 to 02
A.3. 02 to 03
A.4. 03 to 04
A.5. 04 to 05
A.6. 05 to 06
A.7. 06 to 07
- Removed "idle-timeout" from "persistent" connection config.¶
- Added "random-selection" for reconnection-strategy's "starts-with" enum.¶
- Replaced "connection-type" choice default (persistent) with "mandatory true".¶
- Reduced the periodic-connection's "idle-timeout" from 5 to 2 minutes.¶
- Replaced reconnect-timeout with period/anchor-time combo.¶
A.8. 07 to 08
- Modified examples to be compatible with new crypto-types algs¶
A.9. 08 to 09
A.10. 09 to 10
- Reformatted YANG modules.¶
A.11. 10 to 11
- Adjusted for the top-level "demux container" added to groupings imported from other modules.¶
- Added "must" expressions to ensure that keepalives are not configured for "periodic" connections.¶
- Updated the boilerplate text in module-level "description" statement to match copyeditor convention.¶
- Moved "expanded" tree diagrams to the Appendix.¶
A.12. 11 to 12
- Removed the "Design Considerations" section.¶
- Removed the 'must' statement limiting keepalives in periodic connections.¶
- Updated models and examples to reflect removal of the "demux" containers in the imported models.¶
- Updated the "periodic-connnection" description statements to be more like the RESTCONF draft, especially where it described dropping the underlying TCP connection.¶
- Updated text to better reference where certain examples come from (e.g., which Section in which draft).¶
- In the server model, commented out the "must 'pinned-ca-certs or pinned-client-certs'" statement to reflect change made in the TLS draft whereby the trust anchors MAY be defined externally.¶
- Replaced the 'listen', 'initiate', and 'call-home' features with boolean expressions.¶
A.13. 12 to 13
- Updated to reflect changes in trust-anchors drafts (e.g., s/trust-anchors/truststore/g + s/pinned.//)¶
A.14. 13 to 14
A.15. 14 to 15
- Refactored both the client and server modules similar to how the ietf-restconf-server module was refactored in -13 of that draft, and the ietf-restconf-client grouping.¶
A.16. 15 to 16
A.17. 16 to 17
A.18. 17 to 18
- Updated examples to reflect new "bag" addition to truststore.¶
A.19. 18 to 19
- Updated examples to remove the 'algorithm' nodes.¶
- Updated examples to reflect the new TLS keepalives structure.¶
- Added keepalives to the tcp-client-parameters section in the netconf-server SSH-based call-home example.¶
- Added a TLS-based call-home example to the netconf-client example.¶
- Added a "Note to Reviewers" note to first page.¶
A.20. 19 to 20
A.21. 20 to 21
A.22. 21 to 22
- Addressed comments raised by YANG Doctor in the ct/ts/ks drafts.¶
A.23. 22 to 23
- Floated an 'if-feature' statement in a grouping down to where the grouping is used.¶
- Clarified 'client-identity-mappings' for both the SSH and TLS transports.¶
- For netconf-client, augmented-in a 'mapping-required' flag into 'client-identity-mappings' only for the SSH transport, and refined-in a 'min-elements 1' only for the TLS transport.¶
- Aligned modules with `pyang -f` formatting.¶
A.24. 23 to 24
A.25. 24 to 25
Acknowledgements
The authors would like to thank for following for lively discussions on list and in the halls (ordered by first name): Alan Luchuk, Andy Bierman, Balazs Kovacs, Benoit Claise, Bert Wijnen, David Lamparter, Juergen Schoenwaelder, Ladislav Lhotka, Martin Bjoerklund, Mehmet Ersue, Phil Shafer, Radek Krejci, Ramkumar Dhanapal, Sean Turner, and Tom Petch.¶