Internet-Draft | RESTCONF Client and Server Models | December 2022 |
Watsen | Expires 15 June 2023 | [Page] |
This document defines two YANG modules, one module to configure a RESTCONF client and the other module to configure a RESTCONF server. Both modules support the TLS transport protocol with both standard RESTCONF and RESTCONF Call Home connections.¶
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This document defines two YANG [RFC7950] modules, one module to configure a RESTCONF client and the other module to configure a RESTCONF server [RFC8040]. Both modules support the TLS [RFC8446] transport protocol with both standard RESTCONF and RESTCONF Call Home connections [RFC8071].¶
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 both the clients and servers of both the NETCONF [RFC6241] and RESTCONF [RFC8040] protocols.¶
The normative dependency relationship between the various RFCs in this 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] |
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.¶
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>.¶
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.¶
The RESTCONF client model presented in this section supports both clients initiating connections to servers, as well as clients listening for connections from servers calling home.¶
YANG feature statements are used to enable implementations to advertise which potentially uncommon parts of the model the RESTCONF client supports.¶
This section provides an overview of the "ietf-restconf-client" module in terms of its features and groupings.¶
The following diagram lists all the "feature" statements defined in the "ietf-restconf-client" module:¶
Features: +-- https-initiate +-- http-listen +-- https-listen +-- central-restconf-client-supported¶
The diagram above uses syntax that is similar to but not defined in [RFC8340].¶
The "ietf-restconf-client" module defines the following "grouping" statements:¶
Each of these groupings are presented in the following subsections.¶
The following tree diagram [RFC8340] illustrates the "restconf-client-grouping" grouping:¶
grouping restconf-client-grouping ---> <empty>:¶
Comments:¶
The following tree diagram [RFC8340] illustrates the "restconf-client-initiate-stack-grouping" grouping:¶
grouping restconf-client-initiate-stack-grouping: +-- (transport) +--:(https) {https-initiate}? +-- https +-- tcp-client-parameters | +---u tcpc:tcp-client-grouping +-- tls-client-parameters | +---u tlsc:tls-client-grouping +-- http-client-parameters | +---u httpc:http-client-grouping +-- restconf-client-parameters +---u rcc:restconf-client-grouping¶
Comments:¶
For the referenced grouping statement(s):¶
The following tree diagram [RFC8340] illustrates the "restconf-client-listen-stack-grouping" grouping:¶
grouping restconf-client-listen-stack-grouping: +-- (transport) +--:(http) {http-listen}? | +-- http | +-- tcp-server-parameters | | +---u tcps:tcp-server-grouping | +-- http-client-parameters | | +---u httpc:http-client-grouping | +-- restconf-client-parameters | +---u rcc:restconf-client-grouping +--:(https) {https-listen}? +-- https +-- tcp-server-parameters | +---u tcps:tcp-server-grouping +-- tls-client-parameters | +---u tlsc:tls-client-grouping +-- http-client-parameters | +---u httpc:http-client-grouping +-- restconf-client-parameters +---u rcc:restconf-client-grouping¶
Comments:¶
For the referenced grouping statement(s):¶
The following tree diagram [RFC8340] illustrates the "restconf-client-app-grouping" grouping:¶
grouping restconf-client-app-grouping: +-- initiate! {https-initiate}? | +-- restconf-server* [name] | +-- name? string | +-- endpoints | | +-- endpoint* [name] | | +-- name? string | | +---u restconf-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-wait? uint16 | +-- max-attempts? uint8 +-- listen! {http-listen or https-listen}? +-- idle-timeout? uint16 +-- endpoint* [name] +-- name? string +---u restconf-client-listen-stack-grouping¶
Comments:¶
For the referenced grouping statement(s):¶
The following tree diagram [RFC8340] lists all the protocol-accessible nodes defined in the "ietf-restconf-client" module:¶
module: ietf-restconf-client +--rw restconf-client {central-restconf-client-supported}? +---u restconf-client-app-grouping¶
Comments:¶
The following example illustrates configuring a RESTCONF client to initiate connections, as well as to listen for call-home connections.¶
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 ================ <restconf-client xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf-cl\ ient"> <!-- RESTCONF servers to initiate connections to --> <initiate> <restconf-server> <name>corp-fw1</name> <endpoints> <endpoint> <name>corp-fw1.example.com</name> <https> <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> <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> <http-client-parameters> <client-identity> <basic> <user-id>bob</user-id> <cleartext-password>secret</cleartext-password> </basic> </client-identity> </http-client-parameters> </https> </endpoint> <endpoint> <name>corp-fw2.example.com</name> <https> <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> <http-client-parameters> <client-identity> <basic> <user-id>bob</user-id> <cleartext-password>secret</cleartext-password> </basic> </client-identity> </http-client-parameters> </https> </endpoint> </endpoints> <connection-type> <persistent/> </connection-type> </restconf-server> </initiate> <!-- endpoints to listen for RESTCONF Call Home connections on --> <listen> <endpoint> <name>Intranet-facing listener</name> <https> <tcp-server-parameters> <local-address>11.22.33.44</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> <http-client-parameters> <client-identity> <basic> <user-id>bob</user-id> <cleartext-password>secret</cleartext-password> </basic> </client-identity> </http-client-parameters> </https> </endpoint> </listen> </restconf-client>¶
This YANG module has normative references to [RFC6991], [RFC8040], and [RFC8071], [I-D.ietf-netconf-tcp-client-server], [I-D.ietf-netconf-tls-client-server], and [I-D.ietf-netconf-http-client-server].¶
<CODE BEGINS> file "ietf-restconf-client@2022-12-12.yang"¶
module ietf-restconf-client { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-restconf-client"; prefix rcc; 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-tls-client { prefix tlsc; reference "RFC FFFF: YANG Groupings for TLS Clients and TLS Servers"; } import ietf-http-client { prefix httpc; reference "RFC GGGG: YANG Groupings for HTTP Clients and HTTP 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>"; description "This module contains a collection of YANG definitions for configuring RESTCONF clients. Copyright (c) 2022 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 IIII (https://www.rfc-editor.org/info/rfcIIII); 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 2022-12-12 { description "Initial version"; reference "RFC IIII: RESTCONF Client and Server Models"; } // Features feature https-initiate { description "The 'https-initiate' feature indicates that the RESTCONF client supports initiating HTTPS connections to RESTCONF servers. This feature exists as HTTPS might not be a mandatory to implement transport in the future."; reference "RFC 8040: RESTCONF Protocol"; } feature http-listen { description "The 'http-listen' feature indicates that the RESTCONF client supports opening a port to listen for incoming RESTCONF server call-home connections. This feature exists as not all RESTCONF clients may support RESTCONF call home."; reference "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; } feature https-listen { description "The 'https-listen' feature indicates that the RESTCONF client supports opening a port to listen for incoming RESTCONF server call-home connections. This feature exists as not all RESTCONF clients may support RESTCONF call home."; reference "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; } feature central-restconf-client-supported { description "The 'central-restconf-client-supported' feature indicates that the server that implements this module supports the top-level 'restconf-client' 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 'restconf-client' node."; } // Groupings grouping restconf-client-grouping { description "A reusable grouping for configuring a RESTCONF client without any consideration for how underlying transport sessions are established. This grouping currently does not define any nodes. It exists only so the model can be consistent with other 'client-server' models."; } grouping restconf-client-initiate-stack-grouping { description "A reusable grouping for configuring a RESTCONF client 'initiate' protocol stack for a single connection."; choice transport { mandatory true; description "Selects between available transports. This is a 'choice' statement so as to support additional transport options to be augmented in."; case https { if-feature "https-initiate"; container https { must 'tls-client-parameters/client-identity or http-client-parameters/client-identity'; description "Specifies HTTPS-specific 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 "443"; description "The RESTCONF client will attempt to connect to the IANA-assigned well-known port value for 'https' (443) if no value is specified."; } } } container tls-client-parameters { description "A wrapper around the TLS client parameters to avoid name collisions."; uses tlsc:tls-client-grouping; } container http-client-parameters { description "A wrapper around the HTTP client parameters to avoid name collisions."; uses httpc:http-client-grouping; } container restconf-client-parameters { description "A wrapper around the RESTCONF client parameters to avoid name collisions. This container does not define any nodes. It exists as a potential augmentation target by other modules."; uses rcc:restconf-client-grouping; } } } } } // restconf-client-initiate-stack-grouping grouping restconf-client-listen-stack-grouping { description "A reusable grouping for configuring a RESTCONF 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. This is a 'choice' statement so as to support additional transport options to be augmented in."; case http { if-feature "http-listen"; container http { description "HTTP-specific listening configuration for inbound connections. This transport option is made available to support deployments where the TLS connections are terminated by another system (e.g., a load balancer) fronting the client."; 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 "4336"; description "The RESTCONF client will listen on the IANA- assigned well-known port for 'restconf-ch-tls' (4336) if no value is specified."; } } } container http-client-parameters { description "A wrapper around the HTTP client parameters to avoid name collisions."; uses httpc:http-client-grouping; } container restconf-client-parameters { description "A wrapper around the RESTCONF client parameters to avoid name collisions. This container does not define any nodes. It exists as a potential augmentation target by other modules."; uses rcc:restconf-client-grouping; } } } case https { if-feature "https-listen"; container https { must 'tls-client-parameters/client-identity or http-client-parameters/client-identity'; description "HTTPS-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 "4336"; description "The RESTCONF client will listen on the IANA- assigned well-known port for 'restconf-ch-tls' (4336) if no value is specified."; } } } container tls-client-parameters { description "A wrapper around the TLS client parameters to avoid name collisions."; uses tlsc:tls-client-grouping; } container http-client-parameters { description "A wrapper around the HTTP client parameters to avoid name collisions."; uses httpc:http-client-grouping; } container restconf-client-parameters { description "A wrapper around the RESTCONF client parameters to avoid name collisions. This container does not define any nodes. It exists as a potential augmentation target by other modules."; uses rcc:restconf-client-grouping; } } } } } // restconf-client-listen-stack-grouping grouping restconf-client-app-grouping { description "A reusable grouping for configuring a RESTCONF client application that supports both 'initiate' and 'listen' protocol stacks for a multiplicity of connections."; container initiate { if-feature "https-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 restconf-server { key "name"; min-elements 1; description "List of RESTCONF servers the RESTCONF client is to maintain simultaneous connections with."; leaf name { type string; description "An arbitrary name for the RESTCONF server."; } 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 RESTCONF client 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 restconf-client-initiate-stack-grouping; } } container connection-type { description "Indicates the RESTCONF client's preference for how the RESTCONF 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 RESTCONF server. If the connection goes down, immediately start trying to reconnect to the RESTCONF server, using the reconnection strategy. This connection type minimizes any RESTCONF server to RESTCONF 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 RESTCONF server. This connection type decreases resource utilization, albeit with increased delay in RESTCONF server to RESTCONF client interactions. The RESTCONF client SHOULD gracefully close the underlying TLS 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 the underlying TCP session may remain idle. A TCP session will be dropped if it is idle for an interval longer than this number of seconds If set to zero, then the RESTCONF client will never drop a session because it is idle."; } } } // periodic-connection } // connection-type } // connection-type container reconnect-strategy { description "The reconnection strategy directs how a RESTCONF client reconnects to a RESTCONF server, after discovering its connection to the server has dropped, even if due to a reboot. The RESTCONF 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. RESTCONF 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 RESTCONF server's endpoints the RESTCONF client should start with when trying to connect to the RESTCONF server."; } 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 RESTCONF client tries to connect to a specific endpoint before moving on to the next endpoint in the list (round robin)."; } } } } // initiate container listen { if-feature "http-listen or https-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 an underlying TCP session may remain idle. A TCP session will be dropped if it is idle for an interval longer then 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 RESTCONF connections."; leaf name { type string; description "An arbitrary name for the RESTCONF listen endpoint."; } uses restconf-client-listen-stack-grouping; } } } // restconf-client-app-grouping // Protocol accessible node for servers that implement this module. container restconf-client { if-feature central-restconf-client-supported; uses restconf-client-app-grouping; description "Top-level container for RESTCONF client configuration."; } }¶
<CODE ENDS>¶
The RESTCONF server model presented in this section supports both listening for connections as well as initiating call-home connections.¶
YANG feature statements are used to enable implementations to advertise which potentially uncommon parts of the model the RESTCONF server supports.¶
This section provides an overview of the "ietf-restconf-server" module in terms of its features and groupings.¶
The following diagram lists all the "feature" statements defined in the "ietf-restconf-server" module:¶
Features: +-- http-listen +-- https-listen +-- https-call-home +-- central-restconf-server-supported¶
The diagram above uses syntax that is similar to but not defined in [RFC8340].¶
The "ietf-restconf-server" module defines the following "grouping" statements:¶
Each of these groupings are presented in the following subsections.¶
The following tree diagram [RFC8340] illustrates the "restconf-server-grouping" grouping:¶
grouping restconf-server-grouping: +-- client-identity-mappings +---u x509c2n:cert-to-name¶
Comments:¶
For the referenced grouping statement(s):¶
The following tree diagram [RFC8340] illustrates the "restconf-server-listen-stack-grouping" grouping:¶
grouping restconf-server-listen-stack-grouping: +-- (transport) +--:(http) {http-listen}? | +-- http | +-- external-endpoint! | | +-- address inet:ip-address | | +-- port? inet:port-number | +-- tcp-server-parameters | | +---u tcps:tcp-server-grouping | +-- http-server-parameters | | +---u https:http-server-grouping | +-- restconf-server-parameters | +---u rcs:restconf-server-grouping +--:(https) {https-listen}? +-- https +-- tcp-server-parameters | +---u tcps:tcp-server-grouping +-- tls-server-parameters | +---u tlss:tls-server-grouping +-- http-server-parameters | +---u https:http-server-grouping +-- restconf-server-parameters +---u rcs:restconf-server-grouping¶
Comments:¶
For the referenced grouping statement(s):¶
The following tree diagram [RFC8340] illustrates the "restconf-server-callhome-stack-grouping" grouping:¶
grouping restconf-server-callhome-stack-grouping: +-- (transport) +--:(https) {https-listen}? +-- https +-- tcp-client-parameters | +---u tcpc:tcp-client-grouping +-- tls-server-parameters | +---u tlss:tls-server-grouping +-- http-server-parameters | +---u https:http-server-grouping +-- restconf-server-parameters +---u rcs:restconf-server-grouping¶
Comments:¶
For the referenced grouping statement(s):¶
The following tree diagram [RFC8340] illustrates the "restconf-server-app-grouping" grouping:¶
grouping restconf-server-app-grouping: +-- listen! {http-listen or https-listen}? | +-- endpoint* [name] | +-- name? string | +---u restconf-server-listen-stack-grouping +-- call-home! {https-call-home}? +-- restconf-client* [name] +-- name? string +-- endpoints | +-- endpoint* [name] | +-- name? string | +---u restconf-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-wait? uint16 +-- max-attempts? uint8¶
Comments:¶
For the referenced grouping statement(s):¶
The following tree diagram [RFC8340] lists all the protocol-accessible nodes defined in the "ietf-restconf-server" module:¶
module: ietf-restconf-server +--rw restconf-server {central-restconf-server-supported}? +---u restconf-server-app-grouping¶
Comments:¶
The following example illustrates configuring a RESTCONF server to listen for RESTCONF client connections, as well as configuring call-home to one RESTCONF client.¶
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 ================ <restconf-server xmlns="urn:ietf:params:xml:ns:yang:ietf-restconf-server" xmlns:x509c2n="urn:ietf:params:xml:ns:yang:ietf-x509-cert-to-name"> <!-- endpoints to listen for RESTCONF connections on --> <listen> <endpoint> <name>restconf/https</name> <https> <tcp-server-parameters> <local-address>11.22.33.44</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> <http-server-parameters> <server-name>foo.example.com</server-name> </http-server-parameters> <restconf-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> </restconf-server-parameters> </https> </endpoint> </listen> <!-- call home to a RESTCONF client with two endpoints --> <call-home> <restconf-client> <name>config-manager</name> <endpoints> <endpoint> <name>east-data-center</name> <https> <tcp-client-parameters> <remote-address>east.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-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> <http-server-parameters> <server-name>foo.example.com</server-name> </http-server-parameters> <restconf-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> </restconf-server-parameters> </https> </endpoint> <endpoint> <name>west-data-center</name> <https> <tcp-client-parameters> <remote-address>west.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-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> <http-server-parameters> <server-name>foo.example.com</server-name> </http-server-parameters> <restconf-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> </restconf-server-parameters> </https> </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-wait>3</max-wait> <max-attempts>3</max-attempts> </reconnect-strategy> </restconf-client> </call-home> </restconf-server>¶
This YANG module has normative references to [RFC6991], [RFC7407], [RFC8040], [RFC8071], [I-D.ietf-netconf-tcp-client-server], [I-D.ietf-netconf-tls-client-server], and [I-D.ietf-netconf-http-client-server].¶
<CODE BEGINS> file "ietf-restconf-server@2022-12-12.yang"¶
module ietf-restconf-server { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-restconf-server"; prefix rcs; import ietf-yang-types { prefix yang; reference "RFC 6991: Common YANG Data Types"; } import ietf-inet-types { prefix inet; 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-tls-server { prefix tlss; reference "RFC FFFF: YANG Groupings for TLS Clients and TLS Servers"; } import ietf-http-server { prefix https; reference "RFC GGGG: YANG Groupings for HTTP Clients and HTTP 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>"; description "This module contains a collection of YANG definitions for configuring RESTCONF servers. Copyright (c) 2022 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 IIII (https://www.rfc-editor.org/info/rfcIIII); 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 2022-12-12 { description "Initial version"; reference "RFC IIII: RESTCONF Client and Server Models"; } // Features feature http-listen { description "The 'http-listen' feature indicates that the RESTCONF server supports opening a port to listen for incoming RESTCONF over TPC client connections, whereby the TLS connections are terminated by an external system."; reference "RFC 8040: RESTCONF Protocol"; } feature https-listen { description "The 'https-listen' feature indicates that the RESTCONF server supports opening a port to listen for incoming RESTCONF over TLS client connections, whereby the TLS connections are terminated by the server itself."; reference "RFC 8040: RESTCONF Protocol"; } feature https-call-home { description "The 'https-call-home' feature indicates that the RESTCONF server supports initiating connections to RESTCONF clients."; reference "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; } feature central-restconf-server-supported { description "The 'central-restconf-server-supported' feature indicates that the server supports the top-level 'restconf-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 'restconf-server' node."; } // Groupings grouping restconf-server-grouping { description "A reusable grouping for configuring a RESTCONF 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., 'restconf-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 RESTCONF client X.509 certificates are used to determine a RESTCONF username. If no matching and valid cert-to-name list entry can be found, then the RESTCONF server MUST close the connection, and MUST NOT accept RESTCONF messages over it."; reference "RFC 7407: A YANG Data Model for SNMP Configuration."; 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 restconf-server-listen-stack-grouping { description "A reusable grouping for configuring a RESTCONF server 'listen' protocol stack for a single connection."; choice transport { mandatory true; description "Selects between available transports. This is a 'choice' statement so as to support additional transport options to be augmented in."; case http { if-feature "http-listen"; container http { description "Configures RESTCONF server stack assuming that TLS-termination is handled externally."; container external-endpoint { presence "Identifies that an external endpoint has been configured. This statement is present so the mandatory descendant nodes do not imply that this node must be configured."; description "Identifies contact information for the external system that terminates connections before passing them thru to this server (e.g., a network address translator or a load balancer). These values have no effect on the local operation of this server, but may be used by the application when needing to inform other systems how to contact this server."; leaf address { type inet:ip-address; mandatory true; description "The IP address or hostname of the external system that terminates incoming RESTCONF client connections before forwarding them to this server."; } leaf port { type inet:port-number; default "443"; description "The port number that the external system listens on for incoming RESTCONF client connections that are forwarded to this server. The default HTTPS port (443) is used, as expected for a RESTCONF connection."; } } 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 "80"; description "The RESTCONF server will listen on the IANA- assigned well-known port value for 'http' (80) if no value is specified."; } } } container http-server-parameters { description "A wrapper around the HTTP server parameters to avoid name collisions."; uses https:http-server-grouping; } container restconf-server-parameters { description "A wrapper around the RESTCONF server parameters to avoid name collisions."; uses rcs:restconf-server-grouping; } } } case https { if-feature "https-listen"; container https { description "Configures RESTCONF server stack assuming that TLS-termination is handled internally."; 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 "443"; description "The RESTCONF server will listen on the IANA- assigned well-known port value for 'https' (443) 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; } container http-server-parameters { description "A wrapper around the HTTP server parameters to avoid name collisions."; uses https:http-server-grouping; } container restconf-server-parameters { description "A wrapper around the RESTCONF server parameters to avoid name collisions."; uses rcs:restconf-server-grouping; } } } } } grouping restconf-server-callhome-stack-grouping { description "A reusable grouping for configuring a RESTCONF server 'call-home' protocol stack, for a single connection."; choice transport { mandatory true; description "Selects between available transports. This is a 'choice' statement so as to support additional transport options to be augmented in."; case https { if-feature "https-listen"; container https { description "Configures RESTCONF server stack assuming that TLS-termination is handled internally."; 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 "4336"; description "The RESTCONF server will attempt to connect to the IANA-assigned well-known port for 'restconf-ch-tls' (4336) 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; } container http-server-parameters { description "A wrapper around the HTTP server parameters to avoid name collisions."; uses https:http-server-grouping; } container restconf-server-parameters { description "A wrapper around the RESTCONF server parameters to avoid name collisions."; uses rcs:restconf-server-grouping; } } } } } grouping restconf-server-app-grouping { description "A reusable grouping for configuring a RESTCONF server application that supports both 'listen' and 'call-home' protocol stacks for a multiplicity of connections."; container listen { if-feature "http-listen or https-listen"; presence "Identifies that the server has been configured to listen for incoming client connections. This statement is present so the mandatory descendant nodes do not imply that this node must be configured."; description "Configures the RESTCONF server to listen for RESTCONF client connections."; list endpoint { key "name"; min-elements 1; description "List of endpoints to listen for RESTCONF connections."; leaf name { type string; description "An arbitrary name for the RESTCONF listen endpoint."; } uses restconf-server-listen-stack-grouping; } } container call-home { if-feature "https-call-home"; presence "Identifies that the server has been configured to initiate call home connections. This statement is present so the mandatory descendant nodes do not imply that this node must be configured."; description "Configures the RESTCONF server to initiate the underlying transport connection to RESTCONF clients."; list restconf-client { key "name"; min-elements 1; description "List of RESTCONF clients the RESTCONF server is to maintain simultaneous call-home connections with."; leaf name { type string; description "An arbitrary name for the remote RESTCONF client."; } container endpoints { description "Container for the list of endpoints."; list endpoint { key "name"; min-elements 1; ordered-by user; description "User-ordered list of endpoints for this RESTCONF client. Defining more than one enables high- availability."; leaf name { type string; description "An arbitrary name for this endpoint."; } uses restconf-server-callhome-stack-grouping; } } container connection-type { description "Indicates the RESTCONF server's preference for how the RESTCONF 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 RESTCONF client. If the connection goes down, immediately start trying to reconnect to the RESTCONF client, using the reconnection strategy. This connection type minimizes any RESTCONF client to RESTCONF 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 RESTCONF client. This connection type decreases resource utilization, albeit with increased delay in RESTCONF client to RESTCONF client interactions. The RESTCONF client SHOULD gracefully close the underlying TLS connection upon completing planned activities. If the underlying TLS connection is not closed gracefully, the RESTCONF server MUST immediately attempt to reestablish the connection. In the case that the previous connection is still active (i.e., the RESTCONF 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 the underlying TCP session may remain idle. A TCP 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."; } } } } } container reconnect-strategy { description "The reconnection strategy directs how a RESTCONF server reconnects to a RESTCONF client after discovering its connection to the client has dropped, even if due to a reboot. The RESTCONF 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. RESTCONF 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 RESTCONF client's endpoints the RESTCONF server should start with when trying to connect to the RESTCONF 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 RESTCONF server tries to connect to a specific endpoint before moving on to the next endpoint in the list (round robin)."; } } } // restconf-client } // call-home } // restconf-server-app-grouping // Protocol accessible node for servers that implement this module. container restconf-server { if-feature central-restconf-server-supported; uses restconf-server-app-grouping; description "Top-level container for RESTCONF server configuration."; } }¶
<CODE ENDS>¶
The "ietf-restconf-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 Network 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 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 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.¶
The "ietf-restconf-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 Network 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 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 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.¶
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-restconf-client Registrant Contact: The IESG XML: N/A, the requested URI is an XML namespace. URI: urn:ietf:params:xml:ns:yang:ietf-restconf-server Registrant Contact: The IESG XML: N/A, the requested URI is an XML namespace.¶
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-restconf-client namespace: urn:ietf:params:xml:ns:yang:ietf-restconf-client prefix: rcc reference: RFC IIII name: ietf-restconf-server namespace: urn:ietf:params:xml:ns:yang:ietf-restconf-server prefix: rcs reference: RFC IIII¶
This section is to be removed before publishing as an RFC.¶
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, Michal Vasko, Phil Shafer, Qiufang Ma, Radek Krejci, Ramkumar Dhanapal, Sean Turner, and Tom Petch.¶