NETCONF Working Group                                          K. Watsen
Internet-Draft                                           Watsen Networks
Intended status: Standards Track                        November 1, 2019
Expires: May 4, 2020


            YANG Groupings for HTTP Clients and HTTP Servers
              draft-kwatsen-netconf-http-client-server-05

Abstract

   This document defines two YANG modules: the first defines a minimal
   grouping for configuring a generic HTTP client, and the second
   defines a minimal grouping for configuring a generic HTTP server.  It
   is intended that these groupings will be used by higher-level HTTP-
   based protocols.

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  "2019-11-02" --> 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."




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   This Internet-Draft will expire on May 4, 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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  The HTTP Client Model . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   3
     3.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .   3
     3.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  The HTTP Server Model . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  Example Usage . . . . . . . . . . . . . . . . . . . . . .   8
     4.3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .   8
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
     6.1.  The IETF XML Registry . . . . . . . . . . . . . . . . . .  14
     6.2.  The YANG Module Names Registry  . . . . . . . . . . . . .  15
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  15
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  16
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  16

1.  Introduction

   This document defines two YANG 1.1 [RFC7950] modules: the first
   defines a grouping for configuring a generic HTTP client, and the
   second defines a grouping for configuring a generic HTTP server.  It
   is intended that these groupings will be used by higher-level HTTP-
   based protocols.






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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 HTTP Client Model

3.1.  Tree Diagram

   This section provides a tree diagram [RFC8340] for the "ietf-http-
   client" module.

   module: ietf-http-client

     grouping client-identity-grouping
       +-- (auth-type)
          +--:(basic)
             +-- basic {basic-auth}?
                +-- user-id     string
                +-- password    string
     grouping http-client-grouping
       +-- client-identity
       |  +---u client-identity-grouping
       +-- proxy-server! {proxy-connect}?
          +-- tcp-client-parameters
          |  +---u tcpc:tcp-client-grouping
          +-- tls-client-parameters
          |  +---u tlsc:tls-client-grouping
          +-- proxy-client-identity
             +---u client-identity-grouping

3.2.  Example Usage

   This section presents an example showing the http-client-grouping
   populated with some data.

   <http-client xmlns="urn:ietf:params:xml:ns:yang:ietf-http-client">
     <client-identity>
       <basic>
         <user-id>bob</user-id>
         <password>secret</password>
       </basic>
     </client-identity>
   </http-client>




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3.3.  YANG Module

   This YANG module has normative references to [RFC6991].

   <CODE BEGINS> file "ietf-http-client@2019-11-02.yang"

   module ietf-http-client {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-http-client";
     prefix httpc;

     import ietf-tcp-client {
       prefix tcpc;
       reference
         "RFC AAAA: YANG Groupings for TCP Clients and TCP Servers";
     }

     import ietf-tls-client {
       prefix tlsc;
       reference
         "RFC BBBB: YANG Groupings for TLS Clients and TLS Servers";
     }

     import ietf-netconf-acm {
       prefix nacm;
       reference
         "RFC 8341: Network Configuration Access Control Model";
     }

     organization
       "IETF NETCONF (Network Configuration) Working Group";

     contact
       "WG Web:   <http://datatracker.ietf.org/wg/netconf/>
        WG List:  <mailto:netconf@ietf.org>
        Author:   Kent Watsen <mailto:kent+ietf@watsen.net>";

     description
       "This module defines reusable groupings for HTTP clients that
        can be used as a basis for specific HTTP 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



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        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 2019-11-02 {
       description
         "Initial version";
       reference
         "RFC XXXX: YANG Groupings for HTTP Clients and HTTP Servers";
     }

     // Features

     feature proxy-connect {
       description
         "Proxy connection configuration is configurable for
          HTTP clients on the server implementing this feature.";
     }

     feature basic-auth {
       description
         "The 'basic-auth' feature indicates that the client
          may be configured to use the 'basic' HTTP authentication
          scheme.";
       reference
         "RFC 7617: The 'Basic' HTTP Authentication Scheme";
     }

     // Groupings

     grouping client-identity-grouping {
       description
         "The credentials used by the client to authenticate to
          the HTTP server.";
       choice auth-type {
         nacm:default-deny-write;
         mandatory true;
         description



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           "The authentication type.";
         case basic {
           container basic {
             if-feature "basic-auth";
             leaf user-id {
               type string;
               mandatory true;
               description
                 "The user-id for the authenticating client.";
             }
             leaf password {
               nacm:default-deny-all;
               type string;
               mandatory true;
               description
                 "The password for the authenticating client.";
             }
             description
               "The 'basic' HTTP scheme credentials.";
             reference
               "RFC 7617: The 'Basic' HTTP Authentication Scheme";
           }
         }
       }
     } // grouping client-identity-grouping

     grouping http-client-grouping {
       description
         "A reusable grouping for configuring a HTTP client,
          including the IP address and port number it initiates
          a connections to.

          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
          'http-client-parameters').  This model purposely does
          not do this itself so as to provide maximum flexibility
          to consuming models.";

       container client-identity {
         description
           "The identity the HTTP client should use when
            authenticating itself to the HTTP server.";
         uses client-identity-grouping;
       }




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       container proxy-server {
         nacm:default-deny-write;
         if-feature "proxy-connect";
         presence true; // only so ex-http-client can pass validation?
         container tcp-client-parameters {
           description
             "A wrapper around the TCP parameters to avoid
              name collisions.";
           uses "tcpc:tcp-client-grouping";
         }
         container tls-client-parameters {
           description
             "A wrapper around the TLS parameters to avoid
              name collisions.";
           uses "tlsc:tls-client-grouping";
         }
         container proxy-client-identity {
           description
             "The identity the HTTP client should use when
              authenticating itself to the HTTP server.";
           uses client-identity-grouping;
         }
         description
           "Proxy server settings.";
       }
     } // grouping http-client-grouping

   } // module ietf-http-client

   <CODE ENDS>

4.  The HTTP Server Model

4.1.  Tree Diagram

   This section provides a tree diagram [RFC8340] for the "ietf-http-
   server" module.














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   module: ietf-http-server

     grouping http-server-grouping
       +-- server-name?             string
       +-- protocol-versions
       |  +-- protocol-version*   enumeration
       +-- client-authentication!
          +-- (required-or-optional)
          |  +--:(required)
          |  |  +-- required?                        empty
          |  +--:(optional)
          |     +-- optional?                        empty
          +-- (local-or-external)
             +--:(local) {local-client-auth-supported}?
             |  +-- users
             |     +-- user* [user-id]
             |        +-- user-id?       string
             |        +-- (auth-type)?
             |           +--:(basic)
             |              +-- basic {basic-auth}?
             |                 +-- user-id?    string
             |                 +-- password?   ianach:crypt-hash
             +--:(external) {external-client-auth-supported}?
                +-- client-auth-defined-elsewhere?   empty

4.2.  Example Usage

   This section presents an example showing the http-server-grouping
   populated with some data.

   <http-server xmlns="urn:ietf:params:xml:ns:yang:ietf-http-server">
     <server-name>foo.example.com</server-name>
     <protocol-versions>
       <protocol-version>HTTP/1.1</protocol-version>
       <protocol-version>HTTP/2.0</protocol-version>
     </protocol-versions>
     <client-authentication>
       <required/>
       <client-auth-defined-elsewhere/>
     </client-authentication>
   </http-server>

4.3.  YANG Module

   This YANG module has normative references to [RFC6991].

   <CODE BEGINS> file "ietf-http-server@2019-11-02.yang"




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   module ietf-http-server {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-http-server";
     prefix https;

     import iana-crypt-hash {
       prefix ianach;
       reference
         "RFC 7317: A YANG Data Model for System Management";
     }

     import ietf-netconf-acm {
       prefix nacm;
       reference
         "RFC 8341: Network Configuration Access Control Model";
     }

     organization
       "IETF NETCONF (Network Configuration) Working Group";

     contact
       "WG Web:   <http://datatracker.ietf.org/wg/netconf/>
        WG List:  <mailto:netconf@ietf.org>
        Author:   Kent Watsen <mailto:kent+ietf@watsen.net>";

     description
       "This module defines reusable groupings for HTTP servers that
        can be used as a basis for specific HTTP server 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



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        capitals, as shown here.";

     revision 2019-11-02 {
       description
         "Initial version";
       reference
         "RFC XXXX: YANG Groupings for HTTP Clients and HTTP Servers";
     }

     // Features

     feature local-client-auth-supported {
       description
         "Indicates that the HTTP server supports local configuration
          of client credentials.";
     }

     feature external-client-auth-supported {
       description
         "Indicates that the HTTP server supports external configuration
          of client credentials.";
     }

     feature basic-auth {
       description
         "The 'basic-auth' feature indicates that the server
          may be configured authenticate users using the 'basic'
          HTTP authentication scheme.";
       reference
         "RFC 7617: The 'Basic' HTTP Authentication Scheme";
     }


     // Groupings

     grouping http-server-grouping {
       description
         "A reusable grouping for configuring an HTTP 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
          'http-server-parameters').  This model purposely does
          not do this itself so as to provide maximum flexibility
          to consuming models.";




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       leaf server-name {
         nacm:default-deny-write;
         type string;
         description
           "The value of the 'Server' header field.  If not set, then
            underlying software's default value is used.  Set to the
            empty string to disable.";
       }

       container protocol-versions {
         nacm:default-deny-write;
         description
           "A list of HTTP protocol versions supported by this
            server.";
         leaf-list protocol-version {
           type enumeration {
             enum "HTTP/1.0" {
               description
                 "The server supports the 'HTTP/1.0' protocol.";
             }
             enum "HTTP/1.1" {
               description
                 "The server supports the 'HTTP/1.1' protocol.";
             }
             enum "HTTP/2.0" {
               description
                 "The server supports the 'HTTP/2.0' protocol.";
             }
           }
           description
             "An HTTP protocol version supported by this server.";
         }
       }

       container client-authentication {
         nacm:default-deny-write;
         presence
           "Indicates that HTTP based client authentication is
            supported (i.e., the server will request that the
            HTTP client send authenticate when needed).  This
            is needed as some HTTP-based protocols may only
            support, e.g., TLS-level client authentication.";
         description
           "Specifies if HTTP client authentication is required or
            optional, and specifies if the credentials needed to
            authenticate the HTTP client are configured locally
            or externally.";
         choice required-or-optional {



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           mandatory true;  // or default to 'required' ?
           description
             "Indicates if HTTP-level client authentication is required
              or optional.  This is necessary for some protocols (e.g.,
              RESTCONF) that may optionally authenticate a client via
              TLS-level authentication, HTTP-level authentication, or
              both simultaneously).";
            leaf required {
              type empty;
              description
                "Indicates that HTTP-level client authentication is
                 required to access protected resources.";
            }
            leaf optional {
              type empty;
              description
                "Indicates that HTTP-level client authentication is
                 optional to access protected resources.";
            }
         }
         choice local-or-external {
           mandatory true;
           description
             "Indicates if the client credentials are configured
              locally or externally.  The need to support external
              configuration for client authentication stems from
              the desire to support consuming data models that
              prefer to place client authentication with client
              definitions, rather then in a data model principally
              concerned with configuring the transport.";
           case local {
             if-feature "local-client-auth-supported";
             description
               "Client credentials are configured locally.";
             container users {
               description
                 "A list of locally configured users.";
               list user {
                 key user-id;
                 description
                   "The list of local users configured on this device.";
                 leaf user-id {
                   type string;
                   description
                     "The user-id for the authenticating client.";
                 }
                 choice auth-type {
                   description



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                     "The authentication type.";
                   container basic {
                     if-feature "basic-auth";
                     leaf user-id {
                       type string;
                       description
                         "The user-id for the authenticating client.";
                     }
                     leaf password {
                       nacm:default-deny-write;
                       type ianach:crypt-hash;
                       description
                         "The password for the authenticating client.";
                     }
                     description
                       "The 'basic' HTTP scheme credentials.";
                     reference
                       "RFC 7617:
                         The 'Basic' HTTP Authentication Scheme";
                   }
                 }
               }
             }
           }
           case external {
             if-feature "external-client-auth-supported";
             description
               "Client credentials are configured externally.";
             leaf client-auth-defined-elsewhere {
               type empty;
               description
                 "Indicates that credentials needed to authenticate
                  clients are configured elsewhere.";
             }
           }
         } // choice local-or-external
       } // container client-authentication

     }
   }

   <CODE ENDS>

5.  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-



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   implement secure transport layers (e.g., SSH, HTTP) 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:

      FIXME: (pending - TBD)

   Some of the readable data nodes in the YANG modules 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:

      FIXME: (pending client auth params?)

   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:

      The modules defined in this document do not define any 'RPC' or
   'action' statements.

6.  IANA Considerations

6.1.  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:







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      URI: urn:ietf:params:xml:ns:yang:ietf-http-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-http-server
      Registrant Contact: The NETCONF WG of the IETF.
      XML: N/A, the requested URI is an XML namespace.

6.2.  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-http-client
      namespace:    urn:ietf:params:xml:ns:yang:ietf-http-client
      prefix:       httpc
      reference:    RFC XXXX

      name:         ietf-http-server
      namespace:    urn:ietf:params:xml:ns:yang:ietf-http-server
      prefix:       https
      reference:    RFC XXXX

7.  References

7.1.  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,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://www.rfc-editor.org/info/rfc6020>.

   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <https://www.rfc-editor.org/info/rfc6991>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.






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   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.

7.2.  Informative References

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [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,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

Author's Address

   Kent Watsen
   Watsen Networks

   EMail: kent+ietf@watsen.net

















Watsen                     Expires May 4, 2020                 [Page 16]