RTGWG F. Zheng
Internet-Draft B. Wu
Intended status: Standards Track Huawei
Expires: February 25, 2019 R. Wilton
Cisco Systems
X. Ding
August 24, 2018
YANG Data Model for ARP
draft-ietf-rtgwg-arp-yang-model-01
Abstract
This document defines a YANG data model for the management of the
Address Resolution Protocol (ARP). It extends the basic ARP
functionality contained in the ietf-ip YANG data model, defined in
RFC 8344, to provide management of optional ARP features and
statistics.
The YANG data model in this document conforms to the Network
Management Datastore Architecture defined in 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 February 25, 2019.
Copyright Notice
Copyright (c) 2018 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
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 4
2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 4
3. Design of the Data Model . . . . . . . . . . . . . . . . . . 4
3.1. ARP dynamic learning . . . . . . . . . . . . . . . . . . 4
3.2. proxy ARP . . . . . . . . . . . . . . . . . . . . . . . . 5
3.3. gratuitous ARP . . . . . . . . . . . . . . . . . . . . . 5
3.4. ietf-arp Module . . . . . . . . . . . . . . . . . . . . . 5
4. ARP YANG Module . . . . . . . . . . . . . . . . . . . . . . . 6
5. Data Model Examples . . . . . . . . . . . . . . . . . . . . . 12
5.1. Static ARP Entries . . . . . . . . . . . . . . . . . . . 12
5.2. ARP Dynamic Learning . . . . . . . . . . . . . . . . . . 13
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
7. Security Considerations . . . . . . . . . . . . . . . . . . . 14
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
9.1. Normative References . . . . . . . . . . . . . . . . . . 15
9.2. Informative References . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
This document defines a YANG [RFC7950] data model for the Address
Resolution Protocol [RFC0826] implementation and identification of
some common properties within a device. Devices have common
properties that need to be configured and monitored in a standard
way. This document is intended to present universal ARP protocol
configuration and many vendors can implement it.
The data model convers configuration of system parameters of ARP,
such as static ARP entries, timeout for dynamic ARP entries,
interface ARP, proxy ARP, and so on. It also provides information
about running state of ARP implementations.
The YANG modules in this document conform to the Network Management
Datastore Architecture (NMDA) [RFC8342].
Editorial Note: (To be removed by RFC Editor)
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This draft contains many placeholder values that need to be replaced
with finalized values at the time of publication. Please apply the
following replacements
o "XXXX" --> the assigned RFC value for this draft both in this
draft and in the YANG models under the revision statement.
o Revision date in model, in the format 2018-08-01 needs to get
updated with the date the draft gets approved. The date also
needs to get reflected on the line with <CODE BEGINS>.
1.1. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[BCP 14] [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The following terms are defined in [RFC8342] and are not redefined
here:
o client
o server
o configuration data
o system state
o state data
o intended configuration
o running configuration datastore
o operational state datastore
The following terms are defined in [RFC7950] and are not redefined
here:
o augment
o data model
o data node
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The terminology for describing YANG data models is found in
[RFC7950].
1.2. Tree Diagrams
Tree diagrams used in this document follow the notation defined in
[RFC8340]
2. Problem Statement
This document defines a YANG [RFC7950] configuration data model that
may be used to configure the ARP feature running on a system. Data
model "ietf-ip" [RFC8344] covers the address mapping functionality.
However, this functionality is strictly dependent on IPv4 networks,
and many ARP related functionalities are missing, e.g. device global
ARP entries and control, configuration related to dynamic ARP
learning, proxy ARP, gratuitous ARP, etc.
The data model makes use of the YANG "feature" construct which allows
implementations to support only those ARP features that lie within
their capabilities. It is intended this model be used by service
providers who manipulate devices from different vendors in a standard
way.
This model can be used to configure the ARP applications for
discovering the link layer address associated with a given Internet
layer address.
3. Design of the Data Model
This data model intends to describe the processing that a protocol
finds the hardware address, also known as Media Access Control (MAC)
address, of a host from its known IP address. These tasks include,
but are not limited to, adding a static entry in the ARP cache,
configuring dynamic ARP learning, proxy ARP, gratuitous ARP. There
are two kind of ARP configurations: global ARP configuration, which
is across all interfaces on the device, and per interface ARP
configuration.
3.1. ARP dynamic learning
ARP caching is the method of storing network addresses and the
associated data-link addresses in memory for a period of time as the
addresses are learned. This minimizes the use of valuable network
resources to broadcast for the same address each time a datagram is
sent.
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There are static ARP cache entries and dynamic ARP cache entries.
Static entries are manually configured and kept in the cache table on
a permanent basis. Dynamic entries are added by vendor software,
kept for a period of time, and then removed. We can specify how long
an entry remains in the ARP cache. If we specify a timeout of 0
seconds, entries are never cleared from the ARP cache.
3.2. proxy ARP
Proxy ARP [RFC1027] can be configured to enable the switch to respond
to ARP queries for network addresses by offering its own Ethernet
media access control (MAC) address. With proxy ARP enabled, the
switch captures and routes traffic to the intended destination.
3.3. gratuitous ARP
Gratuitous ARP requests help detect duplicate IP addresses. A
gratuitous ARP is a broadcast request for a router's own IP address.
If a router or switch sends an ARP request for its own IP address and
no ARP replies are received, the router- or switch-assigned IP
address is not being used by other nodes. However, if a router or
switch sends an ARP request for its own IP address and an ARP reply
is received, the router- or switch-assigned IP address is already
being used by another node.
3.4. ietf-arp Module
This module has one top level container, ARP, which consists of two
second level containers, which are used for static entries
configuration and global parameters control.
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module: ietf-arp
+--rw arp
+--rw dynamic-learning? boolean
+--rw proxy-arp? boolean
+--rw global-static-entries {global-static-entries}?
+--rw static-entry* [ip-address]
+--rw ip-address inet:ipv4-address-no-zone
+--rw mac-address yang:mac-address
augment /if:interfaces/if:interface:
+--rw arp
+--rw expiry-time? uint32
+--rw learn-disable? boolean
+--rw proxy
| +--rw mode? enumeration
+--rw probe
| +--rw interval? uint8
| +--rw times? uint8
| +--rw unicast? boolean
+--rw gratuitous
| +--rw enable? boolean
| +--rw interval? uint32
| +--rw drop? boolean
+--ro statistics
+--ro in-requests-pkts? yang:counter32
+--ro in-replies-pkts? yang:counter32
+--ro in-gratuitous-pkts? yang:counter32
+--ro out-requests-pkts? yang:counter32
+--ro out-replies-pkts? yang:counter32
+--ro out-gratuitous-pkts? yang:counter32
augment /if:interfaces/if:interface/ip:ipv4/ip:neighbor:
+--ro remaining-expiry-time? uint32
4. ARP YANG Module
This section presents the ARP YANG module defined in this document.
This module imports definitions from Common YANG Data Types
[RFC6991], A YANG Data Model for Interface Management [RFC8343], and
A YANG Data Model for IP Management [RFC8344].
<CODE BEGINS>file "ietf-arp@2018-08-01.yang"
module ietf-arp {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-arp";
prefix arp;
import ietf-inet-types {
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prefix inet;
reference "RFC 6991: Common YANG Data Types";
}
import ietf-yang-types {
prefix yang;
reference "RFC 6991: Common YANG Data Types";
}
import ietf-interfaces {
prefix if;
reference "RFC 8343: A Yang Data Model for Interface Management";
}
import ietf-ip {
prefix ip;
reference "RFC 8344: A Yang Data Model for IP Management";
}
organization
"IETF Routing Area Working Group (rtgwg)";
contact
"WG Web: <http://tools.ietf.org/wg/rtgwg/>
WG List: <mailto: rtgwg@ietf.org>
Editor: Xiaojian Ding
wjswsl@163.com
Editor: Feng Zheng
habby.zheng@huawei.com
Editor: Robert Wilton
rwilton@cisco.com";
description
"Address Resolution Protocol (ARP) management, which includes
static ARP configuration, dynamic ARP learning, ARP entry query,
and packet statistics collection.
Copyright (c) 2016 IETF Trust and the persons identified as
authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents
(http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see the RFC
itself for full legal notices.";
revision 2018-08-01 {
description
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"Init revision";
reference "RFC XXXX: A Yang Data Model for ARP";
}
feature global-static-entries {
description
"This feature indicates that the device allows static entries
to be configured globally.";
}
container arp {
description
"Address Resolution Protocol (ARP) management, which includes
static ARP configuration, dynamic ARP learning, ARP entry
query, and packet statistics collection.";
leaf dynamic-learning {
type boolean;
default "true";
description
"Controls the default dynamic ARP learning behavior on all
interfaces on the device:
true - dynamic learning is enabled on all interfaces by
default,
false - dynamic learning is disabled on all interfaces by
default";
}
leaf proxy-arp {
type boolean;
default "true";
description
"Controls the default proxy ARP behavior on all interfaces
on the device:
true - proxy ARP is enabled on interfaces by default,
false - proxy APR is disabled on interfaces by default";
}
container global-static-entries {
if-feature "global-static-entries";
description
"Set a global static ARP entry, which is independent of the
interface.";
list static-entry {
key "ip-address";
description
"List of ARP static entries that can be configured
globally.";
leaf ip-address {
type inet:ipv4-address-no-zone;
description
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"IP address, in dotted decimal notation.";
}
leaf mac-address {
type yang:mac-address;
mandatory true;
description
"MAC address in the format of H-H-H, in which H is a
hexadecimal number of 1 to 4 bits.";
}
}
}
}
augment "/if:interfaces/if:interface" {
description
"Augment interfaces with ARP configuration and state.";
container arp {
description
"Dynamic ARP related configuration and state";
leaf expiry-time {
type uint32 {
range "60..86400";
}
units "seconds";
description
"Aging time of a dynamic ARP entry.";
}
leaf learn-disable {
type boolean;
default "false";
description
"Whether dynamic ARP learning is disabled on an interface:
If the value is True, dynamic ARP learning is disabled.
If the value is False, dynamic ARP learning is enabled.";
}
container proxy {
description
"Configuration parameters for proxy ARP";
leaf mode {
type enumeration {
enum DISABLE {
description
"The system should not respond to ARP requests that
do not specify an IP address configured on the local
subinterface as the target address.";
}
enum REMOTE_ONLY {
description
"The system responds to ARP requests only when the
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sender and target IP addresses are in different
subnets.";
}
enum ALL {
description
"The system responds to ARP requests where the sender
and target IP addresses are in different subnets, as
well as those where they are in the same subnet.";
}
}
default "DISABLE";
description
"When set to a value other than DISABLE, the local system
should respond to ARP requests that are for target
addresses other than those that are configured on the
local subinterface using its own MAC address as the
target hardware address. If the REMOTE_ONLY value is
specified, replies are only sent when the target address
falls outside the locally configured subnets on the
interface, whereas with the ALL value, all requests,
regardless of their target address are replied to.";
reference
"RFC1027: Using ARP to Implement Transparent Subnet
Gateways";
}
}
container probe {
description
"Common configuration parameters for all ARP probe.";
leaf interval {
type uint8 {
range "1..5";
}
units "second";
description
"Interval for detecting dynamic ARP entries.";
}
leaf times {
type uint8 {
range "0..10";
}
description
"Number of aging probe attempts for a dynamic ARP entry.
If a device does not receive an ARP reply message after
the number of aging probe attempts reaches a specified
number,thedynamic ARP entry is deleted.";
}
leaf unicast {
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type boolean;
default "false";
description
"Send unicast ARP aging probe messages for a dynamic ARP
entry.";
}
}
container gratuitous-arp {
description
"Configure gratuitous ARP.";
leaf enable {
type boolean;
default "false";
description
"Enable or disable sending gratuitous ARP packet on
interface.";
}
leaf interval {
type uint32 {
range "1..86400";
}
units "second";
description
"The interval of sending gratuitous ARP packet on the
interface.";
}
leaf drop {
type boolean;
default "false";
description
"Drop the receipt of gratuitous ARP packets on the
interface.";
}
}
container statistics {
config false;
description
"IP ARP Statistics information on interfaces";
leaf in-requests-pkts {
type yang:counter32;
description
"Total ARP requests received";
}
leaf in-replies-pkts {
type yang:counter32;
description
"Total ARP replies received";
}
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leaf in-gratuitous-pkts {
type yang:counter32;
description
"Total gratuitous ARP received";
}
leaf out-requests-pkts {
type yang:counter32;
description
"Total ARP requests sent";
}
leaf out-replies-pkts {
type yang:counter32;
description
"Total ARP replies sent";
}
leaf out-gratuitous-pkts {
type yang:counter32;
description
"Total gratuitous ARP sent";
}
}
}
}
augment "/if:interfaces/if:interface/ip:ipv4/ip:neighbor" {
description
"Augment neighbor list with parameters of ARP, eg., support for
remaining expiry time query on interfaces.";
leaf remaining-expiry-time {
type uint32;
config false;
description
"Remaining expiry time of a dynamic ARP entry. ";
}
}
}
5. Data Model Examples
This section presents a simple but complete example of configuring
static ARP entries and dynamic learning, based on the YANG modules
specified in Section 4.
5.1. Static ARP Entries
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Requirement:
Enable static ARP entry global configuration (not rely on interface).
<config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
<arp xmlns="urn:ietf:params:xml:ns:yang:ietf-arp">
<static-tables>
<ip-address> 10.2.2.3 </ip-address>
<mac-address> 00e0-fc01-0000 </mac-address>
</static-tables>
</arp>
Requirement:
Enable static ARP entry configuration on interface (defined in
draft [I-D.ietf-netmod-rfc7277bis]).
<config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
<ipv4 xmlns="urn:ietf:params:xml:ns:yang:ietf-ip">
<neighbor>
<ip-address> 10.2.2.3 </ip-address>
<mac-address> 00e0-fc01-0000 </mac-address>
<if-name> GE1/0/1 </if-name>
</neighbor>
</ipv4>
5.2. ARP Dynamic Learning
Requirement:
Enable ARP dynamic learning configuration.
<config xmlns:xc="urn:ietf:params:xml:ns:netconf:base:1.0">
<arp xmlns="urn:ietf:params:xml:ns:yang:ietf-arp">
<if-name> GE1/0/1 </if-name>
<expire-time>1200</expire-time>
<learn-disable>false</learn-disable>
<proxy-enable>false</proxy-enable>
<probe>
<interval>5</interval>
<times>3</times>
<unicast>false</unicast>
</probe>
<gratuitous>
<gratuitous-enable>false<gratuitous-enable>
<interval>60</interval>
<drop>false</drop>
<gratuitous>
</arp>
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6. IANA Considerations
This document registers a URI in theIETF XML registry [RFC3688].
Following the format in [RFC3688], the following registration is
requested to be made:
URI: urn:ietf:params:xml:ns:yang:ietf-arp
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
This document registers a YANG module in the YANG Module Names
registry [RFC7950].
Name: ietf-arp
Namespace: urn:ietf:params:xml:ns:yang: ietf-arp
Prefix: arp
Reference: RFC XXXX
7. Security Considerations
The YANG module defined in this document is designed to be accessed
via YANG based management protocols, such as NETCONF [RFC6241] and
RESTCONF [RFC8040]. Both of these protocols have mandatory-to-
implement secure transport layers (e.g., SSH, TLS) with mutual
authentication.
The NETCONF access control model (NACM) [RFC8341] provides the means
to restrict access for particular users to a pre-configured subset of
all available protocol operations and content.
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:
arp/dynamic-learning: This leaf is used to enable ARP dynamic
learning on all interfaces.ARP dynamic learning could allow an
attacker to inject spoofed traffic into the network, e.g. denial-
of- service attack.
arp/proxy-arp and arp/proxy:These leaves are used to enable ARP
proxy on interface. They could allow traffic to be mis-configured
(denial-of- service attack).
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arp/global-static-entries/static-entry: This list specifies ARP
static entries configured on the device. By modifying this
information, an attacker can cause a node to either ignore
messages destined to it or accept messages it would otherwise
ignore.
/arp/gratuitous-arp:This leaf is used to enable sending gratuitous
ARP packet on an interface.This configuration could allow an
attacker to inject spoofed traffic into the network, e.g. man-in-
the-middle attack.
8. Acknowledgments
The authors wish to thank Alex Campbell and Reshad Rahman, Qin Wu,
Tom Petch, many others for their helpful comments.
9. References
9.1. Normative References
[RFC0826] Plummer, D., "An Ethernet Address Resolution Protocol: Or
Converting Network Protocol Addresses to 48.bit Ethernet
Address for Transmission on Ethernet Hardware", STD 37,
RFC 826, DOI 10.17487/RFC0826, November 1982,
<https://www.rfc-editor.org/info/rfc826>.
[RFC1027] Carl-Mitchell, S. and J. Quarterman, "Using ARP to
implement transparent subnet gateways", RFC 1027,
DOI 10.17487/RFC1027, October 1987,
<https://www.rfc-editor.org/info/rfc1027>.
[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>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/info/rfc6991>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>.
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[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[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>.
[RFC8343] Bjorklund, M., "A YANG Data Model for Interface
Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
<https://www.rfc-editor.org/info/rfc8343>.
[RFC8344] Bjorklund, M., "A YANG Data Model for IP Management",
RFC 8344, DOI 10.17487/RFC8344, March 2018,
<https://www.rfc-editor.org/info/rfc8344>.
9.2. Informative References
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>.
[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>.
Authors' Addresses
Feng Zheng
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: habby.zheng@huawei.com
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Bo Wu
Huawei
Email: lana.wubo@huawei.com
Robert Wilton
Cisco Systems
Email: rwilton@cisco.com
Xiaojian Ding
Email: wjswsl@163.com
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