NETCONF Working Group K. Watsen Internet-Draft Juniper Networks Intended status: Standards Track J. Schoenwaelder Expires: January 4, 2018 Jacobs University Bremen July 3, 2017 RESTCONF Client and Server Models draft-ietf-netconf-restconf-client-server-04 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 "2017-07-03" --> the publication date of this draft The following Appendix section is to be removed prior to publication: Watsen & Schoenwaelder Expires January 4, 2018 [Page 1] Internet-Draft RESTCONF Client and Server Models July 2017 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 http://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 January 4, 2018. Copyright Notice Copyright (c) 2017 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 (http://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 1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 3 2. The RESTCONF Client Model . . . . . . . . . . . . . . . . . . 4 2.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 6 2.3. YANG Model . . . . . . . . . . . . . . . . . . . . . . . 8 3. The RESTCONF Server Model . . . . . . . . . . . . . . . . . . 16 3.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 17 3.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 18 3.3. YANG Model . . . . . . . . . . . . . . . . . . . . . . . 20 4. Security Considerations . . . . . . . . . . . . . . . . . . . 29 Watsen & Schoenwaelder Expires January 4, 2018 [Page 2] Internet-Draft RESTCONF Client and Server Models July 2017 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30 5.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 30 5.2. The YANG Module Names Registry . . . . . . . . . . . . . 31 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 31 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 31 7.1. Normative References . . . . . . . . . . . . . . . . . . 31 7.2. Informative References . . . . . . . . . . . . . . . . . 32 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 34 A.1. server-model-09 to 00 . . . . . . . . . . . . . . . . . . 34 A.2. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . 34 A.3. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . 34 A.4. 02 to 03 . . . . . . . . . . . . . . . . . . . . . . . . 34 A.5. 03 to 04 . . . . . . . . . . . . . . . . . . . . . . . . 34 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 34 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. 1.2. Tree Diagrams A simplified graphical representation of the data models is used in this document. The meaning of the symbols in these diagrams is as follows: o Brackets "[" and "]" enclose list keys. o Braces "{" and "}" enclose feature names, and indicate that the named feature must be present for the subtree to be present. o Abbreviations before data node names: "rw" means configuration (read-write) and "ro" state data (read-only). o Symbols after data node names: "?" means an optional node, "!" means a presence container, and "*" denotes a list and leaf-list. Watsen & Schoenwaelder Expires January 4, 2018 [Page 3] Internet-Draft RESTCONF Client and Server Models July 2017 o Parentheses enclose choice and case nodes, and case nodes are also marked with a colon (":"). o Ellipsis ("...") stands for contents of subtrees that are not shown. 2. The RESTCONF Client Model EDITOR NOTE: Please ignore this section, it is incomplete. 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 supports the TLS transport protocol using the TLS client groupings defined in [I-D.ietf-netconf-tls-client-server]. 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. 2.1. Tree Diagram Just the container is displayed below, but there is also a grouping that the container is using. Note: all lines are folded at column 71 with no '\' character. module: ietf-restconf-client +--rw restconf-client +--rw initiate {initiate}? | +--rw restconf-server* [name] | +--rw name string | +--rw (transport) | | +--:(tls) {tls-initiate}? | | +--rw tls | | +--rw endpoints | | | +--rw endpoint* [name] | | | +--rw name string | | | +--rw address inet:host | | | +--rw port? inet:port-number | | +--rw server-auth | | | +--rw trusted-ca-certs? leafref | | | +--rw trusted-server-certs? leafref | | +--rw client-auth | | | +--rw (auth-type) Watsen & Schoenwaelder Expires January 4, 2018 [Page 4] Internet-Draft RESTCONF Client and Server Models July 2017 | | | +--:(certificate) | | | +--rw certificate? leafref | | +--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 max-sessions? uint16 +--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 server-auth | +--rw trusted-ca-certs? leafref | +--rw trusted-server-certs? leafref +--rw client-auth | +--rw (auth-type) | +--:(certificate) | +--rw certificate? leafref +--rw hello-params {tls-client-hello-params-config}? +--rw tls-versions | +--rw tls-version* identityref +--rw cipher-suites +--rw cipher-suite* identityref Watsen & Schoenwaelder Expires January 4, 2018 [Page 5] Internet-Draft RESTCONF Client and Server Models July 2017 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]. Watsen & Schoenwaelder Expires January 4, 2018 [Page 6] Internet-Draft RESTCONF Client and Server Models July 2017 corp-fw1 corp-fw1.example.com
corp-fw1.example.com
corp-fw2.example.com
corp-fw2.example.com
deployment-specific-ca-certs tls-ec-cert
Intranet-facing listener
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deployment-specific-ca-certs explicitly-trusted-server-certs tls-ec-cert
Watsen & Schoenwaelder Expires January 4, 2018 [Page 7] Internet-Draft RESTCONF Client and Server Models July 2017 2.3. YANG Model This YANG module imports YANG types from [RFC6991] and [RFC7407]. file "ietf-restconf-client@2017-07-03.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 2017-06-13; // stable grouping definitions reference "RFC ZZZZ: TLS Client and Server Models"; } organization "IETF NETCONF (Network Configuration) Working Group"; 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) 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 Watsen & Schoenwaelder Expires January 4, 2018 [Page 8] Internet-Draft RESTCONF Client and Server Models July 2017 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 "2017-07-03" { 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 { description "The 'tls-initiate' feature indicates that the RESTCONF client supports initiating TLS connections to RESTCONF servers."; 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 { description "The 'tls-listen' feature indicates that the RESTCONF client supports opening a port to listen for incoming RESTCONF server call-home TLS connections."; reference "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; Watsen & Schoenwaelder Expires January 4, 2018 [Page 9] Internet-Draft RESTCONF Client and Server Models July 2017 } 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; description "Configures client initiating underlying TCP connections."; list restconf-server { key name; description "List of RESTCONF servers the RESTCONF client is to initiate connections to."; leaf name { type string; description "An arbitrary name for the RESTCONF server."; } choice transport { mandatory true; description "Selects between available transports."; case tls { if-feature tls-initiate; container tls { description "Specifies TLS-specific transport configuration."; uses endpoints-container { refine endpoints/endpoint/port { default 443; } } uses ts:tls-client-grouping { refine "client-auth/auth-type" { mandatory true; description "RESTCONF clients MUST pass some authentication credentials."; } Watsen & Schoenwaelder Expires January 4, 2018 [Page 10] Internet-Draft RESTCONF Client and Server Models July 2017 } } } // end tls } // end transport container connection-type { description "Indicates the kind of connection to use."; choice connection-type { description "Selects between available connection types."; case persistent-connection { container persistent { presence true; 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 a a RESTCONF session may remain idle. A RESTCONF session will be dropped if it is idle for an interval longer than this number of seconds. If set to zero, then 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 SSH/TLS server. An unresponsive SSH/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 { Watsen & Schoenwaelder Expires January 4, 2018 [Page 11] Internet-Draft RESTCONF Client and Server Models July 2017 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 SSH/TLS server, a SSH/TLS-level message will be sent to test the aliveness of the SSH/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 SSH/TLS server before assuming the SSH/TLS server is no longer alive."; } } } } case periodic-connection { container periodic { presence true; description "Periodically connect to the RESTCONF server, so that the RESTCONF server may deliver messages pending for the RESTCONF client. The RESTCONF server must close the connection when it is ready to release it. Once the connection has been closed, 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 a a RESTCONF session may remain idle. A RESTCONF 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 { Watsen & Schoenwaelder Expires January 4, 2018 [Page 12] Internet-Draft RESTCONF Client and Server Models July 2017 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)."; } } } } } 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."; } } 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."; } Watsen & Schoenwaelder Expires January 4, 2018 [Page 13] Internet-Draft RESTCONF Client and Server Models July 2017 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 restconf-server } // end initiate container listen { if-feature listen; description "Configures client accepting call-home TCP connections."; leaf max-sessions { type uint16; default 0; 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."; } leaf idle-timeout { type uint16; units "seconds"; default 3600; // one hour description "Specifies the maximum number of seconds that a RESTCONF session may remain idle. A RESTCONF 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; description "List of endpoints to listen for RESTCONF connections."; leaf name { type string; description Watsen & Schoenwaelder Expires January 4, 2018 [Page 14] Internet-Draft RESTCONF Client and Server Models July 2017 "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."; leaf address { type inet:ip-address; description "The IP address to listen for call-home connections."; } leaf port { type inet:port-number; default 4336; description "The port number to listen for call-home connections."; } uses ts:tls-client-grouping { refine "client-auth/auth-type" { mandatory true; description "RESTCONF clients MUST pass some authentication credentials."; } } } } } // end transport } // end endpoint } // end listen } // end restconf-client grouping endpoints-container { description "This grouping is used to configure a set of RESTCONF servers a RESTCONF client may initiate connections to."; container endpoints { description "Container for the list of endpoints."; list endpoint { Watsen & Schoenwaelder Expires January 4, 2018 [Page 15] Internet-Draft RESTCONF Client and Server Models July 2017 key name; unique "address port"; min-elements 1; ordered-by user; description "A non-empty user-ordered list of endpoints for this RESTCONF client to try to connect to. 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 client 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 client will use the IANA-assigned well-known port (set via a refine statement when uses) if no value is specified."; } } } } } 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. This model supports the TLS transport protocol using the TLS server groupings defined in [I-D.ietf-netconf-tls-client-server]. All private keys and trusted certificates are held in the keystore model defined in [I-D.ietf-netconf-keystore]. Watsen & Schoenwaelder Expires January 4, 2018 [Page 16] Internet-Draft RESTCONF Client and Server Models July 2017 YANG feature statements are used to enable implementations to advertise which parts of the model the RESTCONF server supports. 3.1. Tree Diagram Just the container is displayed below, but there is also a grouping that the container is using. Note: all lines are folded at column 71 with no '\' character. module: ietf-restconf-server +--rw restconf-server +--rw listen {listen}? | +--rw max-sessions? 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 certificates | | +--rw certificate* [name] | | +--rw name leafref | +--rw client-auth | | +--rw trusted-ca-certs? leafref | | +--rw trusted-client-certs? leafref | | +--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 (transport) | +--:(tls) {tls-call-home}? | +--rw tls | +--rw endpoints | | +--rw endpoint* [name] | | +--rw name string Watsen & Schoenwaelder Expires January 4, 2018 [Page 17] Internet-Draft RESTCONF Client and Server Models July 2017 | | +--rw address inet:host | | +--rw port? inet:port-number | +--rw certificates | | +--rw certificate* [name] | | +--rw name leafref | +--rw client-auth | | +--rw trusted-ca-certs? leafref | | +--rw trusted-client-certs? leafref | | +--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 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 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]. Watsen & Schoenwaelder Expires January 4, 2018 [Page 18] Internet-Draft RESTCONF Client and Server Models July 2017 netconf/tls
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tls-ec-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
Watsen & Schoenwaelder Expires January 4, 2018 [Page 19] Internet-Draft RESTCONF Client and Server Models July 2017 tls-ec-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 60 last-connected 3
3.3. YANG Model This YANG module imports YANG types from [RFC6991] and [RFC7407]. file "ietf-restconf-server@2017-07-03.yang" module ietf-restconf-server { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-restconf-server"; prefix "rcs"; Watsen & Schoenwaelder Expires January 4, 2018 [Page 20] Internet-Draft RESTCONF Client and Server Models July 2017 //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 2017-06-13; // 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 Watsen & Schoenwaelder Expires January 4, 2018 [Page 21] Internet-Draft RESTCONF Client and Server Models July 2017 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 "2017-07-03" { 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 8071: NETCONF Call Home and RESTCONF Call Home"; } feature tls-call-home { Watsen & Schoenwaelder Expires January 4, 2018 [Page 22] Internet-Draft RESTCONF Client and Server Models July 2017 description "The 'tls-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 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 { 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; 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."; leaf name { type string; description "An arbitrary name for the RESTCONF listen endpoint."; } Watsen & Schoenwaelder Expires January 4, 2018 [Page 23] Internet-Draft RESTCONF Client and Server Models July 2017 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."; leaf address { type inet:ip-address; description "The IP address of the interface to listen on. The TLS server will listen on all interfaces if no value is specified. Please note that some addresses have special meanings (e.g., '0.0.0.0' and '::')."; } leaf port { type inet:port-number; default 443; description "The local port number on this interface the TLS server listens on."; } uses ts:tls-server-grouping { refine "client-auth" { must 'trusted-ca-certs or trusted-client-certs'; description "RESTCONF servers MUST be able to validate clients."; } augment "client-auth" { description "Augments in the cert-to-name structure."; uses cert-maps-grouping; } } } // end tls container } // end tls case } // end transport } // end endpoint } // end listen container call-home { if-feature call-home; description "Configures call-home behavior"; list restconf-client { Watsen & Schoenwaelder Expires January 4, 2018 [Page 24] Internet-Draft RESTCONF Client and Server Models July 2017 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:tls-server-grouping { refine "client-auth" { must 'trusted-ca-certs or trusted-client-certs'; description "RESTCONF servers MUST be able to validate clients."; } 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 { Watsen & Schoenwaelder Expires January 4, 2018 [Page 25] Internet-Draft RESTCONF Client and Server Models July 2017 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 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 true; Watsen & Schoenwaelder Expires January 4, 2018 [Page 26] Internet-Draft RESTCONF Client and Server Models July 2017 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 Watsen & Schoenwaelder Expires January 4, 2018 [Page 27] Internet-Draft RESTCONF Client and Server Models July 2017 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."; Watsen & Schoenwaelder Expires January 4, 2018 [Page 28] Internet-Draft RESTCONF Client and Server Models July 2017 container endpoints { description "Container for the list of endpoints."; list endpoint { key name; unique "address port"; 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."; } } } } } 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 Watsen & Schoenwaelder Expires January 4, 2018 [Page 29] Internet-Draft RESTCONF Client and Server Models July 2017 Considerations section in that document for concerns related that grouping. 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: NONE 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 & Schoenwaelder Expires January 4, 2018 [Page 30] Internet-Draft RESTCONF Client and Server Models July 2017 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. 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, Phil Shafer, Sean Turner, and Bert Wijnen. Juergen Schoenwaelder and was partly funded by Flamingo, a Network of Excellence project (ICT-318488) supported by the European Commission under its Seventh Framework Programme. 7. References 7.1. Normative References [I-D.ietf-netconf-keystore] Watsen, K., "Keystore Model", draft-ietf-netconf- keystore-02 (work in progress), June 2017. [I-D.ietf-netconf-tls-client-server] Watsen, K. and G. Wu, "TLS Client and Server Models", draft-ietf-netconf-tls-client-server-03 (work in progress), June 2017. Watsen & Schoenwaelder Expires January 4, 2018 [Page 31] Internet-Draft RESTCONF Client and Server Models July 2017 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, DOI 10.17487/RFC6536, March 2012, . [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, . [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, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . 7.2. Informative References [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, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . Watsen & Schoenwaelder Expires January 4, 2018 [Page 32] Internet-Draft RESTCONF Client and Server Models July 2017 [RFC8071] Watsen, K., "NETCONF Call Home and RESTCONF Call Home", RFC 8071, DOI 10.17487/RFC8071, February 2017, . Watsen & Schoenwaelder Expires January 4, 2018 [Page 33] Internet-Draft RESTCONF Client and Server Models July 2017 Appendix A. Change Log A.1. server-model-09 to 00 o This draft was split out from draft-ietf-netconf-server-model-09. o Added in new features 'listen' and 'call-home' so future transports can be augmented in. A.2. 00 to 01 o Renamed "keychain" to "keystore". A.3. 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.4. 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.5. 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. Authors' Addresses Kent Watsen Juniper Networks EMail: kwatsen@juniper.net Watsen & Schoenwaelder Expires January 4, 2018 [Page 34] Internet-Draft RESTCONF Client and Server Models July 2017 Juergen Schoenwaelder Jacobs University Bremen EMail: j.schoenwaelder@jacobs-university.de Watsen & Schoenwaelder Expires January 4, 2018 [Page 35]