RESTCONF Client and Server Models

The RESTCONF Server model presented in this section supports servers both listening for connections as well as initiating call-home connections. This model supports the TLS using the TLS server groupings defined in . All private keys and trusted certificates are held in the keychain model defined in . YANG feature statements are used to enable implementations to advertise which parts of the model the RESTCONF server supports.

Note: all lines are folded at column 71 with no '\' character.

/kc:keychain/private-keys/p rivate-key/certificate-chains/certificate-chain/name | +--rw client-auth | +--rw trusted-ca-certs? -> /kc:keychain/t rusted-certificates/name | +--rw trusted-client-certs? -> /kc:keychain/t rusted-certificates/name | +--rw cert-maps | +--rw cert-to-name* [id] | +--rw id uint32 | +--rw fingerprint x509c2n:tls-fingerpr int | +--rw map-type identityref | +--rw name string +--rw call-home {call-home}? +--rw restconf-client* [name] +--rw name string +--rw (transport) | +--:(tls) {tls-call-home}? | +--rw tls | +--rw endpoints | | +--rw endpoint* [name] | | +--rw name string | | +--rw address inet:host | | +--rw port? inet:port-number | +--rw certificates | | +--rw certificate* [name] | | +--rw name -> /kc:keychain/private-keys/p rivate-key/certificate-chains/certificate-chain/name | +--rw client-auth | +--rw trusted-ca-certs? -> /kc:keychain/t rusted-certificates/name | +--rw trusted-client-certs? -> /kc:keychain/t rusted-certificates/name | +--rw cert-maps | +--rw cert-to-name* [id] | +--rw id uint32 | +--rw fingerprint x509c2n:tls-fingerpr int | +--rw map-type identityref | +--rw name string +--rw connection-type | +--rw (connection-type)? | +--:(persistent-connection) | | +--rw persistent! | | +--rw keep-alives | | +--rw max-wait? uint16 | | +--rw max-attempts? uint8 | +--:(periodic-connection) | +--rw periodic! | +--rw reconnect-timeout? uint16 +--rw reconnect-strategy +--rw start-with? enumeration +--rw max-attempts? uint8 ]]>

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 .

netconf/tls

11.22.33.44

ex-key-sect571r1-cert

deployment-specific-ca-certs

explicitly-trusted-client-certs

1 11:0A:05:11:00

x509c2n:san-any

2 B3:4F:A1:8C:54

x509c2n:specified

scooby-doo

config-manager east-data-center

22.33.44.55

west-data-center

33.44.55.66

ex-key-sect571r1-cert

deployment-specific-ca-certs

explicitly-trusted-client-certs

1 11:0A:05:11:00

x509c2n:san-any

2 B3:4F:A1:8C:54

x509c2n:specified

scooby-doo

300

last-connected

]]>

This YANG module imports YANG types from and .

file "ietf-restconf-server@2016-07-08.yang" module ietf-restconf-server { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-restconf-server"; prefix "rcs"; //import ietf-netconf-acm { // prefix nacm; // reference // "RFC 6536: Network Configuration Protocol (NETCONF) // Access Control Model"; //} 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-tls-server { prefix ts; revision-date 2016-07-08; // stable grouping definitions reference "RFC ZZZZ: TLS Client and Server Models"; } organization "IETF NETCONF (Network Configuration) Working Group"; contact "WG Web: WG List: WG Chair: Mehmet Ersue WG Chair: Mahesh Jethanandani Editor: Kent Watsen "; description "This module contains a collection of YANG definitions for configuring RESTCONF servers. Copyright (c) 2014 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision "2016-07-08" { description "Initial version"; reference "RFC XXXX: RESTCONF Client and Server Models"; } // Features feature listen { description "The 'listen' feature indicates that the RESTCONF server supports opening a port to accept RESTCONF client connections using at least one transport (e.g., TLS, etc.)."; } feature tls-listen { description "The 'tls-listen' feature indicates that the RESTCONF server supports opening a port to listen for incoming RESTCONF client connections."; reference "RFC XXXX: RESTCONF Protocol"; } feature call-home { description "The 'call-home' feature indicates that the RESTCONF server supports initiating RESTCONF call home connections to REETCONF clients using at least one transport (e.g., TLS, etc.)."; reference "RFC YYYY: NETCONF Call Home and RESTCONF Call Home"; } feature tls-call-home { description "The 'tls-call-home' feature indicates that the RESTCONF server supports initiating connections to RESTCONF clients."; reference "RFC YYYY: NETCONF Call Home and RESTCONF Call Home"; } feature client-cert-auth { description "The client-cert-auth feature indicates that the RESTCONF server supports the ClientCertificate authentication scheme."; reference "RFC ZZZZ: Client Authentication over New TLS Connection"; } // top-level container container restconf-server { description "Top-level container for RESTCONF server configuration."; container listen { if-feature listen; description "Configures listen behavior"; leaf max-sessions { type uint16; default 0; // should this be 'max'? description "Specifies the maximum number of concurrent sessions that can be active at one time. The value 0 indicates that no artificial session limit should be used."; } list endpoint { key name; description "List of endpoints to listen for RESTCONF connections on."; leaf name { type string; description "An arbitrary name for the RESTCONF listen endpoint."; } choice transport { mandatory true; description "Selects between available transports."; case tls { if-feature tls-listen; container tls { description "TLS-specific listening configuration for inbound connections."; uses ts:listening-tls-server-grouping { refine port { default 443; } augment "client-auth" { description "Augments in the cert-to-name structure."; uses cert-maps-grouping; } } } } } } } container call-home { if-feature call-home; description "Configures call-home behavior"; list restconf-client { key name; description "List of RESTCONF clients the RESTCONF server is to initiate call-home connections to."; leaf name { type string; description "An arbitrary name for the remote RESTCONF client."; } choice transport { mandatory true; description "Selects between TLS and any transports augmented in."; case tls { if-feature tls-call-home; container tls { description "Specifies TLS-specific call-home transport configuration."; uses endpoints-container { refine endpoints/endpoint/port { default 4336; } } uses ts:non-listening-tls-server-grouping { augment "client-auth" { description "Augments in the cert-to-name structure."; uses cert-maps-grouping; } } } } } container connection-type { description "Indicates the RESTCONF client's preference for how the RESTCONF server's connection is maintained."; choice connection-type { description "Selects between available connection types."; case persistent-connection { container persistent { presence true; description "Maintain a persistent connection to the RESTCONF client. If the connection goes down, immediately start trying to reconnect to it, 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."; container keep-alives { description "Configures the keep-alive policy, to proactively test the aliveness of the TLS client. An unresponsive TLS client will be dropped after approximately (max-attempts * max-wait) seconds."; reference "RFC YYYY: NETCONF Call Home and RESTCONF Call Home, Section 3.1, item S6"; leaf max-wait { type uint16 { range "1..max"; } units seconds; default 30; description "Sets the amount of time in seconds after which if no data has been received from the TLS client, a TLS-level message will be sent to test the aliveness of the TLS client."; } leaf max-attempts { type uint8; default 3; description "Sets the maximum number of sequential keep-alive messages that can fail to obtain a response from the TLS client before assuming the TLS client is no longer alive."; } } } } case periodic-connection { container periodic { presence true; description "Periodically connect to the RESTCONF client, so that the RESTCONF client may deliver messages pending for the RESTCONF server. The client must close the connection when it's ready to release it. Once the connection has been closed, the server will restart its timer until the next connection."; leaf reconnect-timeout { type uint16 { range "1..max"; } units minutes; default 60; description "The maximum amount of unconnected time the RESTCONF server will wait before re-establishing a connection to the RESTCONF client. The RESTCONF server may initiate a connection to the RESTCONF client before this time if desired (e.g., to deliver a notification)."; } } } } } container reconnect-strategy { description "The reconnection strategy directs how a RESTCONF server reconnects to a RESTCONF client after 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."; } } 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-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)."; } } } } } grouping cert-maps-grouping { description "A grouping that defines a container around the cert-to-name structure defined in RFC 7407."; container cert-maps { uses x509c2n:cert-to-name; description "The cert-maps container is used by a TLS-based RESTCONF server to map the RESTCONF client's presented X.509 certificate to 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 XXXX: The RESTCONF Protocol"; } } grouping endpoints-container { description "This grouping is used by tls container for call-home configurations."; 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."; } leaf address { type inet:host; mandatory true; description "The IP address or hostname of the endpoint. If a hostname is configured and the DNS resolution results in more than one IP address, the RESTCONF server will process the IP addresses as if they had been explicitly configured in place of the hostname."; } leaf port { type inet:port-number; description "The IP port for this endpoint. The RESTCONF server will use the IANA-assigned well-known port if no value is specified."; } } } } }

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