RESTCONF Client and Server ModelsWatsen Networkskent+ietf@watsen.net
Operations
NETCONF Working GroupThis document defines two YANG modules,
one module to configure a RESTCONF client and the other module to
configure a RESTCONF server. Both modules support the TLS transport
protocol with both standard RESTCONF and RESTCONF Call Home connections.Editorial Note (To be removed by RFC Editor)This draft contains 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 shorthand references to drafts in
progress. Please apply the following replacements (note: not all may be present):
AAAA --> the assigned RFC value for draft-ietf-netconf-crypto-types
BBBB --> the assigned RFC value for draft-ietf-netconf-trust-anchors
CCCC --> the assigned RFC value for draft-ietf-netconf-keystore
DDDD --> the assigned RFC value for draft-ietf-netconf-tcp-client-server
EEEE --> the assigned RFC value for draft-ietf-netconf-ssh-client-server
FFFF --> the assigned RFC value for draft-ietf-netconf-tls-client-server
GGGG --> the assigned RFC value for draft-ietf-netconf-http-client-server
HHHH --> the assigned RFC value for draft-ietf-netconf-netconf-client-server
IIII --> the assigned RFC value for this draft
Artwork in this document contains placeholder values for the date of publication of this
draft. Please apply the following replacement:
2022-03-07 --> the publication date of this draft
The following Appendix section is to be removed prior to publication:
. Change Log
IntroductionThis document defines two YANG modules,
one module to configure a RESTCONF client and the other module to
configure a RESTCONF server .
Both modules support the TLS transport
protocol with both standard RESTCONF and RESTCONF Call Home connections
.Relation to other RFCsThis document presents one or more YANG modules
that are part of a collection of RFCs that work together to,
ultimately, enable the configuration of the clients and
servers of both the NETCONF and RESTCONF
protocols.The modules have been defined in a modular fashion to enable
their use by other efforts, some of which are known to be in
progress at the time of this writing, with many more expected
to be defined in time.The normative dependency relationship between the various RFCs in the collection
is presented in the below diagram. The labels in the diagram
represent the primary purpose provided by each RFC. Hyperlinks to
each RFC are provided below the diagram.
Label to RFC Mapping
Label in Diagram
Originating RFC
crypto-types
truststore
keystore
tcp-client-server
ssh-client-server
tls-client-server
http-client-server
netconf-client-server
restconf-client-server
Specification LanguageThe 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
when, and only when, they appear in all capitals, as shown here.Adherence to the NMDAThis document is compliant with the Network Management Datastore
Architecture (NMDA) . For instance, as
described in and
, trust anchors and keys
installed during manufacturing are expected to appear
in <operational>.ConventionsVarious examples used in this document use a placeholder
value for binary data that has been base64 encoded (e.g.,
"BASE64VALUE="). This placeholder value is used as real
base64 encoded structures are often many lines long and
hence distracting to the example being presented.The "ietf-restconf-client" ModuleThe RESTCONF client model presented in this section supports
both clients initiating connections to servers, as well as
clients listening for connections from servers calling home.YANG feature statements are used to enable implementations to
advertise which potentially uncommon parts of the model the
RESTCONF client supports.Data Model OverviewThis section provides an overview of the "ietf-restconf-client"
module in terms of its features and groupings.FeaturesThe following diagram lists all the "feature" statements
defined in the "ietf-restconf-client" module:GroupingsThe "ietf-restconf-client" module defines the following "grouping" statements:
restconf-client-grouping
restconf-client-initiate-stack-grouping
restconf-client-listen-stack-grouping
restconf-client-app-grouping
Each of these groupings are presented in the following subsections.The "restconf-client-grouping" GroupingThe following tree diagram illustrates the
"restconf-client-grouping" grouping:
]]>Comments:
This grouping does not define any nodes, but is maintained so
that downstream modules can augment nodes into it if needed.
The "restconf-client-grouping" defines, if it can be called
that, the configuration for just "RESTCONF" part of a protocol
stack. It does not, for instance, define any configuration for
the "TCP", "TLS", or "HTTP" protocol layers (for that, see
and ).
The "restconf-client-initiate-stack-grouping" GroupingThe following tree diagram illustrates the
"restconf-client-initiate-stack-grouping" grouping:Comments:
The "restconf-client-initiate-stack-grouping" defines the
configuration for a full RESTCONF protocol stack, for RESTCONF
clients that initiate connections to RESTCONF servers, as
opposed to receiving call-home
connections.
The "transport" choice node enables transport options to be
configured. This document only defines an "https" option,
but other options MAY be augmented in.
For the referenced grouping statement(s):
The "tcp-client-grouping" grouping is discussed in
.
The "tls-client-grouping" grouping is discussed in
.
The "http-client-grouping" grouping is discussed in
.
The "restconf-client-grouping" grouping is discussed in
in this document.
The "restconf-client-listen-stack-grouping" GroupingThe following tree diagram illustrates the
"restconf-client-listen-stack-grouping" grouping:Comments:
The "restconf-client-listen-stack-grouping" defines the
configuration for a full RESTCONF protocol stack, for RESTCONF
clients that receive call-home
connections from RESTCONF servers.
The "transport" choice node enables both the HTTP and
HTTPS transports to be configured, with each option
enabled by a "feature" statement. Note that RESTCONF
requires HTTPS, the HTTP option is provided to support
cases where a TLS-terminator is deployed in front of
the RESTCONF-client.
For the referenced grouping statement(s):
The "tcp-server-grouping" grouping is discussed in
.
The "tls-client-grouping" grouping is discussed in
.
The "http-client-grouping" grouping is discussed in
.
The "restconf-client-grouping" grouping is discussed in
in this document.
The "restconf-client-app-grouping" GroupingThe following tree diagram illustrates the
"restconf-client-app-grouping" grouping:Comments:
The "restconf-client-app-grouping" defines the configuration
for a RESTCONF client that supports both initiating connections
to RESTCONF servers as well as receiving call-home connections from
RESTCONF servers.
Both the "initiate" and "listen" subtrees must be enabled by
"feature" statements.
For the referenced grouping statement(s):
The "restconf-client-initiate-stack-grouping" grouping is discussed in
in this document.
The "restconf-client-listen-stack-grouping" grouping is discussed in
in this document.
Protocol-accessible NodesThe following tree diagram lists all the protocol-accessible nodes
defined in the "ietf-restconf-client" module:Comments:
Protocol-accessible nodes are those nodes that are accessible
when the module is "implemented", as described in .
For the "ietf-restconf-client" module, the protocol-accessible nodes
are an instance of the "restconf-client-app-grouping" discussed in
grouping.
The reason for why "restconf-client-app-grouping" exists separate from
the protocol-accessible nodes definition is so as to enable
instances of restconf-client-app-grouping to be instantiated in other
locations, as may be needed or desired by some modules.
Example UsageThe following example illustrates configuring a RESTCONF
client to initiate connections, as well as to listen for call-home
connections.This example is consistent with the examples presented in
and
.corp-fw1corp-fw1.example.comcorp-fw1.example.com15330rsa-asymmetric-key
ex-rsa-certtrusted-server-ca-certs
trusted-server-ee-certs
303bobsecretcorp-fw2.example.comcorp-fw2.example.com15330rsa-asymmetric-key
ex-rsa-certtrusted-server-ca-certs
trusted-server-ee-certs
303bobsecretIntranet-facing listener11.22.33.44rsa-asymmetric-keyex-rsa-certtrusted-server-ca-certs
trusted-server-ee-certs
bobsecret
]]>YANG ModuleThis YANG module has normative references to ,
, and ,
,
, and
.<CODE BEGINS> file "ietf-restconf-client@2022-03-07.yang"
Author: Kent Watsen
Author: Gary Wu ";
description
"This module contains a collection of YANG definitions
for configuring RESTCONF clients.
Copyright (c) 2021 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 Revised
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 IIII
(https://www.rfc-editor.org/info/rfcIIII); 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 2022-03-07 {
description
"Initial version";
reference
"RFC IIII: RESTCONF Client and Server Models";
}
// Features
feature https-initiate {
description
"The 'https-initiate' feature indicates that the RESTCONF
client supports initiating HTTPS connections to RESTCONF
servers. This feature exists as HTTPS might not be a
mandatory to implement transport in the future.";
reference
"RFC 8040: RESTCONF Protocol";
}
feature http-listen {
description
"The 'https-listen' feature indicates that the RESTCONF client
supports opening a port to listen for incoming RESTCONF
server call-home connections. This feature exists as not
all RESTCONF clients may support RESTCONF call home.";
reference
"RFC 8071: NETCONF Call Home and RESTCONF Call Home";
}
feature https-listen {
description
"The 'https-listen' feature indicates that the RESTCONF client
supports opening a port to listen for incoming RESTCONF
server call-home connections. This feature exists as not
all RESTCONF clients may support RESTCONF call home.";
reference
"RFC 8071: NETCONF Call Home and RESTCONF Call Home";
}
// Groupings
grouping restconf-client-grouping {
description
"A reusable grouping for configuring a RESTCONF client
without any consideration for how underlying transport
sessions are established.
This grouping currently does not define any nodes.";
}
grouping restconf-client-initiate-stack-grouping {
description
"A reusable grouping for configuring a RESTCONF client
'initiate' protocol stack for a single connection.";
choice transport {
mandatory true;
description
"Selects between available transports. This is a
'choice' statement so as to support additional
transport options to be augmented in.";
case https {
if-feature "https-initiate";
container https {
must 'tls-client-parameters/client-identity
or http-client-parameters/client-identity';
description
"Specifies HTTPS-specific transport
configuration.";
container tcp-client-parameters {
description
"A wrapper around the TCP client parameters
to avoid name collisions.";
uses tcpc:tcp-client-grouping {
refine "remote-port" {
default "443";
description
"The RESTCONF client will attempt to
connect to the IANA-assigned well-known
port value for 'https' (443) if no value
is specified.";
}
}
}
container tls-client-parameters {
description
"A wrapper around the TLS client parameters
to avoid name collisions.";
uses tlsc:tls-client-grouping;
}
container http-client-parameters {
description
"A wrapper around the HTTP client parameters
to avoid name collisions.";
uses httpc:http-client-grouping;
}
container restconf-client-parameters {
description
"A wrapper around the HTTP client parameters
to avoid name collisions.";
uses rcc:restconf-client-grouping;
}
}
}
}
} // restconf-client-initiate-stack-grouping
grouping restconf-client-listen-stack-grouping {
description
"A reusable grouping for configuring a RESTCONF client
'listen' protocol stack for a single connection. The
'listen' stack supports call home connections, as
described in RFC 8071";
reference
"RFC 8071: NETCONF Call Home and RESTCONF Call Home";
choice transport {
mandatory true;
description
"Selects between available transports. This is a
'choice' statement so as to support additional
transport options to be augmented in.";
case http {
if-feature "http-listen";
container http {
description
"HTTP-specific listening configuration for inbound
connections.
This transport option is made available to support
deployments where the TLS connections are terminated
by another system (e.g., a load balanacer) fronting
the client.";
container tcp-server-parameters {
description
"A wrapper around the TCP client parameters
to avoid name collisions.";
uses tcps:tcp-server-grouping {
refine "local-port" {
default "4336";
description
"The RESTCONF client will listen on the IANA-
assigned well-known port for 'restconf-ch-tls'
(4336) if no value is specified.";
}
}
}
container http-client-parameters {
description
"A wrapper around the HTTP client parameters
to avoid name collisions.";
uses httpc:http-client-grouping;
}
container restconf-client-parameters {
description
"A wrapper around the RESTCONF client parameters
to avoid name collisions.";
uses rcc:restconf-client-grouping;
}
}
}
case https {
if-feature "https-listen";
container https {
must 'tls-client-parameters/client-identity
or http-client-parameters/client-identity';
description
"HTTPS-specific listening configuration for inbound
connections.";
container tcp-server-parameters {
description
"A wrapper around the TCP client parameters
to avoid name collisions.";
uses tcps:tcp-server-grouping {
refine "local-port" {
default "4336";
description
"The RESTCONF client will listen on the IANA-
assigned well-known port for 'restconf-ch-tls'
(4336) if no value is specified.";
}
}
}
container tls-client-parameters {
description
"A wrapper around the TLS client parameters
to avoid name collisions.";
uses tlsc:tls-client-grouping;
}
container http-client-parameters {
description
"A wrapper around the HTTP client parameters
to avoid name collisions.";
uses httpc:http-client-grouping;
}
container restconf-client-parameters {
description
"A wrapper around the RESTCONF client parameters
to avoid name collisions.";
uses rcc:restconf-client-grouping;
}
}
}
}
} // restconf-client-listen-stack-grouping
grouping restconf-client-app-grouping {
description
"A reusable grouping for configuring a RESTCONF client
application that supports both 'initiate' and 'listen'
protocol stacks for a multiplicity of connections.";
container initiate {
if-feature "https-initiate";
presence
"Indicates that client-initiated connections have been
configured. This statement is present so the mandatory
descendant nodes do not imply that this node must be
configured.";
description
"Configures client initiating underlying TCP connections.";
list restconf-server {
key "name";
min-elements 1;
description
"List of RESTCONF servers the RESTCONF client is to
maintain simultaneous connections with.";
leaf name {
type string;
description
"An arbitrary name for the RESTCONF server.";
}
container endpoints {
description
"Container for the list of endpoints.";
list endpoint {
key "name";
min-elements 1;
ordered-by user;
description
"A non-empty user-ordered list of endpoints for this
RESTCONF client to try to connect to in sequence.
Defining more than one enables high-availability.";
leaf name {
type string;
description
"An arbitrary name for this endpoint.";
}
uses restconf-client-initiate-stack-grouping;
}
}
container connection-type {
description
"Indicates the RESTCONF client's preference for how
the RESTCONF connection is maintained.";
choice connection-type {
mandatory true;
description
"Selects between available connection types.";
case persistent-connection {
container persistent {
presence
"Indicates that a persistent connection is to be
maintained.";
description
"Maintain a persistent connection to the
RESTCONF server. If the connection goes down,
immediately start trying to reconnect to the
RESTCONF server, using the reconnection strategy.
This connection type minimizes any RESTCONF server
to RESTCONF client data-transfer delay, albeit
at the expense of holding resources longer.";
}
}
case periodic-connection {
container periodic {
presence
"Indicates that a periodic connection is to be
maintained.";
description
"Periodically connect to the RESTCONF server.
This connection type increases resource
utilization, albeit with increased delay
in RESTCONF server to RESTCONF client
interactions.
The RESTCONF client SHOULD gracefully close
the underlying TLS connection upon completing
planned activities.
In the case that the previous connection is
still active, establishing a new connection
is NOT RECOMMENDED.";
leaf period {
type uint16;
units "minutes";
default "60";
description
"Duration of time between periodic
connections.";
}
leaf anchor-time {
type yang:date-and-time {
// constrained to minute-level granularity
pattern '\d{4}-\d{2}-\d{2}T\d{2}:\d{2}'
+ '(Z|[\+\-]\d{2}:\d{2})';
}
description
"Designates a timestamp before or after which
a series of periodic connections are
determined. The periodic connections occur
at a whole multiple interval from the anchor
time. For example, for an anchor time is 15
minutes past midnight and a period interval
of 24 hours, then a periodic connection will
occur 15 minutes past midnight everyday.";
}
leaf idle-timeout {
type uint16;
units "seconds";
default "120"; // two minutes
description
"Specifies the maximum number of seconds
that the underlying TCP session may remain
idle. A TCP session will be dropped if it
is idle for an interval longer than this
number of seconds If set to zero, then the
RESTCONF client will never drop a session
because it is idle.";
}
}
} // periodic-connection
} // connection-type
} // connection-type
container reconnect-strategy {
description
"The reconnection strategy directs how a RESTCONF
client reconnects to a RESTCONF server, after
discovering its connection to the server has
dropped, even if due to a reboot. The RESTCONF
client starts with the specified endpoint and
tries to connect to it max-attempts times before
trying the next endpoint in the list (round
robin).";
leaf start-with {
type enumeration {
enum first-listed {
description
"Indicates that reconnections should start
with the first endpoint listed.";
}
enum last-connected {
description
"Indicates that reconnections should start
with the endpoint last connected to. If
no previous connection has ever been
established, then the first endpoint
configured is used. RESTCONF clients
SHOULD be able to remember the last
endpoint connected to across reboots.";
}
enum random-selection {
description
"Indicates that reconnections should start with
a random endpoint.";
}
}
default "first-listed";
description
"Specifies which of the RESTCONF server's
endpoints the RESTCONF client should start
with when trying to connect to the RESTCONF
server.";
}
leaf max-attempts {
type uint8 {
range "1..max";
}
default "3";
description
"Specifies the number times the RESTCONF client
tries to connect to a specific endpoint before
moving on to the next endpoint in the list
(round robin).";
}
}
}
} // initiate
container listen {
if-feature "http-listen or https-listen";
presence
"Indicates that client-listening ports have been configured.
This statement is present so the mandatory descendant nodes
do not imply that this node must be configured.";
description
"Configures the client to accept call-home TCP connections.";
leaf idle-timeout {
type uint16;
units "seconds";
default "3600"; // one hour
description
"Specifies the maximum number of seconds that an
underlying TCP session may remain idle. A TCP session
will be dropped if it is idle for an interval longer
then 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";
min-elements 1;
description
"List of endpoints to listen for RESTCONF connections.";
leaf name {
type string;
description
"An arbitrary name for the RESTCONF listen endpoint.";
}
uses restconf-client-listen-stack-grouping;
}
}
} // restconf-client-app-grouping
// Protocol accessible node for servers that implement this module.
container restconf-client {
uses restconf-client-app-grouping;
description
"Top-level container for RESTCONF client configuration.";
}
}
]]><CODE ENDS>The "ietf-restconf-server" ModuleThe RESTCONF server model presented in this section supports
both listening for connections as well as initiating call-home
connections.YANG feature statements are used to enable implementations to
advertise which potentially uncommon parts of the model the
RESTCONF server supports.Data Model OverviewThis section provides an overview of the "ietf-restconf-server"
module in terms of its features and groupings.FeaturesThe following diagram lists all the "feature" statements
defined in the "ietf-restconf-server" module:GroupingsThe "ietf-restconf-server" module defines the following "grouping" statements:
restconf-server-grouping
restconf-server-listen-stack-grouping
restconf-server-callhome-stack-grouping
restconf-server-app-grouping
Each of these groupings are presented in the following subsections.The "restconf-server-grouping" GroupingThe following tree diagram illustrates the
"restconf-server-grouping" grouping:Comments:
The "restconf-server-grouping" defines the configuration for just
"RESTCONF" part of a protocol stack. It does not, for instance,
define any configuration for the "TCP", "TLS", or "HTTP" protocol layers
(for that, see
and ).
The "client-identity-mappings" node, which must be enabled by
"feature" statements, defines a mapping from certificate fields
to RESTCONF user names.
For the referenced grouping statement(s):
The "cert-to-name" grouping is discussed in
.
The "restconf-server-listen-stack-grouping" GroupingThe following tree diagram illustrates the
"restconf-server-listen-stack-grouping" grouping:Comments:
The "restconf-server-listen-stack-grouping" defines the
configuration for a full RESTCONF protocol stack for RESTCONF
servers that listen for standard connections from RESTCONF clients,
as opposed to initiating call-home connections.
The "transport" choice node enables both the HTTP and HTTPS
transports to be configured, with each option enabled by a
"feature" statement. The HTTP option is provided to support
cases where a TLS-terminator is deployed in front of
the RESTCONF-server.
For the referenced grouping statement(s):
The "tcp-server-grouping" grouping is discussed in
.
The "tls-server-grouping" grouping is discussed in
.
The "http-server-grouping" grouping is discussed in
.
The "restconf-server-grouping" is discussed in
of this document.
The "restconf-server-callhome-stack-grouping" GroupingThe following tree diagram illustrates the
"restconf-server-callhome-stack-grouping" grouping:Comments:
The "restconf-server-callhome-stack-grouping" defines the
configuration for a full RESTCONF protocol stack, for RESTCONF
servers that initiate call-home connections
to RESTCONF clients.
The "transport" choice node enables transport options to be
configured. This document only defines an "https" option, but
other options MAY be augmented in.
For the referenced grouping statement(s):
The "tcp-client-grouping" grouping is discussed in
.
The "tls-server-grouping" grouping is discussed in
.
The "http-server-grouping" grouping is discussed in
.
The "restconf-server-grouping" is discussed in
of this document.
The "restconf-server-app-grouping" GroupingThe following tree diagram illustrates the
"restconf-server-app-grouping" grouping:Comments:
The "restconf-server-app-grouping" defines the configuration
for a RESTCONF server that supports both listening for connections
from RESTCONF clients as well as initiating call-home connections to
RESTCONF clients.
Both the "listen" and "call-home" subtrees must be enabled by
"feature" statements.
For the referenced grouping statement(s):
The "restconf-server-listen-stack-grouping" grouping is discussed in
in this document.
The "restconf-server-callhome-stack-grouping" grouping is discussed in
in this document.
Protocol-accessible NodesThe following tree diagram lists all the protocol-accessible nodes
defined in the "ietf-restconf-server" module:Comments:
Protocol-accessible nodes are those nodes that are accessible
when the module is "implemented", as described in .
For the "ietf-restconf-server" module, the protocol-accessible nodes
are an instance of the "restconf-server-app-grouping" discussed in
grouping.
The reason for why "restconf-server-app-grouping" exists separate from
the protocol-accessible nodes definition is so as to enable
instances of restconf-server-app-grouping to be instantiated in other
locations, as may be needed or desired by some modules.
Example UsageThe following example illustrates configuring a RESTCONF server
to listen for RESTCONF client connections, as well as configuring
call-home to one RESTCONF client.This example is consistent with the examples presented in
and
.restconf/https11.22.33.44rsa-asymmetric-keyex-rsa-certtrusted-client-ca-certs
trusted-client-ee-certs
foo.example.com111:0A:05:11:00x509c2n:specifiedscooby-doo2x509c2n:san-anyconfig-managereast-data-centereast.example.com15330rsa-asymmetric-key
ex-rsa-certtrusted-client-ca-certs
trusted-client-ee-certs
303foo.example.com111:0A:05:11:00x509c2n:specifiedscooby-doo2x509c2n:san-anywest-data-centerwest.example.com15330rsa-asymmetric-key
ex-rsa-certtrusted-client-ca-certs
trusted-client-ee-certs
303foo.example.com111:0A:05:11:00x509c2n:specifiedscooby-doo2x509c2n:san-any30060last-connected3
]]>YANG ModuleThis YANG module has normative references to ,
, , ,
,
, and
.<CODE BEGINS> file "ietf-restconf-server@2022-03-07.yang"
Author: Kent Watsen
Author: Gary Wu
Author: Juergen Schoenwaelder
";
description
"This module contains a collection of YANG definitions
for configuring RESTCONF servers.
Copyright (c) 2021 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 Revised
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 IIII
(https://www.rfc-editor.org/info/rfcIIII); 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 2022-03-07 {
description
"Initial version";
reference
"RFC IIII: RESTCONF Client and Server Models";
}
// Features
feature http-listen {
description
"The 'http-listen' feature indicates that the RESTCONF server
supports opening a port to listen for incoming RESTCONF over
TPC client connections, whereby the TLS connections are
terminated by an external system.";
reference
"RFC 8040: RESTCONF Protocol";
}
feature https-listen {
description
"The 'https-listen' feature indicates that the RESTCONF server
supports opening a port to listen for incoming RESTCONF over
TLS client connections, whereby the TLS connections are
terminated by the server itself.";
reference
"RFC 8040: RESTCONF Protocol";
}
feature https-call-home {
description
"The 'https-call-home' feature indicates that the RESTCONF
server supports initiating connections to RESTCONF clients.";
reference
"RFC 8071: NETCONF Call Home and RESTCONF Call Home";
}
// Groupings
grouping restconf-server-grouping {
description
"A reusable grouping for configuring a RESTCONF server
without any consideration for how underlying transport
sessions are established.
Note that this grouping uses a fairly typical descendant
node name such that a stack of 'uses' statements will
have name conflicts. It is intended that the consuming
data model will resolve the issue by wrapping the 'uses'
statement in a container called, e.g.,
'restconf-server-parameters'. This model purposely does
not do this itself so as to provide maximum flexibility
to consuming models.";
container client-identity-mappings {
description
"Specifies mappings through which RESTCONF client X.509
certificates are used to determine a RESTCONF username.
If no matching and valid cert-to-name list entry can be
found, then the RESTCONF server MUST close the connection,
and MUST NOT accept RESTCONF messages over it.";
reference
"RFC 7407: A YANG Data Model for SNMP Configuration.";
uses x509c2n:cert-to-name {
refine "cert-to-name/fingerprint" {
mandatory false;
description
"A 'fingerprint' value does not need to be specified
when the 'cert-to-name' mapping is independent of
fingerprint matching. A 'cert-to-name' having no
fingerprint value will match any client certificate
and therefore should only be present at the end of
the user-ordered 'cert-to-name' list.";
}
}
}
}
grouping restconf-server-listen-stack-grouping {
description
"A reusable grouping for configuring a RESTCONF server
'listen' protocol stack for a single connection.";
choice transport {
mandatory true;
description
"Selects between available transports. This is a
'choice' statement so as to support additional
transport options to be augmented in.";
case http {
if-feature "http-listen";
container http {
description
"Configures RESTCONF server stack assuming that
TLS-termination is handled externally.";
container external-endpoint {
presence
"Identifies that an external endpoint has been
configured. This statement is present so the
mandatory descendant nodes do not imply that
this node must be configured.";
description
"Identifies contact information for the external
system that terminates connections before passing
them thru to this server (e.g., a network address
translator or a load balancer). These values have
no effect on the local operation of this server,
but may be used by the application when needing to
inform other systems how to contact this server.";
leaf address {
type inet:ip-address;
mandatory true;
description
"The IP address or hostname of the external system
that terminates incoming RESTCONF client
connections before forwarding them to this
server.";
}
leaf port {
type inet:port-number;
default "443";
description
"The port number that the external system listens
on for incoming RESTCONF client connections that
are forwarded to this server. The default HTTPS
port (443) is used, as expected for a RESTCONF
connection.";
}
}
container tcp-server-parameters {
description
"A wrapper around the TCP server parameters
to avoid name collisions.";
uses tcps:tcp-server-grouping {
refine "local-port" {
default "80";
description
"The RESTCONF server will listen on the IANA-
assigned well-known port value for 'http'
(80) if no value is specified.";
}
}
}
container http-server-parameters {
description
"A wrapper around the HTTP server parameters
to avoid name collisions.";
uses https:http-server-grouping;
}
container restconf-server-parameters {
description
"A wrapper around the RESTCONF server parameters
to avoid name collisions.";
uses rcs:restconf-server-grouping;
}
}
}
case https {
if-feature "https-listen";
container https {
description
"Configures RESTCONF server stack assuming that
TLS-termination is handled internally.";
container tcp-server-parameters {
description
"A wrapper around the TCP server parameters
to avoid name collisions.";
uses tcps:tcp-server-grouping {
refine "local-port" {
default "443";
description
"The RESTCONF server will listen on the IANA-
assigned well-known port value for 'https'
(443) if no value is specified.";
}
}
}
container tls-server-parameters {
description
"A wrapper around the TLS server parameters
to avoid name collisions.";
uses tlss:tls-server-grouping;
}
container http-server-parameters {
description
"A wrapper around the HTTP server parameters
to avoid name collisions.";
uses https:http-server-grouping;
}
container restconf-server-parameters {
description
"A wrapper around the RESTCONF server parameters
to avoid name collisions.";
uses rcs:restconf-server-grouping;
}
}
}
}
}
grouping restconf-server-callhome-stack-grouping {
description
"A reusable grouping for configuring a RESTCONF server
'call-home' protocol stack, for a single connection.";
choice transport {
mandatory true;
description
"Selects between available transports. This is a
'choice' statement so as to support additional
transport options to be augmented in.";
case https {
if-feature "https-listen";
container https {
description
"Configures RESTCONF server stack assuming that
TLS-termination is handled internally.";
container tcp-client-parameters {
description
"A wrapper around the TCP client parameters
to avoid name collisions.";
uses tcpc:tcp-client-grouping {
refine "remote-port" {
default "4336";
description
"The RESTCONF server will attempt to
connect to the IANA-assigned well-known
port for 'restconf-ch-tls' (4336) if no
value is specified.";
}
}
}
container tls-server-parameters {
description
"A wrapper around the TLS server parameters
to avoid name collisions.";
uses tlss:tls-server-grouping;
}
container http-server-parameters {
description
"A wrapper around the HTTP server parameters
to avoid name collisions.";
uses https:http-server-grouping;
}
container restconf-server-parameters {
description
"A wrapper around the RESTCONF server parameters
to avoid name collisions.";
uses rcs:restconf-server-grouping;
}
}
}
}
}
grouping restconf-server-app-grouping {
description
"A reusable grouping for configuring a RESTCONF server
application that supports both 'listen' and 'call-home'
protocol stacks for a multiplicity of connections.";
container listen {
if-feature "http-listen or https-listen";
presence
"Identifies that the server has been configured to
listen for incoming client connections. This statement
is present so the mandatory descendant nodes do not
imply that this node must be configured.";
description
"Configures the RESTCONF server to listen for RESTCONF
client connections.";
list endpoint {
key "name";
min-elements 1;
description
"List of endpoints to listen for RESTCONF connections.";
leaf name {
type string;
description
"An arbitrary name for the RESTCONF listen endpoint.";
}
uses restconf-server-listen-stack-grouping;
}
}
container call-home {
if-feature "https-call-home";
presence
"Identifies that the server has been configured to initiate
call home connections. This statement is present so the
mandatory descendant nodes do not imply that this node
must be configured.";
description
"Configures the RESTCONF server to initiate the underlying
transport connection to RESTCONF clients.";
list restconf-client {
key "name";
min-elements 1;
description
"List of RESTCONF clients the RESTCONF server is to
maintain simultaneous call-home connections with.";
leaf name {
type string;
description
"An arbitrary name for the remote RESTCONF client.";
}
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 RESTCONF
client. Defining more than one enables high-
availability.";
leaf name {
type string;
description
"An arbitrary name for this endpoint.";
}
uses restconf-server-callhome-stack-grouping;
}
}
container connection-type {
description
"Indicates the RESTCONF server's preference for how the
RESTCONF connection is maintained.";
choice connection-type {
mandatory true;
description
"Selects between available connection types.";
case persistent-connection {
container persistent {
presence
"Indicates that a persistent connection is to be
maintained.";
description
"Maintain a persistent connection to the RESTCONF
client. If the connection goes down, immediately
start trying to reconnect to the RESTCONF server,
using the reconnection strategy.
This connection type minimizes any RESTCONF
client to RESTCONF server data-transfer delay,
albeit at the expense of holding resources
longer.";
}
}
case periodic-connection {
container periodic {
presence
"Indicates that a periodic connection is to be
maintained.";
description
"Periodically connect to the RESTCONF client.
This connection type increases resource
utilization, albeit with increased delay in
RESTCONF client to RESTCONF client interactions.
The RESTCONF client SHOULD gracefully close
the underlying TLS connection upon completing
planned activities. If the underlying TLS
connection is not closed gracefully, the
RESTCONF server MUST immediately attempt
to reestablish the connection.
In the case that the previous connection is
still active (i.e., the RESTCONF client has not
closed it yet), establishing a new connection
is NOT RECOMMENDED.";
leaf period {
type uint16;
units "minutes";
default "60";
description
"Duration of time between periodic connections.";
}
leaf anchor-time {
type yang:date-and-time {
// constrained to minute-level granularity
pattern '\d{4}-\d{2}-\d{2}T\d{2}:\d{2}'
+ '(Z|[\+\-]\d{2}:\d{2})';
}
description
"Designates a timestamp before or after which a
series of periodic connections are determined.
The periodic connections occur at a whole
multiple interval from the anchor time. For
example, for an anchor time is 15 minutes past
midnight and a period interval of 24 hours, then
a periodic connection will occur 15 minutes past
midnight everyday.";
}
leaf idle-timeout {
type uint16;
units "seconds";
default "120"; // two minutes
description
"Specifies the maximum number of seconds that
the underlying TCP session may remain idle.
A TCP 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.";
}
}
}
}
}
container reconnect-strategy {
description
"The reconnection strategy directs how a RESTCONF server
reconnects to a RESTCONF client after discovering its
connection to the client has dropped, even if due to a
reboot. The RESTCONF server starts with the specified
endpoint and tries to connect to it max-attempts times
before trying the next endpoint in the list (round
robin).";
leaf start-with {
type enumeration {
enum first-listed {
description
"Indicates that reconnections should start with
the first endpoint listed.";
}
enum last-connected {
description
"Indicates that reconnections should start with
the endpoint last connected to. If no previous
connection has ever been established, then the
first endpoint configured is used. RESTCONF
servers SHOULD be able to remember the last
endpoint connected to across reboots.";
}
enum random-selection {
description
"Indicates that reconnections should start with
a random endpoint.";
}
}
default "first-listed";
description
"Specifies which of the RESTCONF client's endpoints
the RESTCONF server should start with when trying
to connect to the RESTCONF client.";
}
leaf max-attempts {
type uint8 {
range "1..max";
}
default "3";
description
"Specifies the number times the RESTCONF server tries
to connect to a specific endpoint before moving on to
the next endpoint in the list (round robin).";
}
}
} // restconf-client
} // call-home
} // restconf-server-app-grouping
// Protocol accessible node for servers that implement this module.
container restconf-server {
uses restconf-server-app-grouping;
description
"Top-level container for RESTCONF server configuration.";
}
}
]]><CODE ENDS>Security ConsiderationsThe "ietf-restconf-client" YANG ModuleThe "ietf-restconf-client" YANG module defines data nodes
that are designed to be accessed via YANG based management
protocols, such as NETCONF and RESTCONF
. Both of these protocols have
mandatory-to-implement secure transport layers (e.g., SSH, TLS)
with mutual authentication.The NETCONF access control model (NACM)
provides the means to restrict access for particular users to a
pre-configured subset of all available protocol operations and
content.None of the readable data nodes in this YANG module are
considered sensitive or vulnerable in network environments.
The NACM "default-deny-all" extension has not been set for
any data nodes defined in this module.None of the writable data nodes in this YANG module are
considered sensitive or vulnerable in network environments.
The NACM "default-deny-write" extension has not been set for
any data nodes defined in this module.This module does not define any RPCs, actions, or notifications,
and thus the security consideration for such is not provided here.Please be aware that this module uses groupings defined in
other RFCs that define data nodes that do set the NACM "default-deny-all"
and "default-deny-write" extensions.The "ietf-restconf-server" YANG ModuleThe "ietf-restconf-server" YANG module defines data nodes
that are designed to be accessed via YANG based management
protocols, such as NETCONF and RESTCONF
. Both of these protocols have
mandatory-to-implement secure transport layers (e.g., SSH, TLS)
with mutual authentication.The NETCONF access control model (NACM)
provides the means to restrict access for particular users to a
pre-configured subset of all available protocol operations and
content.None of the readable data nodes in this YANG module are
considered sensitive or vulnerable in network environments.
The NACM "default-deny-all" extension has not been set for
any data nodes defined in this module.None of the writable data nodes in this YANG module are
considered sensitive or vulnerable in network environments.
The NACM "default-deny-write" extension has not been set for
any data nodes defined in this module.This module does not define any RPCs, actions, or notifications,
and thus the security consideration for such is not provided here.Please be aware that this module uses groupings defined in
other RFCs that define data nodes that do set the NACM "default-deny-all"
and "default-deny-write" extensions.IANA ConsiderationsThe "IETF XML" RegistryThis document registers two URIs in the "ns" subregistry of the IETF XML
Registry . Following the format in
, the following registrations are
requested:The "YANG Module Names" RegistryThis document registers two YANG modules in the
YANG Module Names registry .
Following the format in , the
following registrations are requested:ReferencesNormative ReferencesKey words for use in RFCs to Indicate Requirement LevelsIn many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK]Common YANG Data TypesThis document introduces a collection of common data types to be used with the YANG data modeling language. This document obsoletes RFC 6021.A YANG Data Model for SNMP ConfigurationThis document defines a collection of YANG definitions for configuring SNMP engines.The YANG 1.1 Data Modeling LanguageYANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols. This document describes the syntax and semantics of version 1.1 of the YANG language. YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects in the original specification. There are a small number of backward incompatibilities from YANG version 1. This document also specifies the YANG mappings to the Network Configuration Protocol (NETCONF).RESTCONF ProtocolThis document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF).NETCONF Call Home and RESTCONF Call HomeThis RFC presents NETCONF Call Home and RESTCONF Call Home, which enable a NETCONF or RESTCONF server to initiate a secure connection to a NETCONF or RESTCONF client, respectively.Ambiguity of Uppercase vs Lowercase in RFC 2119 Key WordsRFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.Informative ReferencesThe IETF XML RegistryThis document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas.Network Configuration Protocol (NETCONF)The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK]YANG Tree DiagramsThis document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language.Network Configuration Access Control ModelThe standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model.This document obsoletes RFC 6536.Network Management Datastore Architecture (NMDA)Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950.The Transport Layer Security (TLS) Protocol Version 1.3This document specifies version 1.3 of the Transport Layer Security (TLS) protocol. TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery.This document updates RFCs 5705 and 6066, and obsoletes RFCs 5077, 5246, and 6961. This document also specifies new requirements for TLS 1.2 implementations.Change Log00 to 01
Renamed "keychain" to "keystore".
01 to 02
Filled in previously missing 'ietf-restconf-client' module.
Updated the ietf-restconf-server module to accommodate new
grouping 'ietf-tls-server-grouping'.
02 to 03
Refined use of tls-client-grouping to add a must statement
indicating that the TLS client must specify a client-certificate.
Changed restconf-client??? to be a grouping (not a container).
03 to 04
Added RFC 8174 to Requirements Language Section.
Replaced refine statement in ietf-restconf-client
to add a mandatory true.
Added refine statement in ietf-restconf-server
to add a must statement.
Now there are containers and groupings, for both the
client and server models.
Now tree diagrams reference ietf-netmod-yang-tree-diagrams
Updated examples to inline key and certificates (no longer
a leafref to keystore)
04 to 05
Now tree diagrams reference ietf-netmod-yang-tree-diagrams
Updated examples to inline key and certificates (no longer
a leafref to keystore)
05 to 06
Fixed change log missing section issue.
Updated examples to match latest updates to the crypto-types,
trust-anchors, and keystore drafts.
Reduced line length of the YANG modules to fit within 69 columns.
06 to 07
removed "idle-timeout" from "persistent" connection config.
Added "random-selection" for reconnection-strategy's "starts-with" enum.
Replaced "connection-type" choice default (persistent) with "mandatory true".
Reduced the periodic-connection's "idle-timeout" from 5 to 2 minutes.
Replaced reconnect-timeout with period/anchor-time combo.
07 to 08
Modified examples to be compatible with new crypto-types algs
08 to 09
Corrected use of "mandatory true" for "address" leafs.
Updated examples to reflect update to groupings defined in the keystore draft.
Updated to use groupings defined in new TCP and HTTP drafts.
Updated copyright date, boilerplate template, affiliation, and folding algorithm.
09 to 10
Reformatted YANG modules.
10 to 11
Adjusted for the top-level "demux container" added to groupings
imported from other modules.
Added "must" expressions to ensure that keepalives are not configured
for "periodic" connections.
Updated the boilerplate text in module-level "description" statement
to match copyeditor convention.
Moved "expanded" tree diagrams to the Appendix.
11 to 12
Removed the 'must' statement limiting keepalives in periodic
connections.
Updated models and examples to reflect removal of the "demux"
containers in the imported models.
Updated the "periodic-connnection" description statements to
better describe behavior when connections are not closed
gracefully.
Updated text to better reference where certain examples come from
(e.g., which Section in which draft).
In the server model, commented out the "must 'pinned-ca-certs or
pinned-client-certs'" statement to reflect change made in the
TLS draft whereby the trust anchors MAY be defined externally.
Replaced the 'listen', 'initiate', and 'call-home' features
with boolean expressions.
12 to 13
Updated to reflect changes in trust-anchors drafts
(e.g., s/trust-anchors/truststore/g + s/pinned.//)
In ietf-restconf-server, Added 'http-listen' (not https-listen) choice, to support
case when server is behind a TLS-terminator.
Refactored server module to be more like other 'server' models. If folks like it, will
also apply to the client model, as well as to both the netconf client/server models. Now
the 'restconf-server-grouping' is just the RC-specific bits (i.e., the "demux" container
minus the container), 'restconf-server-[listen|callhome]-stack-grouping' is the protocol
stack for a single connection, and 'restconf-server-app-grouping' is effectively what
was before (both listen+callhome for many inbound/outbound endpoints).
13 to 14
Updated examples to reflect ietf-crypto-types change
(e.g., identities --> enumerations)
Adjusting from change in TLS client model (removing the top-level
'certificate' container).
Added "external-endpoint" to the "http-listen" choice in ietf-restconf-server.
14 to 15
Added missing "or https-listen" clause in a "must" expression.
Refactored the client module similar to how the server module was refactored in -13. Now
the 'restconf-client-grouping' is just the RC-specific bits, the
'restconf-client-[initiate|listen]-stack-grouping' is the protocol
stack for a single connection, and 'restconf-client-app-grouping' is effectively what
was before (both listen+callhome for many inbound/outbound endpoints).
15 to 16
Added refinement to make "cert-to-name/fingerprint" be mandatory false.
Commented out refinement to "tls-server-grouping/client-authentication"
until a better "must" expression is defined.
Updated restconf-client example to reflect that http-client-grouping no
longer has a "protocol-version" leaf.
16 to 17
Updated examples to include the "*-key-format" nodes.
Updated examples to remove the "required" nodes.
17 to 18
Updated examples to reflect new "bag" addition to truststore.
18 to 19
Updated examples to remove the 'algorithm' nodes.
Updated examples to reflect the new TLS keepalives structure.
Removed the 'protocol-versions' node from the restconf-server examples.
Added a "Note to Reviewers" note to first page.
19 to 20
Moved and changed "must" statement so that either TLS *or* HTTP auth must be configured.
Expanded "Data Model Overview section(s) [remove "wall" of tree diagrams].
Updated the Security Considerations section.
20 to 21
Cleaned up titles in the IANA Consideratons section
Fixed issues found by the SecDir review of the "keystore" draft.
21 to 22
Addressed comments raised by YANG Doctor in the ct/ts/ks drafts.
22 to 23
Further clarified why some 'presence' statements are present.
Addressed nits found in YANG Doctor reviews.
Aligned modules with `pyang -f` formatting.
23 to 24
Removed Appendix A with fully-expanded tree diagrams.
Replaced "base64encodedvalue==" with "BASE64VALUE=" in examples.
Minor editorial nits
24 to 25
Fixed up the 'WG Web' and 'WG List' lines in YANG module(s)
Fixed up copyright (i.e., s/Simplified/Revised/) in YANG module(s)
AcknowledgementsThe authors would like to thank for following for
lively discussions on list and in the halls (ordered
by first name):
Alan Luchuk,
Andy Bierman,
Balazs Kovacs,
Benoit Claise,
Bert Wijnen
David Lamparter,
Juergen Schoenwaelder,
Ladislav Lhotka,
Martin Bjoerklund,
Mehmet Ersue,
Phil Shafer,
Radek Krejci,
Ramkumar Dhanapal,
Sean Turner,
and Tom Petch.