A YANG Model for Transmission Control Protocol (TCP) Configuration
draft-ietf-tcpm-yang-tcp-06
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Active".
|
|
|---|---|---|---|
| Authors | Michael Scharf , Mahesh Jethanandani , Vishal Murgai | ||
| Last updated | 2022-05-04 (Latest revision 2022-02-03) | ||
| Replaces | draft-scharf-tcpm-yang-tcp | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Formats | |||
| Reviews |
TSVART Last Call review
by Gorry Fairhurst
Ready w/nits
SECDIR Last Call review
by Hilarie Orman
Has issues
OPSDIR Last Call review
by Gyan Mishra
Not ready
YANGDOCTORS Early review
by Ebben Aries
On the Right Track
|
||
| Additional resources | Mailing list discussion | ||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Yoshifumi Nishida | ||
| Shepherd write-up | Show Last changed 2022-02-07 | ||
| IESG | IESG state | Waiting for AD Go-Ahead::Revised I-D Needed | |
| Consensus boilerplate | Yes | ||
| Telechat date | (None) | ||
| Responsible AD | Martin Duke | ||
| Send notices to | nsd.ietf@gmail.com | ||
| IANA | IANA review state | IANA OK - Actions Needed | |
| IANA expert review state | Expert Reviews OK |
draft-ietf-tcpm-yang-tcp-06
TCPM M. Scharf
Internet-Draft Hochschule Esslingen
Intended status: Standards Track M. Jethanandani
Expires: 7 August 2022 Kloud Services
V. Murgai
Samsung
3 February 2022
A YANG Model for Transmission Control Protocol (TCP) Configuration
draft-ietf-tcpm-yang-tcp-06
Abstract
This document specifies a minimal YANG model for TCP on devices that
are configured by network management protocols. The YANG model
defines a container for all TCP connections and groupings of
authentication parameters that can be imported and used in TCP
implementations or by other models that need to configure TCP
parameters. The model also includes basic TCP statistics. The model
is compliant with Network Management Datastore Architecture (NMDA)
(RFC 8342).
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 7 August 2022.
Copyright Notice
Copyright (c) 2022 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
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Please review these documents carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
2.1. Note to RFC Editor . . . . . . . . . . . . . . . . . . . 4
3. YANG Module Overview . . . . . . . . . . . . . . . . . . . . 4
3.1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Model Design . . . . . . . . . . . . . . . . . . . . . . 6
3.3. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 6
4. TCP YANG Model . . . . . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
5.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 14
5.2. The YANG Module Names Registry . . . . . . . . . . . . . 15
6. Security Considerations . . . . . . . . . . . . . . . . . . . 15
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
7.1. Normative References . . . . . . . . . . . . . . . . . . 16
7.2. Informative References . . . . . . . . . . . . . . . . . 18
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 20
Appendix B. Examples . . . . . . . . . . . . . . . . . . . . . . 20
B.1. Keepalive Configuration . . . . . . . . . . . . . . . . . 20
B.2. TCP-AO Configuration . . . . . . . . . . . . . . . . . . 21
Appendix C. Complete Tree Diagram . . . . . . . . . . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction
The Transmission Control Protocol (TCP) [I-D.ietf-tcpm-rfc793bis] is
used by many applications in the Internet, including control and
management protocols. As such, TCP is implemented on network
elements that can be configured via network management protocols such
as NETCONF [RFC6241] or RESTCONF [RFC8040].
This document specifies a minimal YANG 1.1 [RFC7950] model for
configuring TCP on network elements that support YANG. This YANG
module is compliant with Network Management Datastore Architecture
(NMDA) [RFC8342].
The YANG module has a narrow scope and focuses on a subset of
fundamental TCP functions and basic statistics. It defines a
container for TCP connection that includes definitions from YANG
Groupings for TCP Clients and TCP Servers
[I-D.ietf-netconf-tcp-client-server]. This model adheres to the
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recommendation in BGP/MPLS IP Virtual Private Networks [RFC4364] as
it allows enabling of TCP-AO [RFC5925], and accommodates the
installed base that makes use of MD5. The module can be augmented or
updated to address more advanced or implementation-specific TCP
features in the future.
Many protocol stacks on IP hosts use other methods to configure TCP,
such as operating system configuration or policies. Many TCP/IP
stacks cannot be configured by network management protocols such as
NETCONF [RFC6241] or RESTCONF [RFC8040]. Moreover, many existing
TCP/IP stacks do not use YANG data models. Such TCP implementations
often have other means to configure the parameters listed in this
document. Such other means are outside the scope of this document.
This specification is orthogonal to the Management Information Base
(MIB) for the Transmission Control Protocol (TCP) [RFC4022]. The
basic statistics defined in this document follow the model of the TCP
MIB. An TCP Extended Statistics MIB [RFC4898] is also available, but
this document does not cover such extended statistics. The YANG
module also omits some selected parameters included in TCP MIB, most
notably the configured Retransmission Timeout (RTO) algorithm. This
is conscious decision as these parameters hardly matter in a state-
of-the-art TCP implementation. It would also be possible also to
translate a MIB into a YANG module, for instance using Translation of
Structure of Management Information Version 2 (SMIv2) MIB Modules to
YANG Modules [RFC6643]. However, this approach is not used in this
document, because a translated model would not be up-to-date.
There are other existing TCP-related YANG models, which are
orthogonal to this specification. Examples are:
* TCP header attributes are modeled in other security-related
models, such as YANG Data Model for Network Access Control Lists
(ACLs) [RFC8519], Distributed Denial-of-Service Open Thread
Signaling (DOTS) Data Channel Specification [RFC8783], or I2NSF
Capability YANG Data Model [I-D.ietf-i2nsf-capability-data-model].
* TCP-related configuration of a NAT (e.g., NAT44, NAT64,
Destination NAT) is defined in A YANG Module for Network Address
Translation (NAT) and Network Prefix Translation (NPT) [RFC8512]
and A YANG Data Model for Dual-Stack Lite (DS-Lite) [RFC8513].
* TCP-AO and TCP MD5 configuration for Layer 3 VPNs is modeled in A
Layer 3 VPN Network YANG Model [I-D.ietf-opsawg-l3sm-l3nm]. This
model assumes that TCP-AO specific parameters are preconfigured in
addition to the keychain parameters. This issue is further
discussed below.
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2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2.1. Note to RFC Editor
This document uses several placeholder values throughout the
document. Please replace them as follows and remove this note before
publication.
RFC XXXX, where XXXX is the number assigned to this document at the
time of publication.
2022-02-04 with the actual date of the publication of this document.
3. YANG Module Overview
3.1. Scope
TCP is implemented on different system architectures. As a result,
there are many different and often implementation-specific ways to
configure parameters of the TCP engine. In addition, in many TCP/IP
stacks configuration exists for different scopes:
* Global configuration: Many TCP implementations have configuration
parameters that affect all TCP connections. Typical examples
include enabling or disabling optional protocol features.
* Interface configuration: It can be useful to use different TCP
parameters on different interfaces, e.g., different device ports
or IP interfaces. In that case, TCP parameters can be part of the
interface configuration. Typical examples are the Maximum Segment
Size (MSS) or configuration related to hardware offloading.
* Connection parameters: Many implementations have means to
influence the behavior of each TCP connection, e.g., on the
programming interface used by applications. Typical examples are
socket options in the socket API, such as disabling the Nagle
algorithm by TCP_NODELAY. If an application uses such an
interface, it is possible that the configuration of the
application or application protocol includes TCP-related
parameters. An example is the BGP YANG Model for Service Provider
Networks [I-D.ietf-idr-bgp-model].
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* Policies: Setting of TCP parameters can also be part of system
policies, templates, or profiles. An example would be the
preferences defined in An Abstract Application Layer Interface to
Transport Services [I-D.ietf-taps-interface].
As a result, there is no ground truth for setting certain TCP
parameters, and traditionally different TCP implementation have used
different modeling approaches. For instance, one implementation may
define a given configuration parameter globally, while another one
uses per-interface settings, and both approaches work well for the
corresponding use cases. Also, different systems may use different
default values. In addition, TCP can be implemented in different
ways and design choices by the protocol engine often affect
configuration options.
Nonetheless, a number of TCP stack parameters require configuration
by YANG models. This document therefore defines a minimal YANG model
with fundamental parameters directly following from TCP standards.
An important use case is the TCP configuration on network elements
such as routers, which often use YANG data models. The model
therefore specifies TCP parameters that are important on such TCP
stacks.
This in particular applies to the support of TCP-AO [RFC5925]. TCP
Authentication Option (TCP-AO) is used on routers to secure routing
protocols such as BGP. In that case, a YANG model for TCP-AO
configuration is required. The model defined in this document
includes the required parameters for TCP-AO configuration, such as
the values of SendID and RecvID. The keychain for TCP-AO can be
modeled by the YANG Data Model for Key Chains [RFC8177]. The
groupings defined in this document can be imported and used as part
of such a preconfiguration.
Given an installed base, the model also allows enabling of the legacy
TCP MD5 [RFC2385] signature option. As the TCP MD5 signature option
is obsoleted by TCP-AO, it is strongly RECOMMENDED to use TCP-AO.
Similar to the TCP MIB [RFC4022], this document also specifies basic
statistics and a TCP connection table.
* Statistics: Counters for the number of active/passive opens, sent
and received segments, errors, and possibly other detailed
debugging information
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* TCP connection table: Access to status information for all TCP
connections. Note, the connection table is modeled as a list that
is read-writeable, even though a connection cannot be created by
adding entries to the table. Similarly, deletion of connections
from this list is implementation-specific.
This allows implementations of TCP MIB [RFC4022] to migrate to the
YANG model defined in this memo. Note that the TCP MIB does not
include means to reset statistics, which are defined in this
document. This is not a major addition, as a reset can simply be
implemented by storing offset values for the counters.
This version of the module does not cover Multipath TCP [RFC8684].
3.2. Model Design
The YANG model defined in this document includes definitions from the
YANG Groupings for TCP Clients and TCP Servers
[I-D.ietf-netconf-tcp-client-server]. Similar to that model, this
specification defines YANG groupings. This allows reuse of these
groupings in different YANG data models. It is intended that these
groupings will be used either standalone or for TCP-based protocols
as part of a stack of protocol-specific configuration models. An
example could be the BGP YANG Model for Service Provider Networks
[I-D.ietf-idr-bgp-model].
3.3. Tree Diagram
This section provides an abridged tree diagram for the YANG module
defined in this document. Annotations used in the diagram are
defined in YANG Tree Diagrams [RFC8340].
module: ietf-tcp
+--rw tcp!
+--rw connections
| ...
+--ro statistics {statistics}?
...
4. TCP YANG Model
This YANG module references The TCP Authentication Option [RFC5925],
Protection of BGP Sessions via the TCP MD5 Signature [RFC2385],
Transmission Control Protocol (TCP) Specification
[I-D.ietf-tcpm-rfc793bis], and imports Common YANG Data Types
[RFC6991], The NETCONF Access Control Model [RFC8341], and YANG
Groupings for TCP Clients and TCP Servers
[I-D.ietf-netconf-tcp-client-server].
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<CODE BEGINS> file "ietf-tcp@2022-02-04.yang"
module ietf-tcp {
yang-version "1.1";
namespace "urn:ietf:params:xml:ns:yang:ietf-tcp";
prefix "tcp";
import ietf-yang-types {
prefix "yang";
reference
"RFC 6991: Common YANG Data Types.";
}
import ietf-tcp-common {
prefix "tcpcmn";
reference
"I-D.ietf-netconf-tcp-client-server: YANG Groupings for TCP
Clients and TCP Servers.";
}
import ietf-inet-types {
prefix "inet";
reference
"RFC 6991: Common YANG Data Types.";
}
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Access Control Model";
}
organization
"IETF TCPM Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/tcpm/about>
WG List: <tcpm@ietf.org>
Authors: Michael Scharf (michael.scharf at hs-esslingen dot de)
Mahesh Jethanandani (mjethanandani at gmail dot com)
Vishal Murgai (vmurgai at gmail dot com)";
description
"This module focuses on fundamental TCP functions and basic
statistics. The model can be augmented to address more advanced
or implementation specific TCP features.
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
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without modification, is permitted pursuant to, and subject to
the license terms contained in, the Simplified BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself
for full legal notices.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
'MAY', and 'OPTIONAL' in this document are to be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here.";
revision "2022-02-04" {
description
"Initial Version";
reference
"RFC XXXX, A YANG Model for Transmission Control Protocol (TCP)
Configuration.";
}
// Features
feature statistics {
description
"This implementation supports statistics reporting.";
}
// TCP-AO Groupings
grouping ao {
leaf enable-ao {
type boolean;
default "false";
description
"When set to true, TCP-Authentication Option (TCP-AO) is
enabled.";
}
leaf send-id {
type uint8 {
range "0..max";
}
must "../enable-ao = 'true'";
description
"The SendID is inserted as the KeyID of the TCP-AO option
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of outgoing segments. The SendID must match the RecvID
at the other endpoint.";
reference
"RFC 5925: The TCP Authentication Option, Section 3.1.";
}
leaf recv-id {
type uint8 {
range "0..max";
}
must "../enable-ao = 'true'";
description
"The RecvID is matched against the TCP-AO KeyID of incoming
segments. The RecvID must match the SendID at the other
endpoint.";
reference
"RFC 5925: The TCP Authentication Option, Section 3.1.";
}
leaf include-tcp-options {
type boolean;
must "../enable-ao = 'true'";
default true;
description
"When set to true, TCP options are included in MAC
calculation.";
reference
"RFC 5925: The TCP Authentication Option, Section 3.1.";
}
leaf accept-key-mismatch {
type boolean;
must "../enable-ao = 'true'";
description
"Accept, when set to true, TCP segments with a Master Key
Tuple (MKT) that is not configured.";
reference
"RFC 5925: The TCP Authentication Option, Section 7.3.";
}
description
"Authentication Option (AO) for TCP.";
reference
"RFC 5925: The TCP Authentication Option.";
}
// MD5 grouping
grouping md5 {
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description
"Grouping for use in authenticating TCP sessions using MD5.";
reference
"RFC 2385: Protection of BGP Sessions via the TCP MD5
Signature.";
leaf enable-md5 {
type boolean;
default "false";
description
"Enables, when set to true, support of MD5 to authenticate a
TCP session. As the TCP MD5 signature option is obsoleted by
TCP-AO, it is strongly RECOMMENDED to use TCP-AO instead.";
}
}
// TCP configuration
container tcp {
presence "The container for TCP configuration.";
description
"TCP container.";
container connections {
list connection {
key "local-address remote-address local-port remote-port";
leaf local-address {
type inet:ip-address;
description
"Identifies the address that is used by the local
endpoint for the connection, and is one of the four
elements that form the connection identifier.";
}
leaf remote-address {
type inet:ip-address;
description
"Identifies the address that is used by the remote
endpoint for the connection, and is one of the four
elements that form the connection identifier.";
}
leaf local-port {
type inet:port-number;
description
"Identifies the local TCP port used for the connection,
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and is one of the four elements that form the
connection identifier.";
}
leaf remote-port {
type inet:port-number;
description
"Identifies the remote TCP port used for the connection,
and is one of the four elements that form the
connection identifier.";
}
container common {
uses tcpcmn:tcp-common-grouping;
choice authentication {
case ao {
uses ao;
description
"Use TCP-AO to secure the connection.";
}
case md5 {
uses md5;
description
"Use TCP-MD5 to secure the connection.";
}
description
"Choice of TCP authentication.";
}
description
"Common definitions of TCP configuration. This includes
parameters such as how to secure the connection,
that can be part of either the client or server.";
}
description
"List of TCP connections with their parameters. The list
is modeled as writeable, but implementations may not
allow creation of new TCP connections by adding entries to
the list. Furthermore, the behavior upon removal is
implementation-specific. Implementations may support
closing or resetting a TCP connection upon an operation
that removes the entry from the list.";
}
description
"A container of all TCP connections.";
}
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container statistics {
if-feature statistics;
config false;
leaf active-opens {
type yang:counter32;
description
"The number of times that TCP connections have made a
direct transition to the SYN-SENT state from the CLOSED
state.";
reference
"I-D.ietf-tcpm-rfc793bis: Transmission Control Protocol
(TCP) Specification.";
}
leaf passive-opens {
type yang:counter32;
description
"The number of times TCP connections have made a direct
transition to the SYN-RCVD state from the LISTEN state.";
reference
"I-D.ietf-tcpm-rfc793bis: Transmission Control Protocol
(TCP) Specification.";
}
leaf attempt-fails {
type yang:counter32;
description
"The number of times that TCP connections have made a
direct transition to the CLOSED state from either the
SYN-SENT state or the SYN-RCVD state, plus the number of
times that TCP connections have made a direct transition
to the LISTEN state from the SYN-RCVD state.";
reference
"I-D.ietf-tcpm-rfc793bis: Transmission Control Protocol
(TCP) Specification.";
}
leaf establish-resets {
type yang:counter32;
description
"The number of times that TCP connections have made a
direct transition to the CLOSED state from either the
ESTABLISHED state or the CLOSE-WAIT state.";
reference
"I-D.ietf-tcpm-rfc793bis: Transmission Control Protocol
(TCP) Specification.";
}
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leaf currently-established {
type yang:gauge32;
description
"The number of TCP connections for which the current state
is either ESTABLISHED or CLOSE-WAIT.";
reference
"I-D.ietf-tcpm-rfc793bis: Transmission Control Protocol
(TCP) Specification.";
}
leaf in-segments {
type yang:counter64;
description
"The total number of segments received, including those
received in error. This count includes segments received
on currently established connections.";
reference
"I-D.ietf-tcpm-rfc793bis: Transmission Control Protocol
(TCP) Specification.";
}
leaf out-segments {
type yang:counter64;
description
"The total number of segments sent, including those on
current connections but excluding those containing only
retransmitted octets.";
reference
"I-D.ietf-tcpm-rfc793bis: Transmission Control Protocol
(TCP) Specification.";
}
leaf retransmitted-segments {
type yang:counter32;
description
"The total number of segments retransmitted; that is, the
number of TCP segments transmitted containing one or more
previously transmitted octets.";
reference
"I-D.ietf-tcpm-rfc793bis: Transmission Control Protocol
(TCP) Specification.";
}
leaf in-errors {
type yang:counter32;
description
"The total number of segments received in error (e.g., bad
TCP checksums).";
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reference
"I-D.ietf-tcpm-rfc793bis: Transmission Control Protocol
(TCP) Specification.";
}
leaf out-resets {
type yang:counter32;
description
"The number of TCP segments sent containing the RST flag.";
reference
"I-D.ietf-tcpm-rfc793bis: Transmission Control Protocol
(TCP) Specification.";
}
action reset {
nacm:default-deny-all;
description
"Reset statistics action command.";
input {
leaf reset-at {
type yang:date-and-time;
description
"Time when the reset action needs to be
executed.";
}
}
output {
leaf reset-finished-at {
type yang:date-and-time;
description
"Time when the reset action command completed.";
}
}
}
description
"Statistics across all connections.";
}
}
}
<CODE ENDS>
5. IANA Considerations
5.1. The IETF XML Registry
This document registers an URI in the "ns" subregistry of the IETF
XML Registry [RFC3688]. Following the format in IETF XML Registry
[RFC3688], the following registration is requested:
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URI: urn:ietf:params:xml:ns:yang:ietf-tcp
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
5.2. The YANG Module Names Registry
This document registers a YANG module in the "YANG Module Names"
registry YANG - A Data Modeling Language [RFC6020]. Following the
format in YANG - A Data Modeling Language [RFC6020], the following
registration is requested:
name: ietf-tcp
namespace: urn:ietf:params:xml:ns:yang:ietf-tcp
prefix: tcp
reference: RFC XXXX
The registration is not maintained by IANA.
6. Security Considerations
The YANG module specified in this document defines a schema for data
that is designed to be accessed via network management protocols such
as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer
is the secure transport layer, and the mandatory-to-implement secure
transport is Secure Shell (SSH) described in Using the NETCONF
protocol over SSH [RFC6242]. The lowest RESTCONF layer is HTTPS, and
the mandatory-to-implement secure transport is TLS [RFC8446].
The Network Configuration Access Control Model (NACM) [RFC8341]
provides the means to restrict access for particular NETCONF or
RESTCONF users to a preconfigured subset of all available NETCONF or
RESTCONF protocol operations and content.
There are a number of data nodes defined in this YANG module that are
writable/creatable/deletable (i.e., "config true", which is the
default). These data nodes may be considered sensitive or vulnerable
in some network environments. Write operations (e.g., edit-config)
to these data nodes without proper protection can have a negative
effect on network operations. These are the subtrees and data nodes
and their sensitivity/vulnerability:
* Common configuration included from NETCONF Client and Server
Models [I-D.ietf-netconf-tcp-client-server]. Unrestricted access
to all the nodes, e.g., keepalive idle-timer, can cause
connections to fail or to timeout prematurely.
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* Authentication configuration. Unrestricted access to the nodes
under authentication configuration can prevent the use of
authenticated communication and cause connection setups to fail.
This can result in massive security vulnerabilities and service
disruption for the traffic requiring authentication.
Some of the readable data nodes in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus
important to control read access (e.g., via get, get-config, or
notification) to these data nodes. These are the subtrees and data
nodes and their sensitivity/vulnerability:
* Unrestricted access to connection information of the client or
server can be used by a malicious user to launch an attack, e.g.
MITM.
* Similarly, unrestricted access to statistics of the client or
server can be used by a malicious user to exploit any
vulnerabilities of the system.
Some of the RPC operations in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus
important to control access to these operations. These are the
operations and their sensitivity/vulnerability:
* The YANG module allows for the statistics to be cleared by
executing the reset action. This action should be restricted to
users with the right permission.
The module specified in this document supports MD5 to basically
accommodate the installed BGP base. MD5 suffers from the security
weaknesses discussed in Section 2 of RFC 6151 [RFC6151] or
Section 2.1 of RFC 6952 [RFC6952].
7. References
7.1. Normative References
[I-D.ietf-netconf-tcp-client-server]
Watsen, K. and M. Scharf, "YANG Groupings for TCP Clients
and TCP Servers", Work in Progress, Internet-Draft, draft-
ietf-netconf-tcp-client-server-11, 14 December 2021,
<https://www.ietf.org/archive/id/draft-ietf-netconf-tcp-
client-server-11.txt>.
[I-D.ietf-tcpm-rfc793bis]
Eddy, W. M., "Transmission Control Protocol (TCP)
Specification", Work in Progress, Internet-Draft, draft-
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ietf-tcpm-rfc793bis-25, 7 September 2021,
<https://www.ietf.org/archive/id/draft-ietf-tcpm-
rfc793bis-25.txt>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2385] Heffernan, A., "Protection of BGP Sessions via the TCP MD5
Signature Option", RFC 2385, DOI 10.17487/RFC2385, August
1998, <https://www.rfc-editor.org/info/rfc2385>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP
Authentication Option", RFC 5925, DOI 10.17487/RFC5925,
June 2010, <https://www.rfc-editor.org/info/rfc5925>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/info/rfc6242>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
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[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8177] Lindem, A., Ed., Qu, Y., Yeung, D., Chen, I., and J.
Zhang, "YANG Data Model for Key Chains", RFC 8177,
DOI 10.17487/RFC8177, June 2017,
<https://www.rfc-editor.org/info/rfc8177>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/info/rfc8341>.
[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
and R. Wilton, "Network Management Datastore Architecture
(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
<https://www.rfc-editor.org/info/rfc8342>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>.
7.2. Informative References
[I-D.ietf-i2nsf-capability-data-model]
Hares, S., Jeong, J. (., Kim, J. (., Moskowitz, R., and Q.
Lin, "I2NSF Capability YANG Data Model", Work in Progress,
Internet-Draft, draft-ietf-i2nsf-capability-data-model-22,
22 January 2022, <https://www.ietf.org/archive/id/draft-
ietf-i2nsf-capability-data-model-22.txt>.
[I-D.ietf-idr-bgp-model]
Jethanandani, M., Patel, K., Hares, S., and J. Haas, "BGP
YANG Model for Service Provider Networks", Work in
Progress, Internet-Draft, draft-ietf-idr-bgp-model-12, 25
October 2021, <https://www.ietf.org/archive/id/draft-ietf-
idr-bgp-model-12.txt>.
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[I-D.ietf-opsawg-l3sm-l3nm]
Barguil, S., Dios, O. G. D., Boucadair, M., Munoz, L. A.,
and A. Aguado, "A Layer 3 VPN Network YANG Model", Work in
Progress, Internet-Draft, draft-ietf-opsawg-l3sm-l3nm-18,
8 October 2021, <https://www.ietf.org/archive/id/draft-
ietf-opsawg-l3sm-l3nm-18.txt>.
[I-D.ietf-taps-interface]
Trammell, B., Welzl, M., Enghardt, T., Fairhurst, G.,
Kuehlewind, M., Perkins, C., Tiesel, P. S., Wood, C. A.,
Pauly, T., and K. Rose, "An Abstract Application Layer
Interface to Transport Services", Work in Progress,
Internet-Draft, draft-ietf-taps-interface-14, 3 January
2022, <https://www.ietf.org/archive/id/draft-ietf-taps-
interface-14.txt>.
[I-D.ietf-tcpm-ao-test-vectors]
Touch, J. and J. Kuusisaari, "TCP-AO Test Vectors", Work
in Progress, Internet-Draft, draft-ietf-tcpm-ao-test-
vectors-06, 30 January 2022,
<https://www.ietf.org/archive/id/draft-ietf-tcpm-ao-test-
vectors-06.txt>.
[RFC4022] Raghunarayan, R., Ed., "Management Information Base for
the Transmission Control Protocol (TCP)", RFC 4022,
DOI 10.17487/RFC4022, March 2005,
<https://www.rfc-editor.org/info/rfc4022>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <https://www.rfc-editor.org/info/rfc4364>.
[RFC4898] Mathis, M., Heffner, J., and R. Raghunarayan, "TCP
Extended Statistics MIB", RFC 4898, DOI 10.17487/RFC4898,
May 2007, <https://www.rfc-editor.org/info/rfc4898>.
[RFC6151] Turner, S. and L. Chen, "Updated Security Considerations
for the MD5 Message-Digest and the HMAC-MD5 Algorithms",
RFC 6151, DOI 10.17487/RFC6151, March 2011,
<https://www.rfc-editor.org/info/rfc6151>.
[RFC6643] Schoenwaelder, J., "Translation of Structure of Management
Information Version 2 (SMIv2) MIB Modules to YANG
Modules", RFC 6643, DOI 10.17487/RFC6643, July 2012,
<https://www.rfc-editor.org/info/rfc6643>.
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[RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of
BGP, LDP, PCEP, and MSDP Issues According to the Keying
and Authentication for Routing Protocols (KARP) Design
Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013,
<https://www.rfc-editor.org/info/rfc6952>.
[RFC8512] Boucadair, M., Ed., Sivakumar, S., Jacquenet, C.,
Vinapamula, S., and Q. Wu, "A YANG Module for Network
Address Translation (NAT) and Network Prefix Translation
(NPT)", RFC 8512, DOI 10.17487/RFC8512, January 2019,
<https://www.rfc-editor.org/info/rfc8512>.
[RFC8513] Boucadair, M., Jacquenet, C., and S. Sivakumar, "A YANG
Data Model for Dual-Stack Lite (DS-Lite)", RFC 8513,
DOI 10.17487/RFC8513, January 2019,
<https://www.rfc-editor.org/info/rfc8513>.
[RFC8519] Jethanandani, M., Agarwal, S., Huang, L., and D. Blair,
"YANG Data Model for Network Access Control Lists (ACLs)",
RFC 8519, DOI 10.17487/RFC8519, March 2019,
<https://www.rfc-editor.org/info/rfc8519>.
[RFC8684] Ford, A., Raiciu, C., Handley, M., Bonaventure, O., and C.
Paasch, "TCP Extensions for Multipath Operation with
Multiple Addresses", RFC 8684, DOI 10.17487/RFC8684, March
2020, <https://www.rfc-editor.org/info/rfc8684>.
[RFC8783] Boucadair, M., Ed. and T. Reddy.K, Ed., "Distributed
Denial-of-Service Open Threat Signaling (DOTS) Data
Channel Specification", RFC 8783, DOI 10.17487/RFC8783,
May 2020, <https://www.rfc-editor.org/info/rfc8783>.
Appendix A. Acknowledgements
Michael Scharf was supported by the StandICT.eu project, which is
funded by the European Commission under the Horizon 2020 Programme.
The following persons have contributed to this document by reviews:
Mohamed Boucadair, and Tom Petch.
Appendix B. Examples
B.1. Keepalive Configuration
This particular example demonstrates how both a particular connection
can be configured for keepalives.
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NOTE: '\' line wrapping per RFC 8792
<?xml version="1.0" encoding="UTF-8"?>
<!--
This example shows how TCP keepalive can be configured for
a given connection. An idle connection is dropped after
idle-time + (max-probes * probe-interval).
-->
<tcp
xmlns="urn:ietf:params:xml:ns:yang:ietf-tcp">
<connections>
<connection>
<local-address>192.0.2.1</local-address>
<remote-address>192.0.2.2</remote-address>
<local-port>1025</local-port>
<remote-port>80</remote-port>
<common>
<keepalives>
<idle-time>5</idle-time>
<max-probes>5</max-probes>
<probe-interval>10</probe-interval>
</keepalives>
</common>
</connection>
</connections>
</tcp>
B.2. TCP-AO Configuration
The following example demonstrates how to model a TCP-AO [RFC5925]
configuration for the example in TCP-AO Test Vectors
[I-D.ietf-tcpm-ao-test-vectors].
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NOTE: '\' line wrapping per RFC 8792
<?xml version="1.0" encoding="UTF-8"?>
<!--
This example sets TCP-AO configuration parameters as
demonstrated by examples in draft-ietf-tcpm-ao-test-vectors.
-->
<tcp
xmlns="urn:ietf:params:xml:ns:yang:ietf-tcp">
<connections>
<connection>
<local-address>fd00::1</local-address>
<remote-address>fd00::2</remote-address>
<local-port>1025</local-port>
<remote-port>179</remote-port>
<common>
<enable-ao>true</enable-ao>
<send-id>61</send-id>
<recv-id>84</recv-id>
</common>
</connection>
</connections>
</tcp>
<key-chains
xmlns="urn:ietf:params:xml:ns:yang:ietf-key-chain">
<key-chain>
<name>ao-config</name>
<description>"An example for TCP-AO configuration."</description>\
<key>
<key-id>61</key-id>
<crypto-algorithm>hmac-sha-1</crypto-algorithm>
<key-string>
<keystring>testvector</keystring>
</key-string>
</key>
<key>
<key-id>84</key-id>
<crypto-algorithm>hmac-sha-1</crypto-algorithm>
<key-string>
<keystring>testvector</keystring>
</key-string>
</key>
</key-chain>
</key-chains>
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Appendix C. Complete Tree Diagram
Here is the complete tree diagram for the TCP YANG model.
module: ietf-tcp
+--rw tcp!
+--rw connections
| +--rw connection*
| [local-address remote-address local-port remote-port]
| +--rw local-address inet:ip-address
| +--rw remote-address inet:ip-address
| +--rw local-port inet:port-number
| +--rw remote-port inet:port-number
| +--rw common
| +--rw keepalives!
| | +--rw idle-time uint16
| | +--rw max-probes uint16
| | +--rw probe-interval uint16
| +--rw (authentication)?
| +--:(ao)
| | +--rw enable-ao? boolean
| | +--rw send-id? uint8
| | +--rw recv-id? uint8
| | +--rw include-tcp-options? boolean
| | +--rw accept-key-mismatch? boolean
| +--:(md5)
| +--rw enable-md5? boolean
+--ro statistics {statistics}?
+--ro active-opens? yang:counter32
+--ro passive-opens? yang:counter32
+--ro attempt-fails? yang:counter32
+--ro establish-resets? yang:counter32
+--ro currently-established? yang:gauge32
+--ro in-segments? yang:counter64
+--ro out-segments? yang:counter64
+--ro retransmitted-segments? yang:counter32
+--ro in-errors? yang:counter32
+--ro out-resets? yang:counter32
+---x reset
+---w input
| +---w reset-at? yang:date-and-time
+--ro output
+--ro reset-finished-at? yang:date-and-time
Authors' Addresses
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Michael Scharf
Hochschule Esslingen - University of Applied Sciences
Flandernstr. 101
73732 Esslingen
Germany
Email: michael.scharf@hs-esslingen.de
Mahesh Jethanandani
Kloud Services
Email: mjethanandani@gmail.com
Vishal Murgai
Samsung
Email: vmurgai@gmail.com
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