One document matched: draft-ietf-netconf-server-model-01.xml
<?xml version='1.0'?>
<!DOCTYPE rfc SYSTEM 'rfc2629.dtd'>
<?rfc toc="yes"?>
<?rfc symrefs="yes"?>
<?rfc compact="no"?>
<?rfc subcompact="no"?>
<?rfc strict="no"?>
<?rfc rfcedstyle="yes"?>
<rfc category="std"
ipr="trust200902"
docName="draft-ietf-netconf-server-model-01" >
<front>
<title abbrev="NETCONF Server Configuration Model">NETCONF Server Configuration Model</title>
<author initials="K.W." surname="Watsen" fullname="Kent Watsen">
<organization>Juniper Networks</organization>
<address>
<email>kwatsen@juniper.net</email>
</address>
</author>
<author initials="J.S." surname="Schoenwaelder" fullname="Juergen Schoenwaelder">
<organization>Jacobs University Bremen</organization>
<address>
<email>j.schoenwaelder@jacobs-university.de</email>
</address>
</author>
<date month="June" year="2014"/>
<area>Operations</area>
<workgroup>NETCONF Working Group</workgroup>
<keyword>netconf-server</keyword>
<abstract>
<t>This draft defines a NETCONF server configuration data model.
This data model enables configuration of the NETCONF service
itself, including which transports it supports, what ports
they listen on, whether they support device-initiated
connections, and associated parameters.</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t>This draft defines a NETCONF <xref target="RFC6241"/> server
configuration data model.
This data model enables configuration of the NETCONF service
itself, including which transports are supported, what ports
does the server listen on, whether call-home is supported, and
associated parameters.</t>
<section title="Terminology">
<t>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 <xref target="RFC2119"/>.</t>
</section>
<section title="Tree Diagrams">
<t>A simplified graphical representation of data models
is used in this document. The meaning of the symbols in
these diagrams is as follows:
<list style="symbols">
<t>Brackets "[" and "]" enclose list keys.</t>
<t>Abbreviations before data node names: "rw" means
configuration (read-write) and "ro" state data
(read-only).</t>
<t>Symbols after data node names: "?" means an optional
node, "!" means a presence container, and "*" denotes a
list and leaf-list.</t>
<t>Parentheses enclose choice and case nodes, and case
nodes are also marked with a colon (":").</t>
</list>
</t>
</section>
</section>
<section title="Objectives">
<t>The primary purpose of the YANG module defined herein is
to enable the configuration of the NETCONF service on the
device. This scope includes the following objectives:</t>
<section title="Support all NETCONF Transports">
<t>The YANG module should support all current NETCONF
transports, namely NETCONF over SSH <xref
target="RFC6242"/> and NETCONF over TLS <xref
target="I-D.ietf-netconf-rfc5539bis"/>, and be extensible
to support future transports as necessary.</t>
<t>Since implementations may not support all transports,
the module should use YANG "feature" statements
so that implementation can accurately advertise which
transports are supported.</t>
</section>
<section title="Align Transport-Specific Configurations">
<t>While each transport is unique in its protocol and
may have some distinct configurations, there remains
a significant overlap between them. Thus the YANG module
should use "grouping" statements so that the
common aspects can be configured similarly.</t>
</section>
<section title="Support both Listening for Connections and Call Home">
<t>NETCONF has always supported the server opening
a port to listen for client connections. More recently
the NETCONF working group defined support for call-home
(<xref target="I-D.ietf-netconf-rfc5539bis"/> and
<xref target="draft-ieft-netconf-reverse-ssh"/>). The
module should configure both listening for connections
and call-home.</t>
<t>Since implementations may not support both listening for
connections and call home, YANG "feature" statements
should be used so that implementation can accurately
advertise the connection types it supports.</t>
</section>
<section title="For Call Home Connections">
<t>The following objectives only pertain to call home
connections.</t>
<section title="Support More than One Application">
<t>A device may be managed by more than one northbound
application. For instance, a deployment may have one
application for provisioning and another for fault
monitoring. Therefore, when it is desired for a device
to initiate call home connections, it should be able to
do so for more than one application.</t>
</section>
<section title="Support Applications Having More than One Server">
<t>An application managing a device may implement a
high-availability strategy employing a multiplicity of
active and/or passive servers. Therefore, when it is
desired for a device to initiate call home connections,
it should be able to connect to any of the applications
servers.</t>
</section>
<section title="Support a Reconnection Strategy">
<t>Assuming an application has more than one server, then
it becomes necessary to configure how a device should
reconnect to the application should it lose its
connection to the application's servers.
Of primary interest is if the device should
start with first server defined in a user-ordered
list of servers or with the last server it was connected
to. Secondary settings might specify the frequency of
attempts and number of attempts per server. Therefore,
a reconnection strategy should be configurable.</t>
</section>
<section title="Support both Persistent and Periodic Connections">
<t>Applications may vary greatly on how frequently they
need to interact with a device, how responsive interactions
with devices need to be, and how many simultaneous connections
they can support. Some applications may need a persistent
connection to devices to optimize real-time interactions,
while others are satisfied with periodic interactions and
reduced resources required. Therefore, when it is necessary
for devices to initiate connections, the type of connection
desired should be configured.</t>
</section>
<section title="Reconnection Strategy for Periodic Connections">
<t>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.</t>
</section>
<section anchor="keepalives" title="Keep-Alives for Persistent Connections">
<t>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 applications requirements, and therefore
keep-alive settings should be configurable on a
per-application basis.</t>
</section>
<section title="Customizations for Periodic Connections">
<t>If a periodic connection is desired, it is necessary
for the device to know how often it should connect. This
delay essentially determines how long the
application might have to wait to send data to the device.
This setting does not constrain how often the
device must wait to send data to the application, as the
device should immediately connect to the application
whenever it has data to send to it.</t>
<t>A common communication pattern is that one data
transmission is many times closely followed by
another. For instance, if the device needs to send a
notification message, there's a high probability that
it will send another shortly thereafter. Likewise,
the application may have a sequence of pending messages
to send. Thus, it should be possible for a device to
hold a connection open until some amount of time of no
data being transmitted as transpired.</t>
</section>
</section>
</section>
<section title="Data Model">
<section title="Overview">
<t>To enable transports to configure listening on one
or more ports in a common way, this grouping is defined.
This grouping defines SSH and TLS specific containers, each
of which refines the default listening port appropriately.
Further, each of these transport specific containers use a
feature statement, enabling NETCONF servers to accurately
advertise what they support.</t>
<t>
<figure>
<artwork><![CDATA[
module: ietf-netconf-server
+--rw netconf-server
+--rw listen
+--rw ssh {ssh-listen}?
| +--rw (one-or-many)?
| +--:(one-port)
| | +--rw port? inet:port-number
| +--:(many-ports)
| +--rw interface* [address]
| +--rw address inet:host
| +--rw port? inet:port-number
+--rw tls {tls-listen}?
+--rw (one-or-many)?
+--:(one-port)
| +--rw port? inet:port-number
+--:(many-ports)
+--rw interface* [address]
+--rw address inet:host
+--rw port? inet:port-number
]]></artwork>
</figure>
</t>
<t>To enable transports to configure initiating connections
to remote applications in a common way, this grouping is
defined. This grouping configures a list of network-managers,
each with some transport-specific configuration augmented in.
Each of the transport specific containers use a feature
statement, enabling NETCONF servers to accurately advertise
what they support.</t>
<t>
<figure>
<artwork><![CDATA[
module: ietf-netconf-server
+--rw netconf-server
+--rw call-home
+--rw network-managers
+--rw network-manager* [name]
+--rw name string
+--rw description? string
+--rw endpoints
| +--rw endpoint* [address]
| +--rw address inet:host
| +--rw port? inet:port-number
+--rw transport
| +--rw ssh {ssh-call-home}?
| | +--rw host-keys
| | +--rw host-key* [name]
| | +--rw name string
| +--rw tls! {tls-call-home}?
+--rw connection-type
| +--rw (connection-type)?
| +--:(persistent-connection)
| | +--rw persistent
| | +--rw keep-alives
| | +--rw interval-secs? uint8
| | +--rw count-max? uint8
| +--:(periodic-connection)
| +--rw periodic
| +--rw timeout-mins? uint8
| +--rw linger-secs? uint8
+--rw reconnect-strategy
+--rw start-with? enumeration
+--rw interval-secs? uint8
+--rw count-max? uint8
]]></artwork>
</figure>
</t>
</section>
<section title="YANG Module">
<t>This YANG module imports YANG types from <xref
target="RFC6991"/>.</t>
<t>
<figure>
<!--<preamble>The YANG Module</preamble>-->
<artwork><![CDATA[
RFC Ed.: update the date below with the date of RFC publication
and remove this note.
<CODE BEGINS> file "ietf-netconf-server.@2014-05-16.yang"
module ietf-netconf-server {
namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-server";
prefix "ncserver";
import ietf-inet-types {
prefix inet; // RFC 6991
}
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: Bert Wijnen
<mailto:bertietf@bwijnen.net>
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.";
// RFC Ed.: replace XXXX with actual RFC number and
// remove this note
// RFC Ed.: please update the date to the date of publication
revision "2014-01-24" {
description
"Initial version";
reference
"RFC XXXX: NETCONF Server Configuration Model";
}
// Features
feature ssh {
description
"A NETCONF server implements this feature if it supports NETCONF
over Secure Shell (SSH).";
reference
"RFC 6242: Using the NETCONF Protocol over Secure Shell (SSH)";
}
feature ssh-listen {
description
"The ssh-listen feature indicates that the NETCONF server can
open a port to listen for incoming client connections.";
}
feature ssh-call-home {
description
"The ssh-call-home feature indicates that the NETCONF server can
connect to a client.";
reference
"RFC XXXX: Reverse Secure Shell (Reverse SSH)";
}
feature tls {
description
"A NETCONF server implements this feature if it supports NETCONF
over Transport Layer Security (TLS).";
reference
"RFC XXXX: NETCONF over Transport Layer Security (TLS)";
}
feature tls-listen {
description
"The tls-listen feature indicates that the NETCONF server can
open a port to listen for incoming client connections.";
}
feature tls-call-home {
description
"The tls-call-home feature indicates that the NETCONF server can
connect to a client.";
}
// Groupings
grouping one-or-many-config {
description
"Provides a choice of configuring one of more ports
to listen for incoming client connections.";
choice one-or-many {
default one-port;
case one-port {
leaf port {
type inet:port-number;
description
"The port number the NETCONF server listens on on all
interfaces.";
}
}
case many-ports {
list interface {
key "address";
leaf address {
type inet:host;
mandatory true;
description
"The local IP address of the interface to listen
on.";
}
leaf port {
type inet:port-number;
description
"The local port number on this interface the
NETCONF server listens on.";
}
}
}
}
}
grouping network-managers-config {
container network-managers {
description
"A list of network managers the device initates connections
to. The configuration for each network manager specifies
its details, including its endpoints, the type of
connection to maintain, and the reconnection strategy
to use.";
list network-manager {
key name;
leaf name {
type string {
length 1..64; // XXX why these limits?
}
mandatory true;
description
"An arbitrary name for the network manager the device
is connecting to.";
}
leaf description {
type string;
description
"An optional description for the network manager.";
}
container endpoints {
description
"An ordered listing of the network manager's
endpoints that the device should attempt connecting
to. Defining more than one enables the device to
support high-availability scenarios.";
list endpoint {
key address;
min-elements 1;
ordered-by user;
leaf address {
type inet:host;
mandatory true;
description
"The hostname or IP address of the endpoint.
If a hostname is provided and DNS resolves to
more than one IP address, the device SHOULD
try all of the ones it can based on how its
networking stack is configured (e.g. v4, v6,
dual-stack).";
}
leaf port {
type inet:port-number;
description
"The IP port for this endpoint. The device will use
the IANA-assigned well-known port if not specified.";
}
}
}
container transport {
}
container connection-type {
description
"Indicates the network manager's preference for how the
device's connection is maintained.";
choice connection-type {
default persistent-connection;
case persistent-connection {
container persistent {
description
"Maintain a persistent connection to the
network manager. If the connection goes down,
immediately start trying to reconnect to it,
using the reconnection strategy.
This connection type minimizes any
manager-to-device data-transfer delay,
albeit at the expense of holding resources
longer.";
container keep-alives {
leaf interval-secs {
type uint8;
units seconds;
default 15;
description
"Sets a timeout interval in seconds after which
if no data has been received from the manager's
endpoint, a message will be sent to request a
response from the endpoint. A value of '0'
indicates that no keep-alive messages should
be sent.";
}
leaf count-max {
type uint8;
default 3;
description
"Sets the number of keep-alive messages that may
be sent without receiving any data from the
manager's endpoint before assuming the endpoint
is no longer alive. If this threshold is
reached, the transport-level connection will be
disconnected (thus triggering the reconnection
strategy). The interval timer is reset after
each transmission, thus an unresponsive
endpoint will be disconnected after about
count-max * interval-secs seconds.";
}
}
}
}
case periodic-connection {
container periodic {
description
"Periodically connect to network manager, using the
reconnection strategy, so it can flush any pending
data it may be holding. This connection type
minimizes resources held open, albeit at the
expense of longer manager-to-device data-transfer
delay. Note that for device-to-manager data, the
data should be sent immediately, connecting to
network manager first if not already.";
leaf timeout-mins {
type uint8;
units minutes;
default 5;
description
"The maximum amount of unconnected time the
device will wait until establishing a
connection to the network manager again. The
device MAY establish a connection before this
time if it has data it needs to send to the
network manager. Note: this value differs from
the reconnection strategy's interval-secs
value.";
}
leaf linger-secs {
type uint8;
units seconds;
default 30;
description
"The amount of time the device should wait after
last receiving data from or sending data to the
network manager's endpoint before closing its
connection to it. This is an optimization to
prevent unnecessary connections.";
}
}
}
}
}
// XXX
// Should we have something smarter as the reconnect
// strategy, e.g. an exponential backoff?
container reconnect-strategy {
description
"The reconnection strategy guides how a device reconnects
to an network manager, after losing a connection to it,
even if due to a reboot. The device starts with the
specified endpoint, tries to connect to it count-max
times, waiting interval-secs between each connection
attempt, before trying the next endpoint in the list
(round robin).";
leaf start-with {
type enumeration {
enum first-listed { value 1; }
enum last-connected { value 2; }
}
default first-listed;
description
"Specifies which of the network manager's endpoints the
device should start with when trying to connect to
the network manager. If no previous connection has
ever been established, last-connected defaults to the
first endpoint listed.";
}
leaf interval-secs {
type uint8;
units seconds;
default 5;
description
"Specifies the time delay between connection attempts
to the same endpoint. Note: this value differs from
the periodic-connection's timeout-mins value.";
}
leaf count-max {
type uint8;
default 3;
description
"Specifies the number times the device tries to
connect to a specific endpoint before moving on to
the next endpoint in the list (round robin).";
}
}
}
}
}
grouping listen-config {
description
"Provides the configuration of the NETCONF server to
open one or more ports to listen for incoming client
connections.";
container ssh {
if-feature ssh-listen;
uses one-or-many-config {
refine one-or-many/one-port/port {
default 830;
}
refine one-or-many/many-ports/interface/port {
default 830;
}
}
}
container tls {
if-feature tls-listen;
uses one-or-many-config {
refine one-or-many/one-port/port {
default 6513;
}
refine one-or-many/many-ports/interface/port {
default 6513;
}
}
}
}
grouping call-home-config {
description
"Provides the configuration of the NETCONF call-home
clients to connect to, the overall call-home policy,
and the reconnect strategy.";
uses network-managers-config {
augment network-managers/network-manager/transport {
container ssh {
if-feature ssh-call-home;
container host-keys {
description
"An ordered listing of the SSH host keys the
device should advertise to the network manager.";
list host-key {
key name;
min-elements 1; // requires 'ssh' element?
ordered-by user;
leaf name {
type string;
mandatory true;
description
"The name of a host key the device should
advertise during the SSH key exchange.";
}
}
}
}
container tls {
if-feature tls-call-home;
presence "Enables call home using TLS when configured.";
}
}
}
}
// Module's top-level container
container netconf-server {
description
"Top-level container for NETCONF server configuration.";
container listen {
uses listen-config;
}
container call-home {
uses call-home-config;
}
}
}
<CODE ENDS>
]]></artwork>
</figure>
</t>
</section>
</section>
<section title="Keep-Alives for SSH and TLS">
<t>One the objectives listed above, <xref target="keepalives">
Keep-Alives for Persistent Connections</xref> indicates a need
for a "keep-alive" mechanism. This section specifies how the
NETCONF keep-alive mechanism is to be implemented.</t>
<t>Both SSH and TLS have the ability to support keep-alives.
Using these mechanisms, the keep-alive messages are sent inside
the encrypted tunnel, thus thwarting spoof attacks.</t>
<section title="SSH">
<t>The SSH keep-alive solution that is expected to be used
when configured using the data model defined in this document
is ubiquitous in practice, though never being explicitly defined
in an RFC. The strategy used is to purposely send a malformed
request message with a flag set to ensure a response. More
specifically, per section 4 of <xref target="RFC4253"/>, either
SSH peer can send a SSH_MSG_GLOBAL_REQUEST message with "want
reply" set to '1' and that, if there is an error, will get back
a SSH_MSG_REQUEST_FAILURE response. Similarly, section 5 of
<xref target="RFC4253"/> says that either SSH peer can send a
SSH_MSG_CHANNEL_REQUEST message with "want reply" set to '1'
and that, if there is an error, will get back a
SSH_MSG_CHANNEL_FAILURE response.</t>
<t>To ensure that the request will fail, current implementations
send an invalid "request name" or "request type", respectively.
Abiding to the extensibility guidelines specified in Section 6
of <xref target="RFC4251"/>, these implementations use the
"name@domain". For instance, when configured to send keep-alives,
OpenSSH sends the string "keepalive@openssh.com". In order to
remain compatible with existing implementations, this draft does
not require a specific "request name" or "request type" string
be used.</t>
</section>
<section title="TLS">
<t>The TLS keep-alive solution is defined in <xref target="RFC6520"/>.
This solution allows both peers to advertise if they can
receive heartbeat request messages from its peer.
For standard NETCONF over TLS connections, devices SHOULD
advertise "peer_allowed_to_send", as per <xref target="RFC6520"/>.
This advertisement is not a "MUST" in order to grandfather
existing NETCONF over TLS implementations.
For NETCONF over TLS Call Home, the network management
system MUST advertise "peer_allowed_to_send" per
<xref target="RFC6520"/>. This is a "MUST" so as to ensure
devices can depend in it always being there for call home
connections, which is conveniently when keep-alives are
needed the most.</t>
</section>
</section>
<section title="User Authentication for TLS">
<section title="Introduction">
<t>The NETCONF Server Module defined in this draft focuses on the
configuration the SSH and TLS transports. This module does not
define a means to configure User Authentication, as that is a
stated focus for <xref target="draft-ietf-netmod-system-mgmt"/>,
however, that draft does not define configuration nodes for
TLS client authentication. Thus, this draft also includes the
following YANG module to augment TLS client authentication into
the "ietf-system" module defined in
<xref target="draft-ietf-netmod-system-mgmt"/>.</t>
</section>
<section title="Data Model Overview">
<t>This data model augments the "ietf-system" module
defined in <xref target="draft-ietf-netmod-system-mgmt"/>
by adding some configuration nodes under its
"/system/authentication" subtree.</t>
<t>
<figure>
<artwork><![CDATA[
module: ietf-system-tls-auth
augment /sys:system/sys:authentication:
+--rw tls
+--rw trusted-ca-certs
| +--rw trusted-ca-cert* binary
+--rw trusted-client-certs
| +--rw trusted-client-cert* binary
+--rw cert-maps {tls-map-certificates}?
| +--rw cert-to-name* [id]
| +--rw id uint32
| +--rw fingerprint x509c2n:tls-fingerprint
| +--rw map-type identityref
| +--rw name string
+--rw psk-maps {tls-map-pre-shared-keys}?
+--rw psk-map* [psk-identity]
+--rw psk-identity string
+--rw user-name nacm:user-name-type
+--rw not-valid-before? yang:date-and-time
+--rw not-valid-after? yang:date-and-time
+--rw key yang:hex-string
]]></artwork>
</figure>
</t>
</section>
<section title="YANG Module">
<t>This YANG module imports YANG extensions from <xref
target="RFC6536"/>, and imports YANG types from <xref
target="RFC6991"/> and a YANG grouping from <xref
target="I-D.ietf-netmod-snmp-cfg"/>.</t>
<t>
<figure>
<!--<preamble>The YANG Module</preamble>-->
<artwork><![CDATA[
RFC Ed.: update the date below with the date of RFC publication
and remove this note.
<CODE BEGINS> file "ietf-system-tls-auth.@2014-05-16.yang"
module ietf-system-tls-auth {
namespace "urn:ietf:params:xml:ns:yang:ietf-system-tls-auth";
prefix "system-tls-auth";
import ietf-system { // draft-ietf-netmod-system-mgmt
prefix "sys";
}
import ietf-netconf-acm {
prefix nacm; // RFC 6536
}
import ietf-yang-types {
prefix yang; // RFC 6991
}
import ietf-x509-cert-to-name {
prefix x509c2n; // I-D.ietf-netconf-rfc5539bis
}
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: Bert Wijnen
<mailto:bertietf@bwijnen.net>
Editor: Kent Watsen
<mailto:kwatsen@juniper.net>
Juergen Schoenwaelder
<mailto:j.schoenwaelder@jacobs-university.de>";
description
"This module augments the ietf-system module in order to
add TLS authentication configuration nodes to the
'authentication' container.
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.";
// RFC Ed.: replace XXXX with actual RFC number and
// remove this note
// RFC Ed.: please update the date to the date of publication
revision "2014-05-24" {
description
"Initial version";
reference
"RFC XXXX: NETCONF Server Configuration Model";
}
// Features
feature tls-map-certificates {
description
"The tls-map-certificates feature indicates that the
NETCONF server implements mapping X.509 certificates to NETCONF
usernames.";
}
feature tls-map-pre-shared-keys {
description
"The tls-map-pre-shared-keys feature indicates that the
NETCONF server implements mapping TLS pre-shared keys to NETCONF
usernames.";
}
grouping tls-global-config {
container trusted-ca-certs {
description
"A list of Certificate Authority (CA) certificates that a
NETCONF server can use to authenticate a NETCONF client's
certificate. A client's certificate is authenticated if
its Issuer matches one of the configured trusted CA
certificates.";
leaf-list trusted-ca-cert {
type binary;
ordered-by system;
description
"The binary certificate structure, as
specified by RFC 5246, Section 7.4.6, i.e.,:
opaque ASN.1Cert<1..2^24>;
";
reference
"RFC 5246: The Transport Layer Security (TLS)
Protocol Version 1.2";
}
}
container trusted-client-certs {
description
"A list of client certificates that a NETCONF server can
use to authenticate a NETCONF client's certificate. A
client's certificate is authenticated if it is an exact
match to one of the configured trusted client certificates.";
leaf-list trusted-client-cert {
type binary;
ordered-by system;
description
"The binary certificate structure, as
specified by RFC 5246, Section 7.4.6, i.e.,:
opaque ASN.1Cert<1..2^24>;
";
reference
"RFC 5246: The Transport Layer Security (TLS)
Protocol Version 1.2";
}
}
// Objects for deriving NETCONF usernames from X.509
// certificates.
container cert-maps {
if-feature tls-map-certificates;
uses x509c2n:cert-to-name;
description
"The cert-maps container is used by a 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.";
}
// Objects for deriving NETCONF usernames from TLS
// pre-shared keys.
container psk-maps {
if-feature tls-map-pre-shared-keys;
description
"During the TLS Handshake, the client indicates which
key to use by including a PSK identity in the TLS
ClientKeyExchange message. On the NETCONF server side,
this PSK identity is used to look up an entry in the psk-map
list. If such an entry is found, and the pre-shared keys
match, then the client is authenticated. The NETCONF
server uses the value from the user-name leaf in the
psk-map list as the NETCONF username. If the NETCONF
server cannot find an entry in the psk-map list, or if
the pre-shared keys do not match, then the NETCONF
server terminates the connection.";
reference
"RFC 4279: Pre-Shared Key Ciphersuites for Transport Layer
Security (TLS)";
list psk-map {
key psk-identity;
leaf psk-identity {
type string;
description
"The PSK identity encoded as a UTF-8 string. For
details how certain common PSK identity formats can
be encoded in UTF-8, see section 5.1. of RFC 4279.";
reference
"RFC 4279: Pre-Shared Key Ciphersuites for Transport
Layer Security (TLS)";
}
leaf user-name {
type nacm:user-name-type;
mandatory true;
description
"The NETCONF username associated with this PSK
identity.";
}
leaf not-valid-before {
type yang:date-and-time;
description
"This PSK identity is not valid before the given date
and time.";
}
leaf not-valid-after {
type yang:date-and-time;
description
"This PSK identity is not valid after the given date
and time.";
}
leaf key {
type yang:hex-string;
mandatory true;
nacm:default-deny-all;
description
"The key associated with the PSK identity";
reference
"RFC 4279: Pre-Shared Key Ciphersuites for Transport
Layer Security (TLS)";
}
}
}
}
augment "/sys:system/sys:authentication" {
container tls {
uses tls-global-config;
}
}
}
<CODE ENDS>
]]></artwork>
</figure>
</t>
</section>
</section>
<section title="Security Considerations">
<t>The YANG modules defined in this memo are designed to be
accessed via the NETCONF protocol <xref target="RFC6241"/>.
Authorization for access to specific portions of conceptual
data and operations within this module is provided by the
NETCONF access control model (NACM) <xref target="RFC6536"/>.</t>
<t>There are a number of data nodes defined in the
"ietf-netconf-server" and "ietf-system-tls-auth" YANG
modules which 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 and read operations to
these data nodes can have a negative effect on network
operations. It is thus important to control write
and read access to these data nodes. Below are the
data nodes and their sensitivity/vulnerability.</t>
<t>ietf-netconf-server:
<list style="symbols">
<t>None.</t>
</list>
</t>
<t>ietf-system-tls-auth:
<list style="symbols">
<t>/system/authentication/tls/psk-maps/psk-map/user-name:
This leaf node contains a user name that some deployments
may consider sensitive information.</t>
<t>/system/authentication/tls/psk-maps/psk-map/key: This
leaf node contains a shared key that remote clients use
to authenticate themselves to the system. This value
should not be readable or writable by anyone by default.</t>
</list>
</t>
</section>
<section title="IANA Considerations">
<t>This document registers two URIs in the IETF XML
registry <xref target="RFC2119"/>. Following the format in
<xref target="RFC3688"/>, the following registrations are
requested:</t>
<t>
<figure>
<artwork><![CDATA[
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.
URI: urn:ietf:params:xml:ns:yang:ietf-system-tle-auth
Registrant Contact: The NETCONF WG of the IETF.
XML: N/A, the requested URI is an XML namespace.
]]></artwork>
</figure>
</t>
<t>This document registers two YANG modules in the
YANG Module Names registry <xref target="RFC6020"/>.</t>
<t>
<figure>
<artwork><![CDATA[
name: ietf-netconf-server
namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-server
prefix: ncserver
reference: RFC XXXX
name: ietf-system-tls-auth
namespace: urn:ietf:params:xml:ns:yang:ietf-system-tls-auth
prefix: sys-tls-auth
reference: RFC XXXX
]]></artwork>
</figure>
</t>
</section>
<section title="Other Considerations">
<t>The YANG module define herein does not itself support
virtual routing and forwarding (VRF). It is expected that
external modules will augment in VRF designations when needed.</t>
</section>
<section title="Acknowledgements">
<t>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, David Lamparter, Alan Luchuk, Ladislav Lhotka,
Radek Krejci, Tom Petch, and Phil Shafer.</t>
<t>
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.
</t>
</section>
</middle>
<back>
<references title="Normative References">
<reference anchor="RFC2119">
<front>
<title>
Key words for use in RFCs to Indicate Requirement Levels
</title>
<author initials="S.B." surname="Bradner"
fullname="Scott Bradner">
<organization>Harvard University</organization>
</author>
<date month="March" year="1997" />
</front>
<seriesInfo name="BCP" value="14" />
<seriesInfo name="RFC" value="2119" />
</reference>
<reference anchor="RFC4251">
<front>
<title>
The Secure Shell (SSH) Protocol Architecture
</title>
<author initials="T.Y." surname="Ylonen"
fullname="Tatu Ylonen">
<organization>
SSH Communications Security Corp
</organization>
</author>
<author initials="C.L." surname="Lonvick"
fullname="Chris Lonvick">
<organization>
Cisco Systems, Inc.
</organization>
</author>
<date month="January" year="2006" />
</front>
<seriesInfo name="RFC" value="4251" />
</reference>
<reference anchor="RFC4253">
<front>
<title>
The Secure Shell (SSH) Transport Layer Protocol
</title>
<author initials="T.Y." surname="Ylonen"
fullname="Tatu Ylonen">
<organization>
SSH Communications Security Corp
</organization>
</author>
<author initials="C.L." surname="Lonvick"
fullname="Chris Lonvick">
<organization>
Cisco Systems, Inc.
</organization>
</author>
<date month="January" year="2006" />
</front>
<seriesInfo name="RFC" value="4253" />
</reference>
<reference anchor="RFC6020">
<front>
<title>
YANG - A Data Modeling Language for the
Network Configuration Protocol (NETCONF)
</title>
<author initials="M." surname="Bjorklund"
fullname="Martin Bjorklund" role="editor">
<organization>Tail-f Systems</organization>
</author>
<date month="October" year="2010" />
</front>
<seriesInfo name="RFC" value="6020" />
</reference>
<reference anchor='RFC6520'>
<front>
<title>
Transport Layer Security (TLS) and Datagram Transport
Layer Security (DTLS) Heartbeat Extension
</title>
<author initials='R.S.' surname='Seggelmann'
fullname='Robin Seggleman'>
<organization>Muenster University of Applied Sciences</organization>
</author>
<author initials='M.T.' surname='Tuexen'
fullname='Michael Tuexen'>
<organization>Muenster University of Applied Sciences</organization>
</author>
<author initials='M.W.' surname='Williams'
fullname='Michael Williams'>
<organization>GWhiz Arts & Sciences</organization>
</author>
<date year='2012' month='February' />
</front>
<seriesInfo name='RFC' value='6520' />
</reference>
<reference anchor='RFC6536'>
<front>
<title>
Network Configuration Protocol (NETCONF) Access
Control Model
</title>
<author initials='A.' surname='Bierman'
fullname='A. Bierman'>
<organization>YumaWorks</organization>
</author>
<author initials='M.' surname='Bjorklund'
fullname='M. Bjorklund'>
<organization>Tail-f Systems</organization>
</author>
<date year='2012' month='March' />
</front>
<seriesInfo name='RFC' value='6536' />
</reference>
<reference anchor='RFC6991'>
<front>
<title>Common YANG Data Types</title>
<author initials='J.' surname='Schoenwaelder'
fullname='J. Schoenwaelder'>
<organization>Jacobs University</organization>
</author>
<date year='2013' month='July' />
</front>
<seriesInfo name='RFC' value='6991' />
</reference>
<reference anchor="RFC6241">
<front>
<title>NETCONF Configuration Protocol</title>
<author initials="R.E." surname="Enns"
fullname="Rob Enns" role="editor">
<organization>Juniper Networks</organization>
</author>
<author initials="M.B." surname="Bjorklund"
fullname="Martin Bjorklund" role="editor">
<organization>Tail-f Systems</organization>
</author>
<author initials="J.S." surname="Schoenwaelder"
fullname="Juergen Schoenwaelder" role="editor">
<organization>Jacobs University</organization>
</author>
<author initials="A.B." surname="Bierman"
fullname="Andy Bierman" role="editor">
<organization>Brocade</organization>
</author>
<date month="June" year="2011" />
</front>
<seriesInfo name="RFC" value="6241" />
</reference>
<reference anchor="RFC6242">
<front>
<title>Using the NETCONF Protocol over Secure Shell (SSH)</title>
<author initials="M.W." surname="Wasserman"
fullname="Margaret Wasserman">
<organization>Painless Security, LLC</organization>
</author>
<date month="June" year="2011" />
</front>
<seriesInfo name="RFC" value="6242"/>
</reference>
<reference anchor='I-D.ietf-netconf-rfc5539bis'>
<front>
<title>
Using the NETCONF Protocol over Transport Layer
Security (TLS)
</title>
<author initials='M' surname='Badra'
fullname='Mohamad Badra'>
<organization>LIMOS Laboratory</organization>
</author>
<author initials='A' surname='Luchuk'
fullname='Alan Luchuk'>
<organization>SNMP Research, Inc.</organization>
</author>
<author initials='J' surname='Schönwälder'
fullname='Jürgen Schönwälder'>
<organization>Jacobs University</organization>
</author>
<date month='October' day='21' year='2013' />
</front>
<seriesInfo name='Internet-Draft'
value='draft-ietf-netconf-rfc5539bis-04' />
</reference>
<reference anchor='I-D.ietf-netmod-snmp-cfg'>
<front>
<title>A YANG Data Model for SNMP Configuration</title>
<author initials='M' surname='Bjorklund'
fullname='Martin Bjorklund'>
<organization>Tail-f Systems</organization>
</author>
<author initials='J' surname='Schönwälder'
fullname='Jürgen Schönwälder'>
<organization>Jacobs University</organization>
</author>
<date month='November' day='5' year='2013' />
</front>
<seriesInfo name='Internet-Draft' value='draft-ietf-netmod-snmp-cfg-03' />
</reference>
<reference anchor='draft-ieft-netconf-reverse-ssh'>
<front>
<title>
NETCONF over SSH Call Home
</title>
<author initials='K.W.' surname='Watsen'
fullname='Kent Watsen'>
<organization>Juniper Networks</organization>
</author>
<date month='May' day='17' year='2014' />
</front>
<seriesInfo name='Internet-Draft'
value='draft-ieft-netconf-reverse-ssh-00' />
</reference>
<reference anchor='draft-ietf-netmod-system-mgmt'>
<front>
<title>
A YANG Data Model for System Management
</title>
<author initials='A.B.' surname='Bierman'
fullname='Andy Bierman'>
<organization>YumaWorks</organization>
</author>
<date month='May' day='14' year='2014' />
</front>
<seriesInfo name='Internet-Draft'
value='draft-ieft-netmod-system-mgmt-16' />
</reference>
</references>
<references title="Informative References">
<reference anchor="RFC3688">
<front>
<title>The IETF XML Registry</title>
<author initials="M.M." surname="Mealling"
fullname="Michael Mealling">
<organization>VeriSign Inc.</organization>
</author>
<date month="January" year="2004" />
</front>
<seriesInfo name="BCP" value="81" />
<seriesInfo name="RFC" value="3688"/>
</reference>
</references>
<section title="Example: SSH Transport Configuration">
<t>
<figure>
<artwork><![CDATA[
<netconf-server xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-server">
<listen>
<ssh>
<port>831</port>
</ssh>
</listen>
<call-home>
<network-managers>
<network-manager>
<name>config-mgr</name>
<description>
This entry requests the device to periodically
connect to the network manager.
</description>
<endpoints>
<endpoint>
<address>config-mgr1.example.com</address>
</endpoint>
<endpoint>
<address>config-mgr2.example.com</address>
</endpoint>
</endpoints>
<transport>
<ssh>
<host-keys>
<host-key>
<name>ssh_host_key_cert</name>
</host-key>
<host-key>
<name>ssh_host_key_cert2</name>
</host-key>
</host-keys>
</ssh>
</transport>
<connection-type>
<periodic>
<timeout-mins>5</timeout-mins>
<linger-secs>10</linger-secs>
</periodic>
</connection-type>
<reconnect-strategy>
<start-with>last-connected</start-with>
<interval-secs>10</interval-secs>
<count-max>3</count-max>
</reconnect-strategy>
</network-manager>
</network-managers>
</call-home>
</netconf-server>
]]></artwork>
</figure>
</t>
</section>
<section title="Example: TLS Transport Configuration">
<t>
<figure>
<artwork><![CDATA[
<netconf-server xmlns="urn:ietf:params:xml:ns:yang:ietf-netconf-server">
<listen>
<tls>
<interface>
<address>192.0.2.1</address>
<port>6514</port>
</interface>
</tls>
</listen>
<call-home>
<network-managers>
<network-manager>
<name>log-monitor</name>
<description>
This entry requests the device to maintain a
persistent connect to the network manager.
</description>
<endpoints>
<endpoint>
<address>log-monitor1.example.com</address>
</endpoint>
<endpoint>
<address>log-monitor2.example.com</address>
</endpoint>
</endpoints>
<transport>
<tls/>
</transport>
<connection-type>
<persistent>
<keep-alives>
<interval-secs>5</interval-secs>
<count-max>3</count-max>
</keep-alives>
</persistent>
</connection-type>
<reconnect-strategy>
<start-with>first-listed</start-with>
<interval-secs>10</interval-secs>
<count-max>4</count-max>
</reconnect-strategy>
</network-manager>
</network-managers>
</call-home>
</netconf-server>
]]></artwork>
</figure>
</t>
</section>
<section title="Example: TLS Authentication Configuration">
<t>
<figure>
<artwork><![CDATA[
<system xmlns="urn:ietf:params:xml:ns:yang:ietf-system">
<authentication>
<tls xmlns="urn:ietf:params:xml:ns:yang:ietf-system-tls-auth">
<trusted-ca-certs>
<trusted-ca-cert>
QW4gRWFzdGVyIGVnZywgZm9yIHRob3NlIHdobyBtaWdodCBsb29rICA6KQo=
</trusted-ca-cert>
</trusted-ca-certs>
<trusted-client-certs>
<trusted-client-cert>
SSBhbSB0aGUgZWdnIG1hbiwgdGhleSBhcmUgdGhlIGVnZyBtZW4uCg==
</trusted-client-cert>
<trusted-client-cert>
SSBhbSB0aGUgd2FscnVzLCBnb28gZ29vIGcnam9vYi4K
</trusted-client-cert>
</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>11:0A:05:11:00</fingerprint>
<map-type>x509c2n:specified</map-type>
<name>Joe Cool</name>
</cert-to-name>
</cert-maps>
<psk-maps>
<psk-map>
<psk-identity>a8gc8]klh59</psk-identity>
<user-name>admin</user-name>
<not-valid-before>2013-01-01T00:00:00Z</not-valid-before>
<not-valid-after>2014-01-01T00:00:00Z</not-valid-after>
</psk-map>
</psk-maps>
</tls>
</authentication>
</system>
]]></artwork>
</figure>
</t>
</section>
<section title="Change Log">
<section title="I-D to 00">
<t>
<list style="symbols">
<t>Changed title to "NETCONF Server Configuration Model"</t>
<t>Mapped inbound/outbound to listen/call-home</t>
<t>Restructured YANG module to place transport
selection deeper into the tree, providing a more
intuitive data model</t>
<t>Added section "Keep-Alives for SSH and TLS"</t>
<t>Updated the Security Considerations section</t>
<t>Added text for supporting VRFs via augments</t>
<t>Factored the TLS-AUTH config into another module
augmenting the "ietf-system" module</t>
</list>
</t>
</section>
<section title="00 to 01">
<t>
<list style="symbols">
<t>Restructured document so it flows better</t>
<t>Added trusted-ca-certs and trusted-client-certs
objects into the ietf-system-tls-auth module</t>
</list>
</t>
</section>
</section>
<section title="Open Issues">
<t>
<list style="symbols">
<t>NETCONF implementations typically have config
parameters such as session timeouts or hello
timeouts. Shall they be included in this model?</t>
<t>Do we need knobs to enable/disable call-home without
the need to remove all the call-home client
configuration?</t>
</list>
</t>
</section>
</back>
</rfc>
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