NETCONF Working Group K. Watsen Internet-Draft Juniper Networks Intended status: Standards Track G. Wu Expires: December 6, 2018 Cisco Networks June 4, 2018 RESTCONF Client and Server Models draft-ietf-netconf-restconf-client-server-06 Abstract 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. Editorial Note (To be removed by RFC Editor) This draft contains many 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. This document contains references to other drafts in progress, both in the Normative References section, as well as in body text throughout. Please update the following references to reflect their final RFC assignments: o I-D.ietf-netconf-keystore o I-D.ietf-netconf-tls-client-server Artwork in this document contains shorthand references to drafts in progress. Please apply the following replacements: o "XXXX" --> the assigned RFC value for this draft o "ZZZZ" --> the assigned RFC value for I-D.ietf-netconf-tls-client- server Artwork in this document contains placeholder values for the date of publication of this draft. Please apply the following replacement: o "2018-06-04" --> the publication date of this draft The following Appendix section is to be removed prior to publication: Watsen & Wu Expires December 6, 2018 [Page 1] Internet-Draft RESTCONF Client and Server Models June 2018 o 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 December 6, 2018. Copyright Notice Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 2. The RESTCONF Client Model . . . . . . . . . . . . . . . . . . 3 2.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 6 2.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 8 3. The RESTCONF Server Model . . . . . . . . . . . . . . . . . . 17 3.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 17 3.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 20 3.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 23 4. Security Considerations . . . . . . . . . . . . . . . . . . . 32 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33 Watsen & Wu Expires December 6, 2018 [Page 2] Internet-Draft RESTCONF Client and Server Models June 2018 5.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 33 5.2. The YANG Module Names Registry . . . . . . . . . . . . . 34 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 34 6.1. Normative References . . . . . . . . . . . . . . . . . . 34 6.2. Informative References . . . . . . . . . . . . . . . . . 35 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 37 A.1. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . 37 A.2. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . 37 A.3. 02 to 03 . . . . . . . . . . . . . . . . . . . . . . . . 37 A.4. 03 to 04 . . . . . . . . . . . . . . . . . . . . . . . . 37 A.5. 04 to 05 . . . . . . . . . . . . . . . . . . . . . . . . 37 A.6. 05 to 06 . . . . . . . . . . . . . . . . . . . . . . . . 38 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 38 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 38 1. Introduction 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 [RFC5246] transport protocol with both standard RESTCONF and RESTCONF Call Home connections [RFC8071]. 1.1. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 2. The RESTCONF Client Model 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. This model, like that presented in [I-D.ietf-netconf-netconf-client-server], is designed to support any number of possible transports. RESTCONF only supports the TLS transport currently, thus this model only supports the TLS transport. All private keys and trusted certificates are held in the keystore model defined in [I-D.ietf-netconf-keystore]. YANG feature statements are used to enable implementations to advertise which parts of the model the RESTCONF client supports. Watsen & Wu Expires December 6, 2018 [Page 3] Internet-Draft RESTCONF Client and Server Models June 2018 2.1. Tree Diagram The following tree diagram [RFC8340] provides an overview of the data model for the "ietf-restconf-client" module. Just the container is displayed below, but there is also a reuable grouping by the same name that the container is using. [Note: '\' line wrapping for formatting only] module: ietf-restconf-client +--rw restconf-client +--rw initiate! {initiate}? | +--rw restconf-server* [name] | +--rw name string | +--rw endpoints | +--rw endpoint* [name] | +--rw name string | +--rw (transport) | | +--:(tls) {tls-initiate}? | | +--rw tls | | +--rw address inet:host | | +--rw port? inet:port-number | | +--rw client-identity | | | +--rw (auth-type) | | | +--:(certificate) | | | +--rw certificate | | | +--rw (local-or-keystore) | | | +--:(local) | | | | +--rw algorithm | | | | | ct:key-algorithm\ -ref | | | | +--rw public-key | | | | | binary | | | | +--rw private-key | | | | | union | | | | +--rw cert | | | | | ct:end-entity-ce\ rt-cms | | | | +---n certificate-expira\ tion | | | | +-- expiration-date? | | | | yang:date-and\ -time | | | +--:(keystore) | | | {keystore-implemen\ ted}? | | | +--rw reference Watsen & Wu Expires December 6, 2018 [Page 4] Internet-Draft RESTCONF Client and Server Models June 2018 | | | ks:asymmetric-ke\ y-certificate-ref | | +--rw server-auth | | | +--rw pinned-ca-certs? | | | | ta:pinned-certificates-ref | | | +--rw pinned-server-certs? | | | ta:pinned-certificates-ref | | +--rw hello-params | | {tls-client-hello-params-config}? | | +--rw tls-versions | | | +--rw tls-version* identityref | | +--rw cipher-suites | | +--rw cipher-suite* identityref | +--rw connection-type | | +--rw (connection-type)? | | +--:(persistent-connection) | | | +--rw persistent! | | | +--rw idle-timeout? uint32 | | | +--rw keep-alives | | | +--rw max-wait? uint16 | | | +--rw max-attempts? uint8 | | +--:(periodic-connection) | | +--rw periodic! | | +--rw idle-timeout? uint16 | | +--rw reconnect-timeout? uint16 | +--rw reconnect-strategy | +--rw start-with? enumeration | +--rw max-attempts? uint8 +--rw listen! {listen}? +--rw idle-timeout? uint16 +--rw endpoint* [name] +--rw name string +--rw (transport) +--:(tls) {tls-listen}? +--rw tls +--rw address? inet:ip-address +--rw port? inet:port-number +--rw client-identity | +--rw (auth-type) | +--:(certificate) | +--rw certificate | +--rw (local-or-keystore) | +--:(local) | | +--rw algorithm | | | ct:key-algorithm-ref | | +--rw public-key | | | binary | | +--rw private-key Watsen & Wu Expires December 6, 2018 [Page 5] Internet-Draft RESTCONF Client and Server Models June 2018 | | | union | | +--rw cert | | | ct:end-entity-cert-cms\ | | +---n certificate-expiration | | +-- expiration-date? | | yang:date-and-time | +--:(keystore) | {keystore-implemented}? | +--rw reference | ks:asymmetric-key-cert\ ificate-ref +--rw server-auth | +--rw pinned-ca-certs? | | ta:pinned-certificates-ref | +--rw pinned-server-certs? | ta:pinned-certificates-ref +--rw hello-params {tls-client-hello-params-config}? +--rw tls-versions | +--rw tls-version* identityref +--rw cipher-suites +--rw cipher-suite* identityref 2.2. Example Usage The following example illustrates configuring a RESTCONF client to initiate connections, as well as listening for call-home connections. This example is consistent with the examples presented in Section 2.2 of [I-D.ietf-netconf-keystore]. [Note: '\' line wrapping for formatting only] corp-fw1 corp-fw1.example.com
corp-fw1.example.com
Watsen & Wu Expires December 6, 2018 [Page 6] Internet-Draft RESTCONF Client and Server Models June 2018 ct:secp521r1 base64encodedvalue== base64encodedvalue== base64encodedvalue== explicitly-trusted-server-ca-certs<\ /pinned-ca-certs> explicitly-trusted-server-certs\ corp-fw2.example.com
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ct:secp521r1 base64encodedvalue== base64encodedvalue== base64encodedvalue== explicitly-trusted-server-ca-certs<\ /pinned-ca-certs> explicitly-trusted-server-certs\ \ Intranet-facing listener
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YANG Module This YANG module has normative references to [RFC6991], [RFC8040], and [RFC8071], and [I-D.ietf-netconf-tls-client-server]. file "ietf-restconf-client@2018-06-04.yang" module ietf-restconf-client { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-restconf-client"; prefix "rcc"; import ietf-inet-types { prefix inet; reference "RFC 6991: Common YANG Data Types"; } import ietf-tls-client { prefix ts; revision-date 2018-06-04; // stable grouping definitions reference "RFC ZZZZ: YANG Groupings for TLS Clients and TLS Servers"; } organization "IETF NETCONF (Network Configuration) Working Group"; Watsen & Wu Expires December 6, 2018 [Page 8] Internet-Draft RESTCONF Client and Server Models June 2018 contact "WG Web: WG List: Author: Kent Watsen Author: Gary Wu "; description "This module contains a collection of YANG definitions for configuring RESTCONF clients. Copyright (c) 2017 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 "2018-06-04" { description "Initial version"; reference "RFC XXXX: RESTCONF Client and Server Models"; } // Features feature initiate { description "The 'initiate' feature indicates that the RESTCONF client supports initiating RESTCONF connections to RESTCONF servers using at least one transport (e.g., TLS, etc.)."; } feature tls-initiate { if-feature initiate; description "The 'tls-initiate' feature indicates that the RESTCONF client Watsen & Wu Expires December 6, 2018 [Page 9] Internet-Draft RESTCONF Client and Server Models June 2018 supports initiating TLS connections to RESTCONF servers. This feature exists as TLS might not be a mandatory to implement transport in the future."; reference "RFC 8040: RESTCONF Protocol"; } feature listen { description "The 'listen' feature indicates that the RESTCONF client supports opening a port to accept RESTCONF server call home connections using at least one transport (e.g., TLS, etc.)."; } feature tls-listen { if-feature listen; description "The 'tls-listen' feature indicates that the RESTCONF client supports opening a port to listen for incoming RESTCONF server call-home TLS connections. This feature exists as TLS might not be a mandatory to implement transport in the future."; reference "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; } container restconf-client { uses restconf-client; description "Top-level container for RESTCONF client configuration."; } grouping restconf-client { description "Top-level grouping for RESTCONF client configuration."; container initiate { if-feature initiate; presence "Enables client to initiate TCP connections"; 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 initiate connections to in parallel."; Watsen & Wu Expires December 6, 2018 [Page 10] Internet-Draft RESTCONF Client and Server Models June 2018 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."; } 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 tls { if-feature tls-initiate; container tls { description "Specifies TLS-specific transport configuration."; leaf address { type inet:host; mandatory true; description "The IP address or hostname of the endpoint. If a domain name is configured, then the DNS resolution should happen on each usage attempt. If the the DNS resolution results in multiple IP addresses, the IP addresses will be tried according to local preference order until a connection has been established or until all IP addresses have failed."; } leaf port { type inet:port-number; Watsen & Wu Expires December 6, 2018 [Page 11] Internet-Draft RESTCONF Client and Server Models June 2018 default 443; description "The IP port for this endpoint. The RESTCONF client will use the IANA-assigned well-known port for 'https' (443) if no value is specified."; } uses ts:tls-client-grouping { refine "client-identity/auth-type" { mandatory true; description "RESTCONF clients MUST pass some authentication credentials."; } } } } // end tls } // end transport container connection-type { description "Indicates the kind of connection to use."; choice connection-type { default persistent-connection; 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 it, 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."; leaf idle-timeout { type uint32; units "seconds"; default 86400; // one day; description "Specifies the maximum number of seconds that the underlying TLS session may remain idle. A TLS session will be dropped if it is idle for an interval longer than this number of seconds. If set to zero, then Watsen & Wu Expires December 6, 2018 [Page 12] Internet-Draft RESTCONF Client and Server Models June 2018 the client will never drop a session because it is idle. Sessions that have a notification subscription active are never dropped."; } container keep-alives { description "Configures the keep-alive policy, to proactively test the aliveness of the TLS server. An unresponsive TLS server will be dropped after approximately max-attempts * max-wait seconds."; reference "RFC 8071: 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 server, a TLS-level message will be sent to test the aliveness of the TLS server."; } 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 server before assuming the TLS server is no longer alive."; } } } } case periodic-connection { container periodic { presence "Indicates that a periodic connection is to be maintained."; description "Periodically connect to the RESTCONF server, Watsen & Wu Expires December 6, 2018 [Page 13] Internet-Draft RESTCONF Client and Server Models June 2018 so that, e.g., the RESTCONF client can collect data (logs) from the RESTCONF server. Once the connection is closed, for whatever reason, the RESTCONF client will restart its timer until the next connection."; leaf idle-timeout { type uint16; units "seconds"; default 300; // five minutes description "Specifies the maximum number of seconds that the underlying TLS session may remain idle. A TLS 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."; } leaf reconnect-timeout { type uint16 { range "1..max"; } units minutes; default 60; description "Sets the maximum amount of unconnected time the RESTCONF client will wait before re- establishing a connection to the RESTCONF server. The RESTCONF client may initiate a connection before this time if desired (e.g., to set configuration)."; } } } // end periodic-connection } // end connection-type } // end 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 { Watsen & Wu Expires December 6, 2018 [Page 14] Internet-Draft RESTCONF Client and Server Models June 2018 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."; } } 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-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)."; } } // end reconnect-strategy } // end endpoint } // end endpoints } // end restconf-server } // end initiate container listen { if-feature listen; presence "Enables client to accept call-home connections"; description "Configures client accepting call-home TCP connections."; leaf idle-timeout { type uint16; Watsen & Wu Expires December 6, 2018 [Page 15] Internet-Draft RESTCONF Client and Server Models June 2018 units "seconds"; default 3600; // one hour description "Specifies the maximum number of seconds that an underlying TLS session may remain idle. A TLS 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 RESTCONF connections."; leaf name { type string; description "An arbitrary name for the RESTCONF listen endpoint."; } 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 tls { if-feature tls-listen; container tls { description "TLS-specific listening configuration for inbound connections."; leaf address { type inet:ip-address; description "The IP address to listen on for incoming call- home connections. The RESTCONF client will listen on all configured interfaces if no value is specified. INADDR_ANY (0.0.0.0) or INADDR6_ANY (0:0:0:0:0:0:0:0 a.k.a. ::) MUST be used when the server is to listen on all IPv4 or IPv6 addresses, respectively."; } leaf port { type inet:port-number; default 4336; Watsen & Wu Expires December 6, 2018 [Page 16] Internet-Draft RESTCONF Client and Server Models June 2018 description "The port number to listen on for call-home connections. The RESTCONF client will listen on the IANA-assigned well-known port for 'restconf-ch-tls' (4336) if no value is specified."; } uses ts:tls-client-grouping { refine "client-identity/auth-type" { mandatory true; description "RESTCONF clients MUST pass some authentication credentials."; } } } } } // end transport } // end endpoint } // end listen } // end restconf-client } 3. The RESTCONF Server Model The RESTCONF server model presented in this section supports servers both listening for connections as well as initiating call-home connections. All private keys and trusted certificates are held in the keystore model defined in [I-D.ietf-netconf-keystore]. YANG feature statements are used to enable implementations to advertise which parts of the model the RESTCONF server supports. 3.1. Tree Diagram The following tree diagram [RFC8340] provides an overview of the data model for the "ietf-restconf-client" module. Just the container is displayed below, but there is also a reuable grouping by the same name that the container is using. [Note: '\' line wrapping for formatting only] module: ietf-restconf-server +--rw restconf-server Watsen & Wu Expires December 6, 2018 [Page 17] Internet-Draft RESTCONF Client and Server Models June 2018 +--rw listen! {listen}? | +--rw endpoint* [name] | +--rw name string | +--rw (transport) | +--:(tls) {tls-listen}? | +--rw tls | +--rw address? inet:ip-address | +--rw port? inet:port-number | +--rw server-identity | | +--rw (local-or-keystore) | | +--:(local) | | | +--rw algorithm | | | | ct:key-algorithm-ref | | | +--rw public-key binary | | | +--rw private-key union | | | +--rw cert | | | | ct:end-entity-cert-cms | | | +---n certificate-expiration | | | +-- expiration-date? | | | yang:date-and-time | | +--:(keystore) {keystore-implemented}? | | +--rw reference | | ks:asymmetric-key-certificate-r\ ef | +--rw client-auth | | +--rw pinned-ca-certs? | | | ta:pinned-certificates-ref | | +--rw pinned-client-certs? | | | ta:pinned-certificates-ref | | +--rw cert-maps | | +--rw cert-to-name* [id] | | +--rw id uint32 | | +--rw fingerprint | | | x509c2n:tls-fingerprint | | +--rw map-type identityref | | +--rw name string | +--rw hello-params | {tls-server-hello-params-config}? | +--rw tls-versions | | +--rw tls-version* identityref | +--rw cipher-suites | +--rw cipher-suite* identityref +--rw call-home! {call-home}? +--rw restconf-client* [name] +--rw name string +--rw endpoints | +--rw endpoint* [name] | +--rw name string Watsen & Wu Expires December 6, 2018 [Page 18] Internet-Draft RESTCONF Client and Server Models June 2018 | +--rw (transport) | +--:(tls) {tls-call-home}? | +--rw tls | +--rw address inet:host | +--rw port? inet:port-number | +--rw server-identity | | +--rw (local-or-keystore) | | +--:(local) | | | +--rw algorithm | | | | ct:key-algorithm-ref | | | +--rw public-key | | | | binary | | | +--rw private-key | | | | union | | | +--rw cert | | | | ct:end-entity-cert-cms | | | +---n certificate-expiration | | | +-- expiration-date? | | | yang:date-and-time | | +--:(keystore) {keystore-implemented\ }? | | +--rw reference | | ks:asymmetric-key-certifi\ cate-ref | +--rw client-auth | | +--rw pinned-ca-certs? | | | ta:pinned-certificates-ref | | +--rw pinned-client-certs? | | | ta:pinned-certificates-ref | | +--rw cert-maps | | +--rw cert-to-name* [id] | | +--rw id uint32 | | +--rw fingerprint | | | x509c2n:tls-fingerprint | | +--rw map-type identityref | | +--rw name string | +--rw hello-params | {tls-server-hello-params-config}? | +--rw tls-versions | | +--rw tls-version* identityref | +--rw cipher-suites | +--rw cipher-suite* identityref +--rw connection-type | +--rw (connection-type)? | +--:(persistent-connection) | | +--rw persistent! | | +--rw idle-timeout? uint32 | | +--rw keep-alives Watsen & Wu Expires December 6, 2018 [Page 19] Internet-Draft RESTCONF Client and Server Models June 2018 | | +--rw max-wait? uint16 | | +--rw max-attempts? uint8 | +--:(periodic-connection) | +--rw periodic! | +--rw idle-timeout? uint16 | +--rw reconnect-timeout? uint16 +--rw reconnect-strategy +--rw start-with? enumeration +--rw max-attempts? uint8 3.2. Example Usage 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-keystore]. [Note: '\' line wrapping for formatting only] netconf/tls
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ct:secp521r1 base64encodedvalue== base64encodedvalue== base64encodedvalue== explicitly-trusted-client-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 60 last-connected 3 Watsen & Wu Expires December 6, 2018 [Page 22] Internet-Draft RESTCONF Client and Server Models June 2018 3.3. YANG Module This YANG module has normative references to [RFC6991], [RFC7407], [RFC8040], [RFC8071], and [I-D.ietf-netconf-tls-client-server]. file "ietf-restconf-server@2018-06-04.yang" module ietf-restconf-server { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-restconf-server"; prefix "rcs"; 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 2018-06-04; // stable grouping definitions reference "RFC ZZZZ: YANG Groupings for TLS Clients and TLS Servers"; } organization "IETF NETCONF (Network Configuration) Working Group"; contact "WG Web: WG List: Author: Kent Watsen Author: Gary Wu Watsen & Wu Expires December 6, 2018 [Page 23] Internet-Draft RESTCONF Client and Server Models June 2018 Author: Juergen Schoenwaelder "; description "This module contains a collection of YANG definitions for configuring RESTCONF servers. Copyright (c) 2017 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 "2018-06-04" { 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 { if-feature listen; description "The 'tls-listen' feature indicates that the RESTCONF server supports opening a port to listen for incoming RESTCONF client connections. This feature exists as TLS might not be a mandatory to implement transport in the future."; reference "RFC 8040: RESTCONF Protocol"; } Watsen & Wu Expires December 6, 2018 [Page 24] Internet-Draft RESTCONF Client and Server Models June 2018 feature call-home { description "The 'call-home' feature indicates that the RESTCONF server supports initiating RESTCONF call home connections to RESTCONF clients using at least one transport (e.g., TLS, etc.)."; reference "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; } feature tls-call-home { if-feature call-home; description "The 'tls-call-home' feature indicates that the RESTCONF server supports initiating connections to RESTCONF clients. This feature exists as TLS might not be a mandatory to implement transport in the future."; reference "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; } container restconf-server { uses restconf-server; description "Top-level container for RESTCONF server configuration."; } grouping restconf-server { description "Top-level grouping for RESTCONF server configuration."; container listen { if-feature listen; presence "Enables server to listen for TCP connections"; description "Configures listen behavior"; 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."; } choice transport { mandatory true; description Watsen & Wu Expires December 6, 2018 [Page 25] Internet-Draft RESTCONF Client and Server Models June 2018 "Selects between available transports. This is a 'choice' statement so as to support additional transport options to be augmented in."; case tls { if-feature tls-listen; container tls { description "TLS-specific listening configuration for inbound connections."; leaf address { type inet:ip-address; description "The IP address to listen on for incoming connections. The RESTCONF server will listen on all configured interfaces if no value is specified. INADDR_ANY (0.0.0.0) or INADDR6_ANY (0:0:0:0:0:0:0:0 a.k.a. ::) MUST be used when the server is to listen on all IPv4 or IPv6 addresses, respectively."; } leaf port { type inet:port-number; default 443; description "The local port number to listen on. If no value is specified, the IANA-assigned port value for 'https' (443) is used."; } uses ts:tls-server-grouping { refine "client-auth" { must 'pinned-ca-certs or pinned-client-certs'; description "RESTCONF servers MUST be able to validate clients."; } augment "client-auth" { description "Augments in the cert-to-name structure, so the RESTCONF server can map TLS-layer client certificates to RESTCONF usernames."; 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, Watsen & Wu Expires December 6, 2018 [Page 26] Internet-Draft RESTCONF Client and Server Models June 2018 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."; } } } } // end tls container } // end tls case } // end transport } // end endpoint } // end listen container call-home { if-feature call-home; presence "Enables server to initiate TCP connections"; description "Configures call-home behavior"; list restconf-client { key name; min-elements 1; description "List of RESTCONF clients the RESTCONF server is to initiate call-home connections to in parallel."; 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."; } choice transport { mandatory true; Watsen & Wu Expires December 6, 2018 [Page 27] Internet-Draft RESTCONF Client and Server Models June 2018 description "Selects between available transports. This is a 'choice' statement so as to support additional transport options to be augmented in."; case tls { if-feature tls-call-home; container tls { description "Specifies TLS-specific call-home transport configuration."; leaf address { type inet:host; mandatory true; description "The IP address or hostname of the endpoint. If a domain name is configured, then the DNS resolution should happen on each usage attempt. If the DNS resolution results in multiple IP addresses, the IP addresses will be tried according to local preference order until a connection has been established or until all IP addresses have failed."; } leaf port { type inet:port-number; default 4336; description "The IP port for this endpoint. The RESTCONF server will use the IANA-assigned well-known port for 'restconf-ch-tls' (4336) if no value is specified."; } uses ts:tls-server-grouping { refine "client-auth" { must 'pinned-ca-certs or pinned-client-certs'; description "RESTCONF servers MUST be able to validate clients."; } augment "client-auth" { description "Augments in the cert-to-name structure, so the RESTCONF server can map TLS-layer client certificates to RESTCONF usernames."; container cert-maps { uses x509c2n:cert-to-name; description "The cert-maps container is used by a Watsen & Wu Expires December 6, 2018 [Page 28] Internet-Draft RESTCONF Client and Server Models June 2018 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 7407: A YANG Data Model for SNMP Configuration."; } } } } } } // end transport } // end endpoint } // end endpoints container connection-type { description "Indicates the RESTCONF client's preference for how the RESTCONF server's connection is maintained."; choice connection-type { default persistent-connection; 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 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."; leaf idle-timeout { type uint32; units "seconds"; default 86400; // one day; description "Specifies the maximum number of seconds that Watsen & Wu Expires December 6, 2018 [Page 29] Internet-Draft RESTCONF Client and Server Models June 2018 the underlying TLS session may remain idle. A TLS 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."; } 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 8071: 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 "Indicates that a periodic connection is to be maintained."; Watsen & Wu Expires December 6, 2018 [Page 30] Internet-Draft RESTCONF Client and Server Models June 2018 description "Periodically connect to the RESTCONF client, so that the RESTCONF client may send requests pending for the RESTCONF server. Once the connection has been closed, for whatever reason, the server will restart its timer until the next connection."; leaf idle-timeout { type uint16; units "seconds"; default 300; // five minutes description "Specifies the maximum number of seconds that the underlying TLS session may remain idle. A TLS 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."; } 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)."; Watsen & Wu Expires December 6, 2018 [Page 31] Internet-Draft RESTCONF Client and Server Models June 2018 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)."; } } } } } } 4. Security Considerations The YANG module defined in this document uses a grouping defined in [I-D.ietf-netconf-tls-client-server]. Please see the Security Considerations section in that document for concerns related that grouping. Watsen & Wu Expires December 6, 2018 [Page 32] Internet-Draft RESTCONF Client and Server Models June 2018 The YANG module defined in this document is 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) [RFC6536] provides the means to restrict access for particular users to a pre-configured subset of all available protocol operations and content. There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/vulnerability: /: The entire data trees defined by the modules defined in this draft are sensitive to write operations. For instance, the addition or removal of references to keys, certificates, trusted anchors, etc., can dramatically alter the implemented security policy. However, no NACM annotations are applied as the data SHOULD be editable by users other than a designated 'recovery session'. Some of the readable data nodes in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control read access (e.g., via get, get-config, or notification) to these data nodes. These are the subtrees and data nodes and their sensitivity/vulnerability: NONE Some of the RPC operations in this YANG module may be considered sensitive or vulnerable in some network environments. It is thus important to control access to these operations. These are the operations and their sensitivity/vulnerability: NONE 5. IANA Considerations 5.1. The IETF XML Registry This document registers two URIs in the IETF XML registry [RFC3688]. Following the format in [RFC3688], the following registrations are requested: Watsen & Wu Expires December 6, 2018 [Page 33] Internet-Draft RESTCONF Client and Server Models June 2018 URI: urn:ietf:params:xml:ns:yang:ietf-restconf-client Registrant Contact: The NETCONF WG of the IETF. XML: N/A, the requested URI is an XML namespace. URI: urn:ietf:params:xml:ns:yang:ietf-restconf-server Registrant Contact: The NETCONF WG of the IETF. 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 [RFC7950]. Following the format in [RFC7950], the the following registrations are requested: name: ietf-restconf-client namespace: urn:ietf:params:xml:ns:yang:ietf-restconf-client prefix: ncc reference: RFC XXXX name: ietf-restconf-server namespace: urn:ietf:params:xml:ns:yang:ietf-restconf-server prefix: ncs reference: RFC XXXX 6. References 6.1. Normative References [I-D.ietf-netconf-keystore] Watsen, K., "YANG Data Model for a "Keystore" Mechanism", draft-ietf-netconf-keystore-04 (work in progress), October 2017. [I-D.ietf-netconf-tls-client-server] Watsen, K. and G. Wu, "YANG Groupings for TLS Clients and TLS Servers", draft-ietf-netconf-tls-client-server-05 (work in progress), October 2017. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, . Watsen & Wu Expires December 6, 2018 [Page 34] Internet-Draft RESTCONF Client and Server Models June 2018 [RFC7407] Bjorklund, M. and J. Schoenwaelder, "A YANG Data Model for SNMP Configuration", RFC 7407, DOI 10.17487/RFC7407, December 2014, . [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8071] Watsen, K., "NETCONF Call Home and RESTCONF Call Home", RFC 8071, DOI 10.17487/RFC8071, February 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 6.2. Informative References [I-D.ietf-netconf-netconf-client-server] Watsen, K. and G. Wu, "NETCONF Client and Server Models", draft-ietf-netconf-netconf-client-server-05 (work in progress), October 2017. [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, August 2008, . [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., and A. Bierman, Ed., "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, . [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, DOI 10.17487/RFC6536, March 2012, . Watsen & Wu Expires December 6, 2018 [Page 35] Internet-Draft RESTCONF Client and Server Models June 2018 [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, . Watsen & Wu Expires December 6, 2018 [Page 36] Internet-Draft RESTCONF Client and Server Models June 2018 Appendix A. Change Log A.1. 00 to 01 o Renamed "keychain" to "keystore". A.2. 01 to 02 o Filled in previously missing 'ietf-restconf-client' module. o Updated the ietf-restconf-server module to accomodate new grouping 'ietf-tls-server-grouping'. A.3. 02 to 03 o Refined use of tls-client-grouping to add a must statement indicating that the TLS client must specify a client-certificate. o Changed restconf-client??? to be a grouping (not a container). A.4. 03 to 04 o Added RFC 8174 to Requirements Language Section. o Replaced refine statement in ietf-restconf-client to add a mandatory true. o Added refine statement in ietf-restconf-server to add a must statement. o Now there are containers and groupings, for both the client and server models. o Now tree diagrams reference ietf-netmod-yang-tree-diagrams o Updated examples to inline key and certificates (no longer a leafref to keystore) A.5. 04 to 05 o Now tree diagrams reference ietf-netmod-yang-tree-diagrams o Updated examples to inline key and certificates (no longer a leafref to keystore) Watsen & Wu Expires December 6, 2018 [Page 37] Internet-Draft RESTCONF Client and Server Models June 2018 A.6. 05 to 06 o Fixed change log missing section issue. o Updated examples to match latest updates to the crypto-types, trust-anchors, and keystore drafts. o Reduced line length of the YANG modules to fit within 69 columns. Acknowledgements The authors would like to thank for following for lively discussions on list and in the halls (ordered by last name): Andy Bierman, Martin Bjorklund, Benoit Claise, Mehmet Ersue, Balazs Kovacs, David Lamparter, Alan Luchuk, Ladislav Lhotka, Radek Krejci, Tom Petch, Juergen Schoenwaelder, Phil Shafer, Sean Turner, and Bert Wijnen. Authors' Addresses Kent Watsen Juniper Networks EMail: kwatsen@juniper.net Gary Wu Cisco Networks EMail: garywu@cisco.com Watsen & Wu Expires December 6, 2018 [Page 38]