| NETCONF Working Group | K. Watsen |
| Internet-Draft | Juniper Networks |
| Intended status: Standards Track | G. Wu |
| Expires: May 7, 2017 | Cisco Networks |
| J. Schoenwaelder | |
| Jacobs University Bremen | |
| November 3, 2016 |
NETCONF Client and Server Models
draft-ietf-netconf-netconf-client-server-01
This document defines two YANG modules, one module to configure a NETCONF client and the other module to configure a NETCONF server. Both modules support both the SSH and TLS transport protocols, and support both standard NETCONF and NETCONF Call Home connections.
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:
Artwork in this document contains shorthand references to drafts in progress. Please apply the following replacements:
Artwork in this document contains placeholder values for the date of publication of this draft. Please apply the following replacement:
The following two Appendix sections are to be removed prior to publication:
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 May 7, 2017.
Copyright (c) 2016 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.
This document defines two YANG [RFC6020] modules, one module to configure a NETCONF client and the other module to configure a NETCONF server. Both modules support both the SSH and TLS transport protocols, and support both standard NETCONF and NETCONF Call Home connections.
NETCONF is defined by [RFC6241]. SSH is defined by [RFC4252], [RFC4253], and [RFC4254]. TLS is defined by [RFC5246]. NETCONF Call Home is defined by [draft-ietf-netconf-call-home]).
The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].
A simplified graphical representation of the data models is used in this document. The meaning of the symbols in these diagrams is as follows:
The NETCONF 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 both the SSH and TLS transport protocols, using the SSH client and TLS client groupings defined in [draft-ietf-netconf-ssh-client-server] and [draft-ietf-netconf-tls-client-server] respectively.
All private keys and trusted certificates are held in the keystore model defined in [draft-ietf-netconf-keystore].
YANG feature statements are used to enable implementations to advertise which parts of the model the NETCONF client supports.
Note: all lines are folded at column 71 with no '\' character.
module: ietf-netconf-client
+--rw netconf-client
+--rw initiate {initiate}?
| +--rw netconf-server* [name]
| +--rw name string
| +--rw (transport)
| +--:(ssh) {ssh-initiate}?
| +--rw ssh
| +--rw address inet:host
| +--rw port? inet:port-number
| +--rw server-auth
| | +--rw trusted-ssh-host-keys? -> /ks:keystore
/trusted-ssh-host-keys/name
| | +--rw trusted-ca-certs? -> /ks:keystore
/trusted-certificates/name {ssh-x509-certs}?
| | +--rw trusted-server-certs? -> /ks:keystore
/trusted-certificates/name
| +--rw client-auth
| +--rw matches* [name]
| +--rw name string
| +--rw match* [name]
| | +--rw name string
| | +--rw trusted-ssh-host-keys? -> /ks:ke
ystore/trusted-ssh-host-keys/name
| | +--rw trusted-ca-certs? -> /ks:ke
ystore/trusted-certificates/name
| | +--rw trusted-server-certs? -> /ks:ke
ystore/trusted-certificates/name
| +--rw user-auth-credentials? -> /ks:keyst
ore/user-auth-credentials/user-auth-credential/username
+--rw listen {listen}?
+--rw max-sessions? uint16
+--rw idle-timeout? uint16
+--rw endpoint* [name]
+--rw name string
+--rw (transport)
+--:(ssh) {ssh-listen}?
+--rw ssh
+--rw address? inet:ip-address
+--rw port? inet:port-number
+--rw server-auth
| +--rw trusted-ssh-host-keys? -> /ks:keystore
/trusted-ssh-host-keys/name
| +--rw trusted-ca-certs? -> /ks:keystore
/trusted-certificates/name {ssh-x509-certs}?
| +--rw trusted-server-certs? -> /ks:keystore
/trusted-certificates/name
+--rw client-auth
+--rw matches* [name]
+--rw name string
+--rw match* [name]
| +--rw name string
| +--rw trusted-ssh-host-keys? -> /ks:ke
ystore/trusted-ssh-host-keys/name
| +--rw trusted-ca-certs? -> /ks:ke
ystore/trusted-certificates/name
| +--rw trusted-server-certs? -> /ks:ke
ystore/trusted-certificates/name
+--rw user-auth-credentials? -> /ks:keyst
ore/user-auth-credentials/user-auth-credential/username
The following example illustrates configuring a NETCONF client to initiate connections, using both the SSH and TLS transport protocols, as well as listening for call-home connections, again using both the SSH and TLS transport protocols.
This example is consistent with the examples presented in Section 2.2 of [draft-ietf-netconf-keystore].
<netconf-client
xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-client">
<!-- NETCONF servers to initiate NETCONF connections to -->
<initiate>
<netconf-server>
<name>corp-fw1</name>
<ssh>
<address>corp-fw1.example.com</address>
<server-auth>
<trusted-server-certs>
deployment-specific-ca-certs
</trusted-server-certs>
</server-auth>
<client-auth>
<matches>
<match>
<trusted-ca-certs>
deployment-specific-ca-certs
</trusted-ca-certs>
</match>
<user-auth-credentials>Bob</user-auth-credentials>
</matches>
</client-auth>
</ssh>
</netconf-server>
</initiate>
<!-- endpoints to listen for NETCONF Call Home connections on -->
<listen>
<endpoint>
<name>Intranet-facing listener</name>
<ssh>
<address>11.22.33.44</address>
<server-auth>
<trusted-ca-certs>
deployment-specific-ca-certs
</trusted-ca-certs>
<trusted-server-certs>
explicitly-trusted-server-certs
</trusted-server-certs>
<trusted-ssh-host-keys>
explicitly-trusted-ssh-host-keys
</trusted-ssh-host-keys>
</server-auth>
<client-auth>
<matches>
<match>
<trusted-ca-certs>
deployment-specific-ca-certs
</trusted-ca-certs>
</match>
<user-auth-credentials>admin</user-auth-credentials>
</matches>
<matches>
<match>
<trusted-ca-certs>
explicitly-trusted-server-certs
</trusted-ca-certs>
</match>
<user-auth-credentials>admin</user-auth-credentials>
</matches>
<matches>
<match>
<trusted-ca-certs>
explicitly-trusted-ssh-host-keys
</trusted-ca-certs>
</match>
<user-auth-credentials>admin</user-auth-credentials>
</matches>
</client-auth>
</ssh>
</endpoint>
</listen>
</netconf-client>
This YANG module imports YANG types from [RFC6991] and [RFC7407].
<CODE BEGINS> file "ietf-netconf-client@2016-11-02.yang"
module ietf-netconf-client {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-client";
prefix "ncc";
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-ssh-client {
prefix ss;
revision-date 2016-11-02; // stable grouping definitions
reference
"RFC YYYY: SSH Client and Server Models";
}
// import ietf-tls-client {
// prefix ts;
// revision-date 2016-11-02; // stable grouping definitions
// reference
// "RFC ZZZZ: TLS Client and Server Models";
// }
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
WG Chair: Mehmet Ersue
<mailto:mehmet.ersue@nsn.com>
WG Chair: Mahesh Jethanandani
<mailto:mjethanandani@gmail.com>
Author: Kent Watsen
<mailto:kwatsen@juniper.net>
Author: Gary Wu
<mailto:garywu@cisco.com>";
description
"This module contains a collection of YANG definitions for
configuring NETCONF servers.
Copyright (c) 2014 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD
License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
revision "2016-11-02" {
description
"Initial version";
reference
"RFC XXXX: NETCONF Client and Server Models";
}
// Features
feature initiate {
description
"The 'initiate' feature indicates that the NETCONF client
supports initiating NETCONF connections to NETCONF servers
using at least one transport (e.g., SSH, TLS, etc.).";
}
feature ssh-initiate {
description
"The ‘ssh-initiate’ feature indicates that the NETCONF client
supports initiating SSH connections to NETCONF servers.";
reference
"RFC 6242: Using the NETCONF Protocol over Secure Shell (SSH)";
}
feature tls-initiate {
description
"The ‘tls-initiate’ feature indicates that the NETCONF client
supports initiating TLS connections to NETCONF servers.";
reference
"RFC 7589: Using the NETCONF Protocol over Transport
Layer Security (TLS) with Mutual X.509
Authentication";
}
feature listen {
description
"The 'listen' feature indicates that the NETCONF client
supports opening a port to accept NETCONF server call
home connections using at least one transport (e.g.,
SSH, TLS, etc.).";
}
feature ssh-listen {
description
"The ‘ssh-listen’ feature indicates that the NETCONF client
supports opening a port to listen for incoming NETCONF
server call-home SSH connections.";
reference
"RFC AAAA: NETCONF Call Home and RESTCONF Call Home";
}
feature tls-listen {
description
"The ‘tls-listen’ feature indicates that the NETCONF client
supports opening a port to listen for incoming NETCONF
server call-home TLS connections.";
reference
"RFC AAAA: NETCONF Call Home and RESTCONF Call Home";
}
container netconf-client {
description
"Top-level container for NETCONF client configuration.";
container initiate {
if-feature initiate;
description
"Configures client intiating underlying TCP connections.";
list netconf-server {
key name;
description
"List of NETCONF servers the NETCONF client is to initiate
connections to.";
leaf name {
type string;
description
"An arbitrary name for the NETCONF server.";
}
choice transport {
mandatory true;
description
"Selects between available transports.";
case ssh {
if-feature ssh-initiate;
container ssh {
description
"Specifies SSH-specific transport configuration.";
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 NETCONF
client will process the IP addresses as if they
had been explicitly configured in place of the
hostname.";
}
leaf port {
type inet:port-number;
default 830;
description
"The IP port for this endpoint. The NETCONF client
will use the IANA-assigned well-known port if no
value is specified.";
}
uses ss:initiating-ssh-client-grouping;
}
}
/*
case tls {
if-feature tls-initiate;
container tls {
description
"Specifies TLS-specific transport configuration.";
uses endpoints-container {
refine endpoints/endpoint/port {
default 6513;
}
}
uses ts:listening-tls-client-grouping {
augment "client-auth" {
description
"Augments in the cert-to-name structure.";
uses cert-maps-grouping;
}
}
}
}
*/
}
}
} // 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 NETCONF
session may remain idle. A NETCONF 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 NETCONF connections on.";
leaf name {
type string;
description
"An arbitrary name for the NETCONF listen endpoint.";
}
choice transport {
mandatory true;
description
"Selects between available transports.";
case ssh {
if-feature ssh-listen;
container ssh {
description
"SSH-specific listening configuration for inbound
connections.";
uses ss:listening-ssh-client-grouping {
refine port {
default 4334;
}
}
}
}
/*
case tls {
if-feature tls-listen;
container tls {
description
"TLS-specific listening configuration for inbound
connections.";
uses ts:listening-tls-client-grouping {
refine port {
default 4335;
}
augment "client-auth" {
description
"Augments in the cert-to-name structure.";
uses cert-maps-grouping;
}
}
}
}
*/
}
}
} // end listen
}
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 NETCONF
server to map the NETCONF client's presented X.509
certificate to a NETCONF username. If no matching and
valid cert-to-name list entry can be found, then the
NETCONF server MUST close the connection, and MUST NOT
accept NETCONF messages over it.";
reference
"RFC WWWW: NETCONF over TLS, Section 7";
}
}
}
<CODE ENDS>
The NETCONF server model presented in this section supports servers both listening for connections as well as initiating call-home connections.
This model also supports both the SSH and TLS transport protocols, using the SSH server and TLS server groupings defined in [draft-ietf-netconf-ssh-client-server] and [draft-ietf-netconf-tls-client-server] respectively.
All private keys and trusted certificates are held in the keystore model defined in [draft-ietf-netconf-keystore].
YANG feature statements are used to enable implementations to advertise which parts of the model the NETCONF server supports.
Note: all lines are folded at column 71 with no '\' character.
module: ietf-netconf-server
+--rw netconf-server
+--rw session-options
| +--rw hello-timeout? uint16
+--rw listen {listen}?
| +--rw max-sessions? uint16
| +--rw idle-timeout? uint16
| +--rw endpoint* [name]
| +--rw name string
| +--rw (transport)
| +--:(ssh) {ssh-listen}?
| | +--rw ssh
| | +--rw address? inet:ip-address
| | +--rw port? inet:port-number
| | +--rw host-keys
| | | +--rw host-key* [name]
| | | +--rw name string
| | | +--rw (host-key-type)
| | | +--:(public-key)
| | | | +--rw public-key? -> /ks:keystore/
private-keys/private-key/name
| | | +--:(certificate)
| | | +--rw certificate? -> /ks:keystore/
private-keys/private-key/certificate-chains/certificate-chain/name {ssh
-x509-certs}?
| | +--rw client-cert-auth {ssh-x509-certs}?
| | +--rw trusted-ca-certs? -> /ks:keystore/
trusted-certificates/name
| | +--rw trusted-client-certs? -> /ks:keystore/
trusted-certificates/name
| +--:(tls) {tls-listen}?
| +--rw tls
| +--rw address? inet:ip-address
| +--rw port? inet:port-number
| +--rw certificates
| | +--rw certificate* [name]
| | +--rw name -> /ks:keystore/private-keys/
private-key/certificate-chains/certificate-chain/name
| +--rw client-auth
| +--rw trusted-ca-certs? -> /ks:keystore/
trusted-certificates/name
| +--rw trusted-client-certs? -> /ks:keystore/
trusted-certificates/name
| +--rw cert-maps
| +--rw cert-to-name* [id]
| +--rw id uint32
| +--rw fingerprint x509c2n:tls-fingerp
rint
| +--rw map-type identityref
| +--rw name string
+--rw call-home {call-home}?
+--rw netconf-client* [name]
+--rw name string
+--rw (transport)
| +--:(ssh) {ssh-call-home}?
| | +--rw ssh
| | +--rw endpoints
| | | +--rw endpoint* [name]
| | | +--rw name string
| | | +--rw address inet:host
| | | +--rw port? inet:port-number
| | +--rw host-keys
| | | +--rw host-key* [name]
| | | +--rw name string
| | | +--rw (host-key-type)
| | | +--:(public-key)
| | | | +--rw public-key? -> /ks:keystore/
private-keys/private-key/name
| | | +--:(certificate)
| | | +--rw certificate? -> /ks:keystore/
private-keys/private-key/certificate-chains/certificate-chain/name {ssh
-x509-certs}?
| | +--rw client-cert-auth {ssh-x509-certs}?
| | +--rw trusted-ca-certs? -> /ks:keystore/
trusted-certificates/name
| | +--rw trusted-client-certs? -> /ks:keystore/
trusted-certificates/name
| +--:(tls) {tls-call-home}?
| +--rw tls
| +--rw endpoints
| | +--rw endpoint* [name]
| | +--rw name string
| | +--rw address inet:host
| | +--rw port? inet:port-number
| +--rw certificates
| | +--rw certificate* [name]
| | +--rw name -> /ks:keystore/private-keys/
private-key/certificate-chains/certificate-chain/name
| +--rw client-auth
| +--rw trusted-ca-certs? -> /ks:keystore/
trusted-certificates/name
| +--rw trusted-client-certs? -> /ks:keystore/
trusted-certificates/name
| +--rw cert-maps
| +--rw cert-to-name* [id]
| +--rw id uint32
| +--rw fingerprint x509c2n:tls-fingerp
rint
| +--rw map-type identityref
| +--rw name string
+--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
The following example illustrates configuring a NETCONF server to listen for NETCONF client connections using both the SSH and TLS transport protocols, as well as configuring call-home to two NETCONF clients, one using SSH and the other using TLS.
This example is consistent with the examples presented in Section 2.2 of [draft-ietf-netconf-keystore].
<netconf-server
xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-server">
<listen>
<!-- listening for SSH connections -->
<endpoint>
<name>netconf/ssh</name>
<ssh>
<address>11.22.33.44</address>
<host-keys>
<host-key>
<public-key>my-rsa-key</public-key>
</host-key>
<host-key>
<certificate>TPM key</certificate>
</host-key>
</host-keys>
<client-cert-auth>
<trusted-ca-certs>
deployment-specific-ca-certs
</trusted-ca-certs>
<trusted-client-certs>
explicitly-trusted-client-certs
</trusted-client-certs>
</client-cert-auth>
</ssh>
</endpoint>
<!-- listening for TLS connections -->
<endpoint>
<name>netconf/tls</name>
<tls>
<address>11.22.33.44</address>
<certificates>
<certificate>ex-key-sect571r1-cert</certificate>
</certificates>
<client-auth>
<trusted-ca-certs>
deployment-specific-ca-certs
</trusted-ca-certs>
<trusted-client-certs>
explicitly-trusted-client-certs
</trusted-client-certs>
<cert-maps>
<cert-to-name>
<id>1</id>
<fingerprint>11:0A:05:11:00</fingerprint>
<map-type>x509c2n:san-any</map-type>
</cert-to-name>
<cert-to-name>
<id>2</id>
<fingerprint>B3:4F:A1:8C:54</fingerprint>
<map-type>x509c2n:specified</map-type>
<name>scooby-doo</name>
</cert-to-name>
</cert-maps>
</client-auth>
</tls>
</endpoint>
</listen>
<call-home>
<!-- calling home to an SSH-based NETCONF client -->
<netconf-client>
<name>config-mgr</name>
<ssh>
<endpoints>
<endpoint>
<name>east-data-center</name>
<address>11.22.33.44</address>
</endpoint>
<endpoint>
<name>west-data-center</name>
<address>55.66.77.88</address>
</endpoint>
</endpoints>
<host-keys>
<host-key>
<certificate>TPM key</certificate>
</host-key>
</host-keys>
<client-cert-auth>
<trusted-ca-certs>
deployment-specific-ca-certs
</trusted-ca-certs>
<trusted-client-certs>
explicitly-trusted-client-certs
</trusted-client-certs>
</client-cert-auth>
</ssh>
<connection-type>
<periodic>
<idle-timeout>300</idle-timeout>
<reconnect-timeout>60</reconnect-timeout>
</periodic>
</connection-type>
<reconnect-strategy>
<start-with>last-connected</start-with>
<max-attempts>3</max-attempts>
</reconnect-strategy>
</netconf-client>
<!-- calling home to a TLS-based NETCONF client -->
<netconf-client>
<name>event-correlator</name>
<tls>
<endpoints>
<endpoint>
<name>east-data-center</name>
<address>22.33.44.55</address>
</endpoint>
<endpoint>
<name>west-data-center</name>
<address>33.44.55.66</address>
</endpoint>
</endpoints>
<certificates>
<certificate>ex-key-sect571r1-cert</certificate>
</certificates>
<client-auth>
<trusted-ca-certs>
deployment-specific-ca-certs
</trusted-ca-certs>
<trusted-client-certs>
explicitly-trusted-client-certs
</trusted-client-certs>
<cert-maps>
<cert-to-name>
<id>1</id>
<fingerprint>11:0A:05:11:00</fingerprint>
<map-type>x509c2n:san-any</map-type>
</cert-to-name>
<cert-to-name>
<id>2</id>
<fingerprint>B3:4F:A1:8C:54</fingerprint>
<map-type>x509c2n:specified</map-type>
<name>scooby-doo</name>
</cert-to-name>
</cert-maps>
</client-auth>
</tls>
<connection-type>
<persistent>
<idle-timeout>300</idle-timeout>
<keep-alives>
<max-wait>30</max-wait>
<max-attempts>3</max-attempts>
</keep-alives>
</persistent>
</connection-type>
<reconnect-strategy>
<start-with>first-listed</start-with>
<max-attempts>3</max-attempts>
</reconnect-strategy>
</netconf-client>
</call-home>
</netconf-server>
This YANG module imports YANG types from [RFC6991] and [RFC7407].
<CODE BEGINS> file "ietf-netconf-server@2016-11-02.yang"
module ietf-netconf-server {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-server";
prefix "ncs";
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-ssh-server {
prefix ss;
revision-date 2016-11-02; // stable grouping definitions
reference
"RFC YYYY: SSH Client and Server Models";
}
import ietf-tls-server {
prefix ts;
revision-date 2016-11-02; // stable grouping definitions
reference
"RFC ZZZZ: TLS Client and Server Models";
}
organization
"IETF NETCONF (Network Configuration) Working Group";
contact
"WG Web: <http://tools.ietf.org/wg/netconf/>
WG List: <mailto:netconf@ietf.org>
WG Chair: Mehmet Ersue
<mailto:mehmet.ersue@nsn.com>
WG Chair: Mahesh Jethanandani
<mailto:mjethanandani@gmail.com>
Editor: Kent Watsen
<mailto:kwatsen@juniper.net>";
description
"This module contains a collection of YANG definitions for
configuring NETCONF servers.
Copyright (c) 2014 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD
License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
revision "2016-11-02" {
description
"Initial version";
reference
"RFC XXXX: NETCONF Client and Server Models";
}
// Features
feature listen {
description
"The 'listen' feature indicates that the NETCONF server
supports opening a port to accept NETCONF client connections
using at least one transport (e.g., SSH, TLS, etc.).";
}
feature ssh-listen {
description
"The 'ssh-listen' feature indicates that the NETCONF server
supports opening a port to accept NETCONF over SSH
client connections.";
reference
"RFC 6242: Using the NETCONF Protocol over Secure Shell (SSH)";
}
feature tls-listen {
description
"The 'tls-listen' feature indicates that the NETCONF server
supports opening a port to accept NETCONF over TLS
client connections.";
reference
"RFC 7589: Using the NETCONF Protocol over Transport
Layer Security (TLS) with Mutual X.509
Authentication";
}
feature call-home {
description
"The 'call-home' feature indicates that the NETCONF server
supports initiating NETCONF call home connections to NETCONF
clients using at least one transport (e.g., SSH, TLS, etc.).";
reference
"RFC YYYY: NETCONF Call Home and RESTCONF Call Home";
}
feature ssh-call-home {
description
"The 'ssh-call-home' feature indicates that the NETCONF
server supports initiating a NETCONF over SSH call
home connection to NETCONF clients.";
reference
"RFC YYYY: NETCONF Call Home and RESTCONF Call Home";
}
feature tls-call-home {
description
"The 'tls-call-home' feature indicates that the NETCONF
server supports initiating a NETCONF over TLS call
home connection to NETCONF clients.";
reference
"RFC YYYY: NETCONF Call Home and RESTCONF Call Home";
}
// top-level container (groupings below)
container netconf-server {
description
"Top-level container for NETCONF server configuration.";
container session-options { // SHOULD WE REMOVE THIS ALTOGETHER?
description
"NETCONF session options, independent of transport
or connection strategy.";
leaf hello-timeout {
type uint16;
units "seconds";
default 600;
description
"Specifies the maximum number of seconds that a SSH/TLS
connection may wait for a hello message to be received.
A connection will be dropped if no hello message is
received before this number of seconds elapses. If set
to zero, then the server will wait forever for a hello
message.";
}
}
container listen {
if-feature listen;
description
"Configures listen behavior";
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 NETCONF
session may remain idle. A NETCONF 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 NETCONF connections on.";
leaf name {
type string;
description
"An arbitrary name for the NETCONF listen endpoint.";
}
choice transport {
mandatory true;
description
"Selects between available transports.";
case ssh {
if-feature ssh-listen;
container ssh {
description
"SSH-specific listening configuration for inbound
connections.";
uses ss:listening-ssh-server-grouping {
refine port {
default 830;
}
}
}
}
case tls {
if-feature tls-listen;
container tls {
description
"TLS-specific listening configuration for inbound
connections.";
uses ts:listening-tls-server-grouping {
refine port {
default 6513;
}
augment "client-auth" {
description
"Augments in the cert-to-name structure.";
uses cert-maps-grouping;
}
}
}
}
}
}
}
container call-home {
if-feature call-home;
description
"Configures call-home behavior";
list netconf-client {
key name;
description
"List of NETCONF clients the NETCONF server is to initiate
call-home connections to.";
leaf name {
type string;
description
"An arbitrary name for the remote NETCONF client.";
}
choice transport {
mandatory true;
description
"Selects between available transports.";
case ssh {
if-feature ssh-call-home;
container ssh {
description
"Specifies SSH-specific call-home transport
configuration.";
uses endpoints-container {
refine endpoints/endpoint/port {
default 4334;
}
}
uses ss:non-listening-ssh-server-grouping;
}
}
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 4335;
}
}
uses ts:non-listening-tls-server-grouping {
augment "client-auth" {
description
"Augments in the cert-to-name structure.";
uses cert-maps-grouping;
}
}
}
}
}
container connection-type {
description
"Indicates the 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 NETCONF
client. If the connection goes down, immediately
start trying to reconnect to it, using the
reconnection strategy.
This connection type minimizes any NETCONF client
to NETCONF server data-transfer delay, albeit at
the expense of holding resources longer.";
leaf idle-timeout {
type uint32;
units "seconds";
default 86400; // one day;
description
"Specifies the maximum number of seconds that a
a NETCONF session may remain idle. A NETCONF
session will be dropped if it is idle for an
interval longer than this number of seconds.
If set to zero, then the server will never drop
a session because it is idle. Sessions that
have a notification subscription active are
never dropped.";
}
container keep-alives {
description
"Configures the keep-alive policy, to proactively
test the aliveness of the SSH/TLS client. An
unresponsive SSH/TLS client will be dropped after
approximately max-attempts * max-wait seconds.";
reference
"RFC YYYY: NETCONF Call Home and RESTCONF Call
Home, Section 3.1, item S6";
leaf max-wait {
type uint16 {
range "1..max";
}
units seconds;
default 30;
description
"Sets the amount of time in seconds after which
if no data has been received from the SSH/TLS
client, a SSH/TLS-level message will be sent
to test the aliveness of the SSH/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 SSH/TLS client before assuming the SSH/TLS
client is no longer alive.";
}
}
}
}
case periodic-connection {
container periodic {
presence true;
description
"Periodically connect to the NETCONF client, so that
the NETCONF client may deliver messages pending for
the NETCONF server. The NETCONF client must close
the connection when it is ready to release it. Once
the connection has been closed, the NETCONF server
will restart its timer until the next connection.";
leaf idle-timeout {
type uint16;
units "seconds";
default 300; // five minutes
description
"Specifies the maximum number of seconds that a
a NETCONF session may remain idle. A NETCONF
session will be dropped if it is idle for an
interval longer than this number of seconds.
If set to zero, then the server will never drop
a session because it is idle. Sessions that
have a notification subscription active are
never dropped.";
}
leaf reconnect_timeout {
type uint16 {
range "1..max";
}
units minutes;
default 60;
description
"Sets the maximum amount of unconnected time the
NETCONF server will wait before re-establishing
a connection to the NETCONF client. The NETCONF
server may initiate a connection before this
time if desired (e.g., to deliver an event
notification message).";
}
}
}
}
}
container reconnect-strategy {
description
"The reconnection strategy directs how a NETCONF server
reconnects to a NETCONF client, after discovering its
connection to the client has dropped, even if due to a
reboot. The NETCONF 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. NETCONF
servers SHOULD be able to remember the last
endpoint connected to across reboots.";
}
}
default first-listed;
description
"Specifies which of the NETCONF client's endpoints the
NETCONF server should start with when trying to connect
to the NETCONF client.";
}
leaf max-attempts {
type uint8 {
range "1..max";
}
default 3;
description
"Specifies the number times the NETCONF 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 NETCONF
server to map the NETCONF client's presented X.509
certificate to a NETCONF username. If no matching and
valid cert-to-name list entry can be found, then the
NETCONF server MUST close the connection, and MUST NOT
accept NETCONF messages over it.";
reference
"RFC WWWW: NETCONF over TLS, Section 7";
}
}
grouping endpoints-container {
description
"This grouping is used by both the ssh and tls containers
for call-home configurations.";
container endpoints {
description
"Container for the list of endpoints.";
list endpoint {
key name;
min-elements 1;
ordered-by user;
description
"User-ordered list of endpoints for this NETCONF 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 NETCONF 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 NETCONF server will
use the IANA-assigned well-known port if no value is
specified.";
}
}
}
}
}
<CODE ENDS>
Editorial: this section is a hold over from before, previously called "Objectives". It was only written two support the "server" (not the "client"). The question is if it's better to add the missing "client" parts, or remove this section altogether.
The primary purpose of the YANG modules defined herein is to enable the configuration of the NETCONF client and servers. This scope includes the following objectives:
The YANG module should support all current NETCONF transports, namely NETCONF over SSH [RFC6242], NETCONF over TLS [RFC7589], and to be extensible to support future transports as necessary.
Because implementations may not support all transports, the modules should use YANG "feature" statements so that implementations can accurately advertise which transports are supported.
Servers may have a multiplicity of host-keys or server-certificates from which subsets may be selected for specific uses. For instance, a NETCONF server may want to use one set of SSH host-keys when listening on port 830, and a different set of SSH host-keys when calling home. The data models provided herein should enable configuration of which keys to use on a per-use basis.
When a certificate is used to authenticate a NETCONF client, there is a need to configure the server to know how to authenticate the certificates. The server should be able to authenticate the client's certificate either by using path-validation to a configured trust anchor or by matching the client-certificate to one previously configured.
When a client certificate is used for TLS client authentication, the NETCONF server must be able to derive a username from the authenticated certificate. Thus the modules defined herein should enable this mapping to be configured.
The NETCONF protocols were originally defined as having the server opening a port to listen for client connections. More recently the NETCONF working group defined support for call-home ([draft-ietf-netconf-call-home]), enabling the server to initiate the connection to the client. Thus the modules defined herein should enable configuration for both listening for connections and calling home. Because implementations may not support both listening for connections and calling home, YANG "feature" statements should be used so that implementation can accurately advertise the connection types it supports.
The following objectives only pertain to call home connections.
A NETCONF server may be managed by more than one NETCONF client. For instance, a deployment may have one client for provisioning and another for fault monitoring. Therefore, when it is desired for a server to initiate call home connections, it should be able to do so to more than one client.
A NETCONF client managing a NETCONF server may implement a high-availability strategy employing a multiplicity of active and/or passive endpoint. Therefore, when it is desired for a server to initiate call home connections, it should be able to connect to any of the client's endpoints.
Assuming a NETCONF client has more than one endpoint, then it becomes necessary to configure how a NETCONF server should reconnect to the client should it lose its connection to one the client's endpoints. For instance, the NETCONF server may start with first endpoint defined in a user-ordered list of endpoints or with the last endpoints it was connected to.
NETCONF clients may vary greatly on how frequently they need to interact with a NETCONF server, how responsive interactions need to be, and how many simultaneous connections they can support. Some clients may need a persistent connection to servers to optimize real-time interactions, while others prefer periodic interactions in order to minimize resource requirements. Therefore, when it is necessary for server to initiate connections, it should be configurable if the connection is persistent or periodic.
The reconnection strategy should apply to both persistent and periodic connections. How it applies to periodic connections becomes clear when considering that a periodic "connection" is a logical connection to a single server. That is, the periods of unconnectedness are intentional as opposed to due to external reasons. A periodic "connection" should always reconnect to the same server until it is no longer able to, at which time the reconnection strategy guides how to connect to another server.
If a persistent connection is desired, it is the responsibility of the connection initiator to actively test the "aliveness" of the connection. The connection initiator must immediately work to reestablish a persistent connection as soon as the connection is lost. How often the connection should be tested is driven by NETCONF client requirements, and therefore keep-alive settings should be configurable on a per-client basis.
If a periodic connection is desired, it is necessary for the NETCONF server to know how often it should connect. This frequency determines the maximum amount of time a NETCONF client may have to wait to send data to a server. A server may connect to a client before this interval expires if desired (e.g., to send data to a client).
A denial of service (DoS) attack MAY occur if the NETCONF server limits the maximum number of NETCONF sessions it will accept (i.e. the 'max-sessions' field in the ietf-netconf-server module is not zero) and either the "hello-timeout" or "idle-timeout" fields in ietf-netconf-server module have been set to indicate the NETCONF server should wait forever (i.e. set to zero).
This document registers two URIs in the IETF XML registry [RFC2119]. Following the format in [RFC3688], the following registrations are requested:
URI: urn:ietf:params:xml:ns:yang:ietf-netconf-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-netconf-server Registrant Contact: The NETCONF WG of the IETF. XML: N/A, the requested URI is an XML namespace.
This document registers two YANG modules in the YANG Module Names registry [RFC6020]. Following the format in [RFC6020], the the following registrations are requested:
name: ietf-netconf-client namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-client prefix: ncc reference: RFC XXXX name: ietf-netconf-server namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-server prefix: ncs reference: RFC XXXX
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, 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.
| [draft-ietf-netconf-keystore] | Watsen, K., "Keystore Model", Internet-Draft draft-ieft-netconf-keystore-00, 2016. |
| [draft-ietf-netconf-ssh-client-server] | Watsen, K., "SSH Client and Server Models", Internet-Draft draft-ieft-netconf-ssh-client-server-00, 2016. |
| [draft-ietf-netconf-tls-client-server] | Watsen, K., "TLS Client and Server Models", Internet-Draft draft-ieft-netconf-tls-client-server-00, 2016. |
| [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., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010. |
| [RFC6241] | Enns, R., Bjorklund, M., Schoenwaelder, J. and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011. |
| [RFC6242] | Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011. |
| [RFC6991] | Schoenwaelder, J., "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. |
| [RFC7589] | Badra, M., Luchuk, A. and J. Schoenwaelder, "Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication", RFC 7589, DOI 10.17487/RFC7589, June 2015. |
| [draft-ietf-netconf-call-home] | Watsen, K., "NETCONF Call Home and RESTCONF Call Home", Internet-Draft draft-ieft-netconf-call-home-17, 2015. |
| [RFC3688] | Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004. |
| [RFC4252] | Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252, January 2006. |
| [RFC4253] | Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253, January 2006. |
| [RFC4254] | Ylonen, T. and C. Lonvick, "The Secure Shell (SSH) Connection Protocol", RFC 4254, DOI 10.17487/RFC4254, January 2006. |
| [RFC5246] | Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, August 2008. |
Please see: https://github.com/netconf-wg/netconf-client-server/issues.