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; reference "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers"; } import ietf-ssh-server { prefix sshs; reference "RFC EEEE: YANG Groupings for SSH Clients and SSH Servers"; } import ietf-tls-server { prefix tlss; 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 Author: Kent Watsen "; description "This module contains a collection of YANG definitions for configuring NETCONF servers. Copyright (c) 2023 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 2023-04-17 { 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"; } feature central-netconf-server-supported { description "The 'central-netconf-server-supported' feature indicates that the server supports the top-level 'netconf-server' node. This feature is needed as some servers may want to use features defined in this module, which requires this module to be implemented, without having to support the top-level 'netconf-server' node."; } // 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-ssh' (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 "180"; // three 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."; } 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 decreases resource utilization, albeit with increased delay in NETCONF client to NETCONF server interactions. The NETCONF client SHOULD gracefully close the connection using upon completing planned activities. If the NETCONF session is not closed gracefully, the NETCONF server MUST immediately attempt to reestablish the connection. Connections are established at the same start time regardless how long the previous connection stayed open. 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 '[0-9]{4}-(1[0-2]|0[1-9])-(0[1-9]|[1-2]' + '[0-9]|3[0-1])T(0[0-9]|1[0-9]|2[0-3]):[' + '0-5][0-9]:00(Z|[\+\-]((1[0-3]|0[0-9]):' + '([0-5][0-9])|14:00))?'; } 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. If an 'anchor-time' is not provided, then the server may implicitly set it to the time when this configuraton is applied (e.g., on boot). 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 "180"; // three 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-wait { type uint16 { range "1..max"; } units "seconds"; default "5"; description "Specifies the amount of time in seconds after which, if the connection is not established, an endpoint connection attempt is considered unsuccessful."; } 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 { if-feature central-netconf-server-supported; uses netconf-server-app-grouping; description "Top-level container for NETCONF server configuration."; } }