NETCONF Working Group K. Watsen Internet-Draft Watsen Networks Intended status: Standards Track M. Scharf Expires: January 3, 2020 Hochschule Esslingen July 2, 2019 YANG Groupings for TCP Clients and TCP Servers draft-ietf-netconf-tcp-client-server-02 Abstract This document defines three YANG modules: the first defines a grouping for configuring a generic TCP client, the second defines a grouping for configuring a generic TCP server, and the third defines a grouping common to the TCP clients and TCP servers. 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. Artwork in this document contains placeholder values for the date of publication of this draft. Please apply the following replacement: o "2019-07-02" --> the publication date of this draft The following Appendix section is to be removed prior to publication: 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." Watsen & Scharf Expires January 3, 2020 [Page 1] Internet-Draft Groupings for TCP Clients and Servers July 2019 This Internet-Draft will expire on January 3, 2020. Copyright Notice Copyright (c) 2019 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 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. The TCP Client Model . . . . . . . . . . . . . . . . . . . . 3 3.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 3 3.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 3 3.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 4 4. The TCP Server Model . . . . . . . . . . . . . . . . . . . . 7 4.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 7 4.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 7 4.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 8 5. The TCP Common Model . . . . . . . . . . . . . . . . . . . . 10 5.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 10 5.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 11 5.3. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 11 6. Security Considerations . . . . . . . . . . . . . . . . . . . 14 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 7.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 15 7.2. The YANG Module Names Registry . . . . . . . . . . . . . 15 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 8.1. Normative References . . . . . . . . . . . . . . . . . . 16 8.2. Informative References . . . . . . . . . . . . . . . . . 16 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 18 A.1. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . 18 A.2. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 Watsen & Scharf Expires January 3, 2020 [Page 2] Internet-Draft Groupings for TCP Clients and Servers July 2019 1. Introduction This document defines three YANG 1.1 [RFC7950] modules: the first defines a grouping for configuring a generic TCP client, the second defines a grouping for configuring a generic TCP server, and the third defines a grouping common to the TCP clients and TCP servers. It is intended that these groupings will be used either standalone, for TCP-based protocols, as part of a stack of protocol-specific configuration models. For instance, these groupings could help define the configuration module for SSH, TLS, or HTTP based applications. 2. 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. 3. The TCP Client Model 3.1. Tree Diagram This section provides a tree diagram [RFC8340] for the "ietf-tcp- client" module. module: ietf-tcp-client grouping tcp-client-grouping +-- remote-address inet:host +-- remote-port? inet:port-number +-- local-address? inet:ip-address {local-binding-supported}? +-- local-port? inet:port-number {local-binding-supported}? +-- keepalives! {keepalives-supported}? +-- idle-time uint16 +-- max-probes uint16 +-- probe-interval uint16 3.2. Example Usage This section presents an example showing the tcp-client-grouping populated with some data. Watsen & Scharf Expires January 3, 2020 [Page 3] Internet-Draft Groupings for TCP Clients and Servers July 2019 www.example.com 443 0.0.0.0 0 15 3 30 3.3. YANG Module The ietf-tcp-client YANG module references [RFC6991]. file "ietf-tcp-client@2019-07-02.yang" module ietf-tcp-client { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-tcp-client"; prefix tcpc; import ietf-inet-types { prefix inet; reference "RFC 6991: Common YANG Data Types"; } import ietf-tcp-common { prefix tcpcmn; reference "RFC XXXX: YANG Groupings for TCP Clients and TCP Servers"; } organization "IETF NETCONF (Network Configuration) Working Group and the IETF TCP Maintenance and Minor Extensions (TCPM) Working Group"; contact "WG Web: WG List: Authors: Kent Watsen Michael Scharf "; description Watsen & Scharf Expires January 3, 2020 [Page 4] Internet-Draft Groupings for TCP Clients and Servers July 2019 "This module defines reusable groupings for TCP clients that can be used as a basis for specific TCP client instances. Copyright (c) 2019 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 (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself for full legal notices.; The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document are to be interpreted as described in BCP 14 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here."; revision 2019-07-02 { description "Initial version"; reference "RFC XXXX: YANG Groupings for TCP Clients and TCP Servers"; } // Features feature local-binding-supported { description "Indicates that the server supports configuring local bindings (i.e., the local address and local port) for TCP clients."; } feature tcp-client-keepalives { description "Per socket TCP keepalive parameters are configurable for TCP clients on the server implementing this feature."; } // Groupings Watsen & Scharf Expires January 3, 2020 [Page 5] Internet-Draft Groupings for TCP Clients and Servers July 2019 grouping tcp-client-grouping { description "A reusable grouping for configuring a TCP client. Note that this grouping uses fairly typical descendent node names such that a stack of 'uses' statements will have name conflicts. It is intended that the consuming data model will resolve the issue (e.g., by wrapping the 'uses' statement in a container called 'tcp-client-parameters'). This model purposely does not do this itself so as to provide maximum flexibility to consuming models."; leaf remote-address { type inet:host; mandatory true; description "The IP address or hostname of the remote peer to establish a connection with. If a domain name is configured, then the DNS resolution should happen on each connection attempt. If the the DNS resolution results in multiple IP addresses, the IP addresses are tried according to local preference order until a connection has been established or until all IP addresses have failed."; } leaf remote-port { type inet:port-number; default "0"; description "The IP port number for the remote peer to establish a connection with. An invalid default value (0) is used (instead of 'mandatory true') so that as application level data model may 'refine' it with an application specific default port number value."; } leaf local-address { if-feature "local-binding-supported"; type inet:ip-address; description "The local IP address/interface (VRF?) to bind to for when connecting to the remote peer. INADDR_ANY ('0.0.0.0') or INADDR6_ANY ('0:0:0:0:0:0:0:0' a.k.a. '::') MAY be used to explicitly indicate the implicit default, that the server can bind to any IPv4 or IPv6 addresses, respectively."; } leaf local-port { if-feature "local-binding-supported"; Watsen & Scharf Expires January 3, 2020 [Page 6] Internet-Draft Groupings for TCP Clients and Servers July 2019 type inet:port-number; default "0"; description "The local IP port number to bind to for when connecting to the remote peer. The port number '0', which is the default value, indicates that any available local port number may be used."; } uses tcpcmn:tcp-connection-grouping { augment "keepalives" { if-feature "tcp-client-keepalives"; description "Add an if-feature statement so that implementations can choose to support TCP client keepalives."; } } } } 4. The TCP Server Model 4.1. Tree Diagram This section provides a tree diagram [RFC8340] for the "ietf-tcp- server" module. module: ietf-tcp-server grouping tcp-server-grouping +-- local-address inet:ip-address +-- local-port? inet:port-number +-- keepalives! {keepalives-supported}? +-- idle-time uint16 +-- max-probes uint16 +-- probe-interval uint16 4.2. Example Usage This section presents an example showing the tcp-server-grouping populated with some data. Watsen & Scharf Expires January 3, 2020 [Page 7] Internet-Draft Groupings for TCP Clients and Servers July 2019 10.20.30.40 7777 15 3 30 4.3. YANG Module The ietf-tcp-server YANG module references [RFC6991]. file "ietf-tcp-server@2019-07-02.yang" module ietf-tcp-server { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-tcp-server"; prefix tcps; import ietf-inet-types { prefix inet; reference "RFC 6991: Common YANG Data Types"; } import ietf-tcp-common { prefix tcpcmn; reference "RFC XXXX: YANG Groupings for TCP Clients and TCP Servers"; } organization "IETF NETCONF (Network Configuration) Working Group and the IETF TCP Maintenance and Minor Extensions (TCPM) Working Group"; contact "WG Web: WG List: Authors: Kent Watsen Michael Scharf "; description "This module defines reusable groupings for TCP servers that can be used as a basis for specific TCP server instances. Watsen & Scharf Expires January 3, 2020 [Page 8] Internet-Draft Groupings for TCP Clients and Servers July 2019 Copyright (c) 2019 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 (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself for full legal notices.; The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document are to be interpreted as described in BCP 14 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here."; revision 2019-07-02 { description "Initial version"; reference "RFC XXXX: YANG Groupings for TCP Clients and TCP Servers"; } // Features feature tcp-server-keepalives { description "Per socket TCP keepalive parameters are configurable for TCP servers on the server implementing this feature."; } // Groupings grouping tcp-server-grouping { description "A reusable grouping for configuring a TCP server. Note that this grouping uses fairly typical descendent node names such that a stack of 'uses' statements will have name conflicts. It is intended that the consuming data model will resolve the issue (e.g., by wrapping the 'uses' statement in a container called Watsen & Scharf Expires January 3, 2020 [Page 9] Internet-Draft Groupings for TCP Clients and Servers July 2019 'tcp-server-parameters'). This model purposely does not do this itself so as to provide maximum flexibility to consuming models."; leaf local-address { type inet:ip-address; mandatory true; description "The local IP address to listen on for incoming TCP client connections. 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 local-port { type inet:port-number; default "0"; description "The local port number to listen on for incoming TCP client connections. An invalid default value (0) is used (instead of 'mandatory true') so that an application level data model may 'refine' it with an application specific default port number value."; } uses tcpcmn:tcp-connection-grouping { augment "keepalives" { if-feature "tcp-server-keepalives"; description "Add an if-feature statement so that implementations can choose to support TCP server keepalives."; } } } } 5. The TCP Common Model 5.1. Tree Diagram This section provides a tree diagram [RFC8340] for the "ietf-tcp- common" module. Watsen & Scharf Expires January 3, 2020 [Page 10] Internet-Draft Groupings for TCP Clients and Servers July 2019 module: ietf-tcp-common grouping tcp-common-grouping +-- keepalives! {keepalives-supported}? +-- idle-time uint16 +-- max-probes uint16 +-- probe-interval uint16 grouping tcp-connection-grouping +-- keepalives! {keepalives-supported}? +-- idle-time uint16 +-- max-probes uint16 +-- probe-interval uint16 5.2. Example Usage This section presents an example showing the tcp-common-grouping populated with some data. 15 3 30 5.3. YANG Module The ietf-tcp-common YANG module references [RFC6991]. file "ietf-tcp-common@2019-07-02.yang" module ietf-tcp-common { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-tcp-common"; prefix tcpcmn; organization "IETF NETCONF (Network Configuration) Working Group and the IETF TCP Maintenance and Minor Extensions (TCPM) Working Group"; contact "WG Web: WG List: Authors: Kent Watsen Michael Scharf "; Watsen & Scharf Expires January 3, 2020 [Page 11] Internet-Draft Groupings for TCP Clients and Servers July 2019 description "This module defines reusable groupings for TCP commons that can be used as a basis for specific TCP common instances. Copyright (c) 2019 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 (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself for full legal notices.; The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document are to be interpreted as described in BCP 14 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here."; revision 2019-07-02 { description "Initial version"; reference "RFC XXXX: YANG Groupings for TCP Clients and TCP Servers"; } // Features feature keepalives-supported { description "Indicates that keepalives are supported."; } // Groupings grouping tcp-common-grouping { description "A reusable grouping for configuring TCP parameters common to TCP connections as well as the operating system as a whole."; container keepalives { if-feature "keepalives-supported"; presence "Indicates that keepalives are enabled."; Watsen & Scharf Expires January 3, 2020 [Page 12] Internet-Draft Groupings for TCP Clients and Servers July 2019 description "Configures the keep-alive policy, to proactively test the aliveness of the TCP peer. An unresponsive TCP peer is dropped after approximately (idle-time * 60) + (max-probes * probe-interval) seconds."; leaf idle-time { type uint16 { range "1..max"; } units "seconds"; mandatory true; description "Sets the amount of time after which if no data has been received from the TCP peer, a TCP-level probe message will be sent to test the aliveness of the TCP peer."; } leaf max-probes { type uint16 { range "1..max"; } mandatory true; description "Sets the maximum number of sequential keep-alive probes that can fail to obtain a response from the TCP peer before assuming the TCP peer is no longer alive."; } leaf probe-interval { type uint16 { range "1..max"; } units "seconds"; mandatory true; description "Sets the time interval between failed probes."; } } // container keepalives } // grouping tcp-common-grouping grouping tcp-connection-grouping { description "A reusable grouping for configuring TCP parameters common to TCP connections."; uses tcp-common-grouping; } /* The following is for a future bis... Watsen & Scharf Expires January 3, 2020 [Page 13] Internet-Draft Groupings for TCP Clients and Servers July 2019 This comment is here now so as support discussion with TCPM. This comment will be removed before publication. Should future system-level parameters be defined as a grouping or a container? grouping tcp-system-grouping { description "A reusable grouping for configuring TCP parameters common to the operating system as a whole."; // currently just a placeholder } */ } 6. Security Considerations The YANG modules defined in this document are designed to be accessed via YANG based management protocols, such as NETCONF [RFC6241] and RESTCONF [RFC8040]. Both of these protocols have mandatory-to- implement secure transport layers (e.g., SSH, TCP) with mutual authentication. The NETCONF access control model (NACM) [RFC8341] provides the means to restrict access for particular users to a pre-configured subset of all available protocol operations and content. Since the modules defined in this document only define groupings, these considerations are primarily for the designers of other modules that use these groupings. There are a number of data nodes defined in the YANG modules 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 of the writable/creatable/deletable data nodes in the YANG modules defined in this document are considered more sensitive or vulnerable then standard configuration. Some of the readable data nodes in the YANG modules may be considered sensitive or vulnerable in some network environments. It is thus Watsen & Scharf Expires January 3, 2020 [Page 14] Internet-Draft Groupings for TCP Clients and Servers July 2019 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 of the readable data nodes in the YANG modules defined in this document are considered more sensitive or vulnerable then standard configuration. This document does not define any RPC actions and hence this section does not consider the security of RPCs. 7. IANA Considerations 7.1. The IETF XML Registry This document registers two URIs in the "ns" subregistry of the IETF XML Registry [RFC3688]. Following the format in [RFC3688], the following registrations are requested: URI: urn:ietf:params:xml:ns:yang:ietf-tcp-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-tcp-server Registrant Contact: The NETCONF WG of the IETF. XML: N/A, the requested URI is an XML namespace. 7.2. The YANG Module Names Registry This document registers two YANG modules in the YANG Module Names registry [RFC6020]. Following the format in [RFC6020], the following registrations are requested: name: ietf-tcp-common namespace: urn:ietf:params:xml:ns:yang:ietf-tcp-common prefix: tcpcmn reference: RFC XXXX name: ietf-tcp-client namespace: urn:ietf:params:xml:ns:yang:ietf-tcp-client prefix: tcpc reference: RFC XXXX name: ietf-tcp-server namespace: urn:ietf:params:xml:ns:yang:ietf-tcp-server prefix: tcps reference: RFC XXXX Watsen & Scharf Expires January 3, 2020 [Page 15] Internet-Draft Groupings for TCP Clients and Servers July 2019 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, . [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, . [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018, . 8.2. Informative References [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [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 & Scharf Expires January 3, 2020 [Page 16] Internet-Draft Groupings for TCP Clients and Servers July 2019 [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, . Watsen & Scharf Expires January 3, 2020 [Page 17] Internet-Draft Groupings for TCP Clients and Servers July 2019 Appendix A. Change Log A.1. 00 to 01 o Added 'local-binding-supported' feature to TCP-client model. o Added 'keepalives-supported' feature to TCP-common model. o Added 'external-endpoint-values' container and 'external- endpoints' feature to TCP-server model. A.2. 01 to 02 o Removed the 'external-endpoint-values' container and 'external- endpoints' feature from the TCP-server model. Authors' Addresses Kent Watsen Watsen Networks EMail: kent+ietf@watsen.net Michael Scharf Hochschule Esslingen - University of Applied Sciences EMail: michael.scharf@hs-esslingen.de Watsen & Scharf Expires January 3, 2020 [Page 18]