Software-Defined Networking (SDN)-based IPsec Flow Protection
draft-ietf-i2nsf-sdn-ipsec-flow-protection-14
| Document | Type | Active Internet-Draft (i2nsf WG) | ||
|---|---|---|---|---|
| Authors | Rafael Marin-Lopez , Gabriel Lopez-Millan , Fernando Pereniguez-Garcia | |||
| Last updated | 2021-06-10 (latest revision 2021-03-25) | |||
| Replaces | draft-abad-i2nsf-sdn-ipsec-flow-protection | |||
| Stream | Internet Engineering Task Force (IETF) | |||
| Intended RFC status | Proposed Standard | |||
| Formats | plain text xml pdf htmlized bibtex | |||
| Yang Validation | ☯ 0 errors, 0 warnings. | |||
| Reviews | ||||
| Additional Resources | ||||
| Stream | WG state | Submitted to IESG for Publication | ||
| Document shepherd | Yoav Nir | |||
| Shepherd write-up | Show (last changed 2019-08-06) | |||
| IESG | IESG state | RFC Ed Queue | ||
| Action Holders |
(None)
|
|||
| Consensus Boilerplate | Yes | |||
| Telechat date | ||||
| Responsible AD | Roman Danyliw | |||
| Send notices to | Yoav Nir <ynir.ietf@gmail.com> | |||
| IANA | IANA review state | Version Changed - Review Needed | ||
| IANA action state | RFC-Ed-Ack | |||
| IANA expert review state | Expert Reviews OK | |||
| IANA expert review comments | In the XML examples, the "nc" namespace is defined but never used as far as I can tell. Which isn't an error or anything, just a bit surprising. Anyhow, looks good to me. | |||
| RFC Editor | RFC Editor state | AUTH48 | ||
| Details | ||||
I2NSF R. Marin-Lopez
Internet-Draft G. Lopez-Millan
Intended status: Standards Track University of Murcia
Expires: September 26, 2021 F. Pereniguez-Garcia
University Defense Center
March 25, 2021
Software-Defined Networking (SDN)-based IPsec Flow Protection
draft-ietf-i2nsf-sdn-ipsec-flow-protection-14
Abstract
This document describes how to provide IPsec-based flow protection
(integrity and confidentiality) by means of an Interface to Network
Security Function (I2NSF) controller. It considers two main well-
known scenarios in IPsec: (i) gateway-to-gateway and (ii) host-to-
host. The service described in this document allows the
configuration and monitoring of IPsec Security Associations (IPsec
SAs) from a I2NSF Controller to one or several flow-based Network
Security Functions (NSFs) that rely on IPsec to protect data traffic.
The document focuses on the I2NSF NSF-facing Interface by providing
YANG data models for configuring the IPsec databases, namely Security
Policy Database (SPD), Security Association Database (SAD), Peer
Authorization Database (PAD), and IKEv2. This allows IPsec SA
establishment with minimal intervention by the network administrator.
It defines three YANG modules but it does not define any new
protocol.
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 September 26, 2021.
Marin-Lopez, et al. Expires September 26, 2021 [Page 1]
Internet-Draft SDN-based IPsec Flow Protection March 2021
Copyright Notice
Copyright (c) 2021 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. 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 . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 5
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. SDN-based IPsec management description . . . . . . . . . . . 7
4.1. IKE case: IKEv2/IPsec in the NSF . . . . . . . . . . . . 7
4.2. IKE-less case: IPsec (no IKEv2) in the NSF. . . . . . . . 8
5. IKE case vs IKE-less case . . . . . . . . . . . . . . . . . . 10
5.1. Rekeying process . . . . . . . . . . . . . . . . . . . . 11
5.2. NSF state loss. . . . . . . . . . . . . . . . . . . . . . 11
5.3. NAT Traversal . . . . . . . . . . . . . . . . . . . . . . 12
5.4. NSF registration and discovery . . . . . . . . . . . . . 13
6. YANG configuration data models . . . . . . . . . . . . . . . 13
6.1. The 'ietf-i2nsf-ikec' Module . . . . . . . . . . . . . . 13
6.1.1. Data model overview . . . . . . . . . . . . . . . . . 14
6.1.2. YANG Module . . . . . . . . . . . . . . . . . . . . . 14
6.2. The 'ietf-i2nsf-ike' Module . . . . . . . . . . . . . . . 28
6.2.1. Data model overview . . . . . . . . . . . . . . . . . 29
6.2.2. Example Usage . . . . . . . . . . . . . . . . . . . . 33
6.2.3. YANG Module . . . . . . . . . . . . . . . . . . . . . 33
6.3. The 'ietf-i2nsf-ikeless' Module . . . . . . . . . . . . . 53
6.3.1. Data model overview . . . . . . . . . . . . . . . . . 53
6.3.2. Example Usage . . . . . . . . . . . . . . . . . . . . 57
6.3.3. YANG Module . . . . . . . . . . . . . . . . . . . . . 58
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 70
8. Security Considerations . . . . . . . . . . . . . . . . . . . 71
8.1. IKE case . . . . . . . . . . . . . . . . . . . . . . . . 72
8.2. IKE-less case . . . . . . . . . . . . . . . . . . . . . . 72
8.3. YANG modules . . . . . . . . . . . . . . . . . . . . . . 73
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 74
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 75
10.1. Normative References . . . . . . . . . . . . . . . . . . 75
Marin-Lopez, et al. Expires September 26, 2021 [Page 2]
Internet-Draft SDN-based IPsec Flow Protection March 2021
10.2. Informative References . . . . . . . . . . . . . . . . . 79
Appendix A. XML configuration example for IKE case (gateway-to-
gateway) . . . . . . . . . . . . . . . . . . . . . . 81
Appendix B. XML configuration example for IKE-less case (host-
to-host) . . . . . . . . . . . . . . . . . . . . . . 84
Appendix C. XML notification examples . . . . . . . . . . . . . 88
Appendix D. Operational use cases examples . . . . . . . . . . . 89
D.1. Example of IPsec SA establishment . . . . . . . . . . . . 89
D.1.1. IKE case . . . . . . . . . . . . . . . . . . . . . . 90
D.1.2. IKE-less case . . . . . . . . . . . . . . . . . . . . 91
D.2. Example of the rekeying process in IKE-less case . . . . 93
D.3. Example of managing NSF state loss in IKE-less case . . . 94
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 94
1. Introduction
Software-Defined Networking (SDN) is an architecture that enables
administrators to directly program, orchestrate, control and manage
network resources through software. The SDN paradigm relocates the
control of network resources to a centralized entity, namely the SDN
Controller. SDN controllers configure and manage distributed network
resources and provide an abstracted view of the network resources to
SDN applications. SDN applications can customize and automate the
operations (including management) of the abstracted network resources
in a programmable manner via this interface [RFC7149] [ITU-T.Y.3300]
[ONF-SDN-Architecture] [ONF-OpenFlow].
Recently, several network scenarios now demand a centralized way of
managing different security aspects, for example, Software-Defined
WANs (SD-WANs). SD-WANs are an SDN extension providing a software
abstraction to create secure network overlays over traditional WAN
and branch networks. SD-WANs utilize IPsec [RFC4301] as an
underlying security protocol. The goal of SD-WANs is to provide
flexible and automated deployment from a centralized point to enable
on-demand network security services such as IPsec Security
Association (IPsec SA) management. Additionally, Section 4.3.3 in
[RFC8192] describes another example use case for Cloud Data Center
Scenario titled "Client-Specific Security Policy in Cloud VPNs". The
use case in RFC 8192 states that "dynamic key management is critical
for securing the VPN and the distribution of policies". These VPNs
can be established using IPsec. The management of IPsec SAs in data
centers using a centralized entity is a scenario where the current
specification may be applicable.
Therefore, with the growth of SDN-based scenarios where network
resources are deployed in an autonomous manner, a mechanism to manage
IPsec SAs from a centralized entity becomes more relevant in the
industry.
Marin-Lopez, et al. Expires September 26, 2021 [Page 3]
Internet-Draft SDN-based IPsec Flow Protection March 2021
In response to this need, the Interface to Network Security Functions
(I2NSF) charter states that the goal of this working group is "to
define set of software interfaces and YANG data models for
controlling and monitoring aspects of physical and virtual Network
Security Functions". As defined in [RFC8192] an Network Security
Function (NSF) is "a function that is used to ensure integrity,
confidentiality, or availability of network communication; to detect
unwanted network activity; or to block, or at least mitigate, the
effects of unwanted activity". This document pays special attention
to flow-based NSFs that ensure integrity and confidentiality by means
of IPsec.
In fact, as Section 3.1.9 in [RFC8192] states "there is a need for a
controller to create, manage, and distribute various keys to
distributed NSFs.", however "there is a lack of a standard interface
to provision and manage security associations". Inspired by the SDN
paradigm, the I2NSF framework [RFC8329] defines a centralized entity,
the I2NSF Controller, which manages one or multiple NSFs through a
I2NSF NSF-Facing Interface. In this document an architecture is
defined for allowing the I2NSF Controller to carry out the key
management procedures. More specifically, three YANG data models are
defined for the I2NSF NSF-Facing Interface that allow the I2NSF
Controller to configure and monitor IPsec-enabled flow-based NSFs.
The IPsec architecture [RFC4301] defines a clear separation between
the processing to provide security services to IP packets and the key
management procedures to establish the IPsec SAs, which allows
centralizing the key management procedures in the I2NSF Controller.
This document considers two typical scenarios to autonomously manage
IPsec SAs: gateway-to-gateway and host-to-host [RFC6071]. In these
cases, hosts, gateways or both may act as NSFs. Due to its
complexity, consideration for the host-to-gateway scenario is out of
scope. The source of this complexity comes from the fact that, in
this scenario, the host may not be under the control of the I2NSF
controller and, therefore, it is not configurable. Nevertheless, the
I2NSF interfaces defined in this document can be considered as a
starting point to analyze and provide a solution for the host-to-
gateway scenario.
For the definition of the YANG data models for I2NSF NSF-Facing
Interface, this document considers two general cases, namely:
1) IKE case. The NSF implements the Internet Key Exchange version 2
(IKEv2) protocol and the IPsec databases: the Security Policy
Database (SPD), the Security Association Database (SAD) and the
Peer Authorization Database (PAD). The I2NSF Controller is in
charge of provisioning the NSF with the required information in
Marin-Lopez, et al. Expires September 26, 2021 [Page 4]
Internet-Draft SDN-based IPsec Flow Protection March 2021
the SPD and PAD (e.g., IKE credentials), and for the IKE protocol
itself (e.g., parameters for the IKE_SA_INIT negotiation).
2) IKE-less case. The NSF only implements the IPsec databases (no
IKE implementation). The I2NSF Controller will provide the
required parameters to create valid entries in the SPD and the
SAD of the NSF. Therefore, the NSF will only have support for
IPsec while key management functionality is moved to the I2NSF
Controller.
In both cases, a YANG data model for the I2NSF NSF-Facing Interface
is required to carry out this provisioning in a secure manner between
the I2NSF Controller and the NSF. Using YANG data modelling language
version 1.1 [RFC7950] and based on YANG data models defined in
[netconf-vpn], [I-D.tran-ipsecme-yang], an the data structures
defined in RFC 4301 [RFC4301] and RFC 7296 [RFC7296], this document
defines the required interfaces with a YANG data model for
configuration and state data for IKE, PAD, SPD and SAD (see
Section 6.1, Section 6.2 and Section 6.3). The proposed YANG data
model conforms to the Network Management Datastore Architecture
(NMDA) defined in [RFC8342]. Examples of the usage of these data
models can be found in Appendix A, Appendix B and Appendix C.
In summary, the objectives of this document are:
o To describe the architecture for I2NSF-based IPsec management,
which allows the establishment and management of IPsec security
associations from the I2NSF Controller in order to protect
specific data flows between two flow-based NSFs implementing
IPsec.
o To map this architecture to the I2NSF Framework.
o To define the interfaces required to manage and monitor the IPsec
SAs in the NSF from a I2NSF Controller. YANG data models are
defined for configuration and state data for IPsec and IKEv2
management through the I2NSF NSF-Facing Interface. The YANG
models can be used via existing protocols such as NETCONF
[RFC6241] or RESTCONF [RFC8040]. Thus, this document defines
three YANG modules (see Section 6) but does not define any new
protocol.
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
Marin-Lopez, et al. Expires September 26, 2021 [Page 5]
Internet-Draft SDN-based IPsec Flow Protection March 2021
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Terminology
This document uses the terminology described in [RFC8329], [RFC8192],
[RFC4301],[RFC7296], [RFC6241], [ITU-T.Y.3300]. The following term
is defined in [ITU-T.Y.3300]:
o Software-Defined Networking.
The following terms are defined in [RFC8192]:
o NSF.
o Flow-based NSF.
The following terms are defined in [RFC4301]:
o Peer Authorization Database (PAD).
o Security Associations Database (SAD).
o Security Policy Database (SPD).
The following two terms that are related or have identical
definition/usage in [RFC6437]:
o Flow or traffic flow.
The following term is defined in [RFC7296]:
o Internet Key Exchange version 2 (IKEv2).
The following terms are defined in [RFC6241]:
o Configuration data.
o Configuration datastore.
o State data.
o Startup configuration datastore.
o Running configuration datastore.
Marin-Lopez, et al. Expires September 26, 2021 [Page 6]
Internet-Draft SDN-based IPsec Flow Protection March 2021
4. SDN-based IPsec management description
As mentioned in Section 1, two cases are considered, depending on
whether the NSF implements IKEv2 or not: the IKE case and the IKE-
less case.
4.1. IKE case: IKEv2/IPsec in the NSF
In this case, the NSF implements IPsec with IKEv2 support. The I2NSF
Controller is in charge of managing and applying IPsec connection
information (determining which nodes need to start an IKEv2/IPsec
session, identifying the type of traffic to be protected, deriving
and delivering IKEv2 credentials such as a pre-shared key,
certificates, etc.), and applying other IKEv2 configuration
parameters (e.g., cryptographic algorithms for establishing an IKEv2
SA) to the NSF necessary for the IKEv2 negotiation.
With these entries, the IKEv2 implementation can operate to establish
the IPsec SAs. The I2NSF User establishes the IPsec requirements and
information about the end points (through the I2NSF Consumer-Facing
Interface, [RFC8329]), and the I2NSF Controller translates these
requirements into IKEv2, SPD and PAD entries that will be installed
into the NSF (through the I2NSF NSF-Facing Interface). With that
information, the NSF can just run IKEv2 to establish the required
IPsec SA (when the traffic flow needs protection). Figure 1 shows
the different layers and corresponding functionality.
Marin-Lopez, et al. Expires September 26, 2021 [Page 7]
Internet-Draft SDN-based IPsec Flow Protection March 2021
+-------------------------------------------+
| IPsec Management System | I2NSF User
+-------------------------------------------+
|
| I2NSF Consumer-Facing
| Interface
+-------------------------------------------+
| IKEv2 Configuration, PAD and SPD Entries | I2NSF
| Distribution | Controller
+-------------------------------------------+
|
| I2NSF NSF-Facing
| Interface
+-------------------------------------------+
| IKEv2 | IPsec(PAD, SPD) | Network
|-------------------------------------------| Security
| IPsec Data Protection and Forwarding | Function
+-------------------------------------------+
Figure 1: IKE case: IKE/IPsec in the NSF
I2NSF-based IPsec flow protection services provide dynamic and
flexible management of IPsec SAs in flow-based NSFs. In order to
support this capability in the IKE case, a YANG data model for IKEv2,
SPD and PAD configuration data, and for IKEv2 state data needs to be
defined for the I2NSF NSF-Facing Interface (see Section 6).
4.2. IKE-less case: IPsec (no IKEv2) in the NSF.
In this case, the NSF does not deploy IKEv2 and, therefore, the I2NSF
Controller has to perform the IKEv2 security functions and management
of IPsec SAs by populating and managing the SPD and the SAD.
As shown in Figure 2, when an I2NSF User enforces flow-based
protection policies through the Consumer-Facing Interface, the I2NSF
Controller translates these requirements into SPD and SAD entries,
which are installed in the NSF. PAD entries are not required since
there is no IKEv2 in the NSF.
Marin-Lopez, et al. Expires September 26, 2021 [Page 8]
Internet-Draft SDN-based IPsec Flow Protection March 2021
+-----------------------------------------+
| IPsec Management System | I2NSF User
+-----------------------------------------+
|
| I2NSF Consumer-Facing Interface
|
+-----------------------------------------+
| SPD and SAD Entries | I2NSF
| Distribution | Controller
+-----------------------------------------+
|
| I2NSF NSF-Facing Interface
|
+-----------------------------------------+
| IPsec (SPD, SAD) | Network
|-----------------------------------------| Security
| IPsec Data Protection and Forwarding | Function
+-----------------------------------------+
Figure 2: IKE-less case: IPsec (no IKEv2) in the NSF
In order to support the IKE-less case, a YANG data model for SPD and
SAD configuration data and SAD state data MUST be defined for the
NSF-Facing Interface (see Section 6).
Specifically, the IKE-less case assumes that the I2NSF Controller has
to perform some security functions that IKEv2 typically does, namely
(non-exhaustive):
o IV generation.
o Prevent counter resets for the same key.
o Generation of pseudo-random cryptographic keys for the IPsec SAs.
o Generation of the IPsec SAs when required based on notifications
(i.e. sadb-acquire) from the NSF.
o Rekey of the IPsec SAs based on notifications from the NSF (i.e.
expire).
o NAT Traversal discovery and management.
Additionally to these functions, another set of tasks must be
performed by the I2NSF Controller (non-exhaustive list):
Marin-Lopez, et al. Expires September 26, 2021 [Page 9]
Internet-Draft SDN-based IPsec Flow Protection March 2021
o IPsec SA's SPI random generation.
o Cryptographic algorithm selection.
o Usage of extended sequence numbers.
o Establishment of proper traffic selectors.
5. IKE case vs IKE-less case
In principle, the IKE case is easier to deploy than the IKE-less case
because current flow-based NSFs (either hosts or gateways) have
access to IKEv2 implementations. While gateways typically deploy an
IKEv2/IPsec implementation, hosts can easily install it. As a
downside, the NSF needs more resources to use IKEv2 such as memory
for the IKEv2 implementation, and computation, since each IPsec
security association rekeying MAY involve a Diffie-Hellman exchange.
Alternatively, the IKE-less case benefits the deployment in resource-
constrained NSFs. Moreover, IKEv2 does not need to be performed in
gateway-to-gateway and host-to-host scenarios under the same I2NSF
Controller (see Appendix D.1). On the contrary, the complexity of
creating and managing IPsec SAs is shifted to the I2NSF Controller
since IKEv2 is not in the NSF. As a consequence, this may result in
a more complex implementation in the controller side in comparison
with IKE case. For example, the I2NSF Controller has to deal with
the latency existing in the path between the I2NSF Controller and the
NSF, in order to solve tasks such as rekey, or creation and
installation of new IPsec SAs. However, this is not specific to this
contribution but a general aspect in any SDN-based network. In
summary, this complexity may create some scalability and performance
issues when the number of NSFs is high.
Nevertheless, literature around SDN-based network management using a
centralized controller (like the I2NSF Controller) is aware of
scalability and performance issues and solutions have been already
provided and discussed (e.g., hierarchical controllers, having
multiple replicated controllers, dedicated high-speed management
networks, etc). In the context of I2SNF-based IPsec management, one
way to reduce the latency and alleviate some performance issues can
be the installation of the IPsec policies and IPsec SAs at the same
time (proactive mode, as described in Appendix D.1) instead of
waiting for notifications (e.g., a sadb-acquire notification received
from a NSF requiring a new IPsec SA) to proceed with the IPsec SA
installation (reactive mode). Another way to reduce the overhead and
the potential scalability and performance issues in the I2NSF
Controller is to apply the IKE case described in this document, since
the IPsec SAs are managed between NSFs without the involvement of the
Marin-Lopez, et al. Expires September 26, 2021 [Page 10]
Internet-Draft SDN-based IPsec Flow Protection March 2021
I2NSF Controller at all, except by the initial configuration (i.e.
IKEv2, PAD and SPD entries) provided by the I2NSF Controller. Other
solutions, such as Controller-IKE
[I-D.carrel-ipsecme-controller-ike], have proposed that NSFs provide
their DH public keys to the I2NSF Controller, so that the I2NSF
Controller distributes all public keys to all peers. All peers can
calculate a unique pairwise secret for each other peer and there is
no inter-NSF messages. A rekey mechanism is further described in
[I-D.carrel-ipsecme-controller-ike].
In terms of security, IKE case provides better security properties
than IKE-less case, as discussed in Section 8. The main reason is
that the NSFs generate the session keys and not the I2NSF Controller.
5.1. Rekeying process
Performing a rekey for IPsec SAs is an important operation during the
IPsec SAs management. With the YANG data models defined in this
document the I2NSF Controller can configure parameters of the rekey
process (IKE case) or conduct the rekey process (IKE-less case).
Indeed, depending on the case, the rekey process is different.
For the IKE case, the rekeying process is carried out by IKEv2,
following the information defined in the SPD and SAD (i.e. based on
the IPsec SA lifetime established by the I2NSF Controller using the
YANG data model defined in this document). Therefore, IPsec
connections will live unless something different is required by the
I2NSF User or the I2NSF Controller detects something wrong.
For the IKE-less case, the I2NSF Controller MUST take care of the
rekeying process. When the IPsec SA is going to expire (e.g., IPsec
SA soft lifetime), it MUST create a new IPsec SA and it MAY remove
the old one (e.g. when the lifetime of the old IPsec SA has not been
defined). This rekeying process starts when the I2NSF Controller
receives a sadb-expire notification or, on the I2NSF Controller's
initiative, based on lifetime state data obtained from the NSF. How
the I2NSF Controller implements an algorithm for the rekey process is
out of the scope of this document. Nevertheless, an example of how
this rekey could be performed is described in Appendix D.2.
5.2. NSF state loss.
If one of the NSF restarts, it will lose the IPsec state (affected
NSF). By default, the I2NSF Controller can assume that all the state
has been lost and therefore it will have to send IKEv2, SPD and PAD
information to the NSF in the IKE case, and SPD and SAD information
in the IKE-less case.
Marin-Lopez, et al. Expires September 26, 2021 [Page 11]
Internet-Draft SDN-based IPsec Flow Protection March 2021
In both cases, the I2NSF Controller is aware of the affected NSF
(e.g., the NETCONF/TCP connection is broken with the affected NSF,
the I2NSF Controller is receiving sadb-bad-spi notification from a
particular NSF, etc.). Moreover, the I2NSF Controller keeps a list
of NSFs that have IPsec SAs with the affected NSF. Therefore, it
knows the affected IPsec SAs.
In the IKE case, the I2NSF Controller may need to configure the
affected NSF with the new IKEv2, SPD and PAD information.
Alternatively, IKEv2 configuration MAY be made permanent between NSF
reboots without compromising security by means of the startup
configuration datastore in the NSF. This way, each time a NSF
reboots it will use that configuration for each rebooting. It would
imply avoiding contact with the I2NSF Controller. Finally, the I2NSF
Controller may also need to send new parameters (e.g., a new fresh
PSK for authentication) to the NSFs which had IKEv2 SAs and IPsec SAs
with the affected NSF.
In the IKE-less case, the I2NSF Controller SHOULD delete the old
IPsec SAs in the non-failed nodes established with the affected NSF.
Once the affected node restarts, the I2NSF Controller MUST take the
necessary actions to reestablish IPsec protected communication
between the failed node and those others having IPsec SAs with the
affected NSF. How the I2NSF Controller implements an algorithm for
managing a potential NSF state loss is out of the scope of this
document. Nevertheless, an example of how this could be performed is
described in Appendix D.3.
5.3. NAT Traversal
In the IKE case, IKEv2 already provides a mechanism to detect whether
some of the peers or both are located behind a NAT. In this case,
UDP or TCP encapsulation for ESP packets ([RFC3948], [RFC8229]) is
required. Note that IPsec transport mode MUST NOT be used in this
specification when NAT is required.
In the IKE-less case, the NSF does not have the assistance of the
IKEv2 implementation to detect if it is located behind a NAT. If the
NSF does not have any other mechanism to detect this situation, the
I2NSF Controller SHOULD implement a mechanism to detect that case.
The SDN paradigm generally assumes the I2NSF Controller has a view of
the network under its control. This view is built either by
requesting information from the NSFs under its control, or by
information pushed from the NSFs to the I2NSF Controller. Based on
this information, the I2NSF Controller MAY guess if there is a NAT
configured between two hosts, and apply the required policies to both
NSFs besides activating the usage of UDP or TCP encapsulation of ESP
Marin-Lopez, et al. Expires September 26, 2021 [Page 12]
Internet-Draft SDN-based IPsec Flow Protection March 2021
packets ([RFC3948], [RFC8229]). The interface for discovering if the
NSF is behind a NAT is out of scope of this document.
If the I2NSF Controller does not have any mechanism to know whether a
host is behind a NAT or not, then the IKE-case MUST be used and not
the IKE-less case.
5.4. NSF registration and discovery
NSF registration refers to the process of providing the I2NSF
Controller information about a valid NSF such as certificate, IP
address, etc. This information is incorporated in a list of NSFs
under its control.
The assumption in this document is that, for both cases, before a NSF
can operate in this system, it MUST be registered in the I2NSF
Controller. In this way, when the NSF starts and establishes a
connection to the I2NSF Controller, it knows that the NSF is valid
for joining the system.
Either during this registration process or when the NSF connects with
the I2NSF Controller, the I2NSF Controller MUST discover certain
capabilities of this NSF, such as what are the cryptographic suites
supported, authentication method, the support of the IKE case and/or
the IKE-less case, etc.
The registration and discovery processes are out of the scope of this
document.
6. YANG configuration data models
In order to support the IKE and IKE-less cases, models are provided
for the different parameters and values that must be configured to
manage IPsec SAs. Specifically, the IKE case requires modeling IKEv2
configuration parameters, SPD and PAD, while the IKE-less case
requires configuration YANG data models for the SPD and SAD. Three
modules have been defined: ietf-i2nsf-ikec (Section 6.1, common to
both cases), ietf-i2nsf-ike (Section 6.2, IKE case), ietf-i2nsf-
ikeless (Section 6.3, IKE-less case). Since the module ietf-i2nsf-
ikec has only typedef and groupings common to the other modules, a
simplified view of the ietf-i2nsf-ike and ietf-i2nsf-ikeless modules
is shown.
6.1. The 'ietf-i2nsf-ikec' Module
Marin-Lopez, et al. Expires September 26, 2021 [Page 13]
Internet-Draft SDN-based IPsec Flow Protection March 2021
6.1.1. Data model overview
The module ietf-i2nsf-ikec has only definition of data types
(typedef) and groupings which are common to the other modules.
6.1.2. YANG Module
This module has normative references to [RFC3947], [RFC4301],
[RFC4303], [RFC8174], [RFC8221], [RFC3948], [RFC8229],
[IANA-Protocols-Number], [IKEv2-Parameters], [IKEv2-Transform-Type-1]
and [IKEv2-Transform-Type-3].
<CODE BEGINS> file "ietf-i2nsf-ikec@2021-03-18.yang"
module ietf-i2nsf-ikec {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikec";
prefix "nsfikec";
import ietf-inet-types {
prefix inet;
reference "RFC 6991: Common YANG Data Types";
}
organization "IETF I2NSF Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/i2nsf/>
WG List: <mailto:i2nsf@ietf.org>
Author: Rafael Marin-Lopez
<mailto:rafa@um.es>
Author: Gabriel Lopez-Millan
<mailto:gabilm@um.es>
Author: Fernando Pereniguez-Garcia
<mailto:fernando.pereniguez@cud.upct.es>
";
description
"Common Data model for the IKE and IKE-less cases
defined by the SDN-based IPsec flow protection service.
Copyright (c) 2020 IETF Trust and the persons
identified as authors of the code. All rights reserved.
Marin-Lopez, et al. Expires September 26, 2021 [Page 14]
Internet-Draft SDN-based IPsec Flow Protection March 2021
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
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX;;
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 "2021-03-18" {
description "Initial version.";
reference "RFC XXXX: Software-Defined Networking
(SDN)-based IPsec Flow Protection.";
}
typedef encr-alg-t {
type uint16;
description
"The encryption algorithm is specified with a 16-bit
number extracted from the IANA Registry. The acceptable
values MUST follow the requirement levels for
encryption algorithms for ESP and IKEv2.";
reference
"IANA; Internet Key Exchange V2 (IKEv2) Parameters;
Transform Atribute Types; Transform Type 1 - Encryption
Algorithm Transform IDs. RFC 8221 - Cryptographic
Algorithm Implementation Requirements and Usage
Guidance for Encapsulating Security Payload (ESP)
and Authentication Header (AH) and RFC 8247 -
Algorithm Implementation Requirements and Usage
Guidance for the Internet Key Exchange Protocol
Version 2 (IKEv2).";
}
typedef intr-alg-t {
type uint16;
description
"The integrity algorithm is specified with a 16-bit
number extracted from the IANA Registry.
The acceptable values MUST follow the requirement
Marin-Lopez, et al. Expires September 26, 2021 [Page 15]
Internet-Draft SDN-based IPsec Flow Protection March 2021
levels for integrity algorithms for ESP and IKEv2.";
reference
"IANA; Internet Key Exchange V2 (IKEv2) Parameters;
Transform Atribute Types; Transform Type 3 - Integrity
Algorithm Transform IDs. RFC 8221 - Cryptographic
Algorithm Implementation Requirements and Usage
Guidance for Encapsulating Security Payload (ESP)
and Authentication Header (AH) and RFC 8247 -
Algorithm Implementation Requirements and Usage
Guidance for the Internet Key Exchange Protocol
Version 2 (IKEv2).";
}
typedef ipsec-mode {
type enumeration {
enum transport {
description
"IPsec transport mode. No Network Address
Translation (NAT) support.";
}
enum tunnel {
description "IPsec tunnel mode.";
}
}
description
"Type definition of IPsec mode: transport or
tunnel.";
reference
"Section 3.2 in RFC 4301.";
}
typedef esp-encap {
type enumeration {
enum espintcp {
description
"ESP in TCP encapsulation.";
reference
"RFC 8229 - TCP Encapsulation of IKE and
IPsec Packets.";
}
enum espinudp {
description
"ESP in UDP encapsulation.";
reference
"RFC 3948 - UDP Encapsulation of IPsec ESP
Packets.";
}
enum none {
Marin-Lopez, et al. Expires September 26, 2021 [Page 16]
Internet-Draft SDN-based IPsec Flow Protection March 2021
description
"No ESP encapsulation.";
}
}
description
"Types of ESP encapsulation when Network Address
Translation (NAT) may be present between two NSFs.";
reference
"RFC 8229 - TCP Encapsulation of IKE and IPsec
Packets and RFC 3948 - UDP Encapsulation of IPsec
ESP Packets.";
}
typedef ipsec-protocol-parameters {
type enumeration {
enum esp { description "IPsec ESP protocol."; }
}
description
"Only the Encapsulation Security Protocol (ESP) is
supported but it could be extended in the future.";
reference
"RFC 4303- IP Encapsulating Security Payload
(ESP).";
}
typedef lifetime-action {
type enumeration {
enum terminate-clear {
description
"Terminates the IPsec SA and allows the
packets through.";
}
enum terminate-hold {
description
"Terminates the IPsec SA and drops the
packets.";
}
enum replace {
description
"Replaces the IPsec SA with a new one:
rekey. ";
}
}
description
"When the lifetime of an IPsec SA expires an action
needs to be performed for the IPsec SA that
reached the lifetime. There are three posible
options: terminate-clear, terminate-hold and
Marin-Lopez, et al. Expires September 26, 2021 [Page 17]
Internet-Draft SDN-based IPsec Flow Protection March 2021
replace.";
reference
"Section 4.5 in RFC 4301.";
}
typedef ipsec-traffic-direction {
type enumeration {
enum inbound {
description "Inbound traffic.";
}
enum outbound {
description "Outbound traffic.";
}
}
description
"IPsec traffic direction is defined in
two directions: inbound and outbound.
From a NSF perspective, inbound and
outbound are defined as mentioned
in RFC 4301 (Section 3.1).";
reference
"Section 3.1 in RFC 4301.";
}
typedef ipsec-spd-action {
type enumeration {
enum protect {
description
"PROTECT the traffic with IPsec.";
}
enum bypass {
description
"BYPASS the traffic. The packet is forwarded
without IPsec protection.";
}
enum discard {
description
"DISCARD the traffic. The IP packet is
discarded.";
}
}
description
"The action when traffic matches an IPsec security
policy. According to RFC 4301 there are three
possible values: BYPASS, PROTECT AND DISCARD";
reference
"Section 4.4.1 in RFC 4301.";
}
Marin-Lopez, et al. Expires September 26, 2021 [Page 18]
Internet-Draft SDN-based IPsec Flow Protection March 2021
typedef ipsec-inner-protocol {
type union {
type uint8;
type enumeration {
enum any {
value 256;
description
"Any IP protocol number value.";
}
}
}
default any;
description
"IPsec protection can be applied to specific IP
traffic and layer 4 traffic (TCP, UDP, SCTP, etc.)
or ANY protocol in the IP packet payload. We
The IP protocol number is specified with an uint8
or ANY defining an enumerate with value 256 to
indicate the protocol number. NOTE: In case
of IPv6, the protocol in the IP packet payload
is indicated in the Next Header field of the IPv6
packet.";
reference
"Section 4.4.1.1 in RFC 4301.
IANA Registry - Protocol Numbers.";
}
grouping encap {
description
"This group of nodes allows to define the type of
encapsulation in case NAT traversal is
required and includes port information.";
leaf espencap {
type esp-encap;
default none;
description
"ESP in TCP, ESP in UDP or ESP in TLS.";
}
leaf sport {
type inet:port-number;
default 4500;
description
"Encapsulation source port.";
}
leaf dport {
type inet:port-number;
default 4500;
description
Marin-Lopez, et al. Expires September 26, 2021 [Page 19]
Internet-Draft SDN-based IPsec Flow Protection March 2021
"Encapsulation destination port.";
}
leaf-list oaddr {
type inet:ip-address;
description
"If required, this is the original address that
was used before NAT was applied over the Packet.
";
}
reference
"RFC 3947 and RFC 8229.";
}
grouping lifetime {
description
"Different lifetime values limited to an IPsec SA.";
leaf time {
type uint32;
units "seconds";
default 0;
description
"Time in seconds since the IPsec SA was added.
For example, if this value is 180 seconds it
means the IPsec SA expires in 180 seconds since
it was added. The value 0 implies infinite.";
}
leaf bytes {
type uint64;
default 0;
description
"If the IPsec SA processes the number of bytes
expressed in this leaf, the IPsec SA expires and
SHOULD be rekeyed. The value 0 implies
infinite.";
}
leaf packets {
type uint32;
default 0;
description
"If the IPsec SA processes the number of packets
expressed in this leaf, the IPsec SA expires and
SHOULD be rekeyed. The value 0 implies
infinite.";
}
leaf idle {
type uint32;
units "seconds";
Marin-Lopez, et al. Expires September 26, 2021 [Page 20]
Internet-Draft SDN-based IPsec Flow Protection March 2021
default 0;
description
"When a NSF stores an IPsec SA, it
consumes system resources. For an idle IPsec SA this
is a waste of resources. If the IPsec SA is idle
during this number of seconds the IPsec SA
SHOULD be removed. The value 0 implies
infinite.";
}
reference
"Section 4.4.2.1 in RFC 4301.";
}
grouping port-range {
description
"This grouping defines a port range, such as
expressed in RFC 4301. For example: 1500 (Start
Port Number)-1600 (End Port Number).
A port range is used in the Traffic Selector.";
leaf start {
type inet:port-number;
description "Start port number.";
}
leaf end {
type inet:port-number;
must '. >= ../start' {
error-message
"The end port number MUST be equal or greater
than the start port number.";
}
description
"End port number. To express a single port, set
the same value as start and end.";
}
reference "Section 4.4.1.2 in RFC 4301.";
}
grouping tunnel-grouping {
description
"The parameters required to define the IP tunnel
endpoints when IPsec SA requires tunnel mode. The
tunnel is defined by two endpoints: the local IP
address and the remote IP address.";
leaf local {
type inet:ip-address;
mandatory true;
Marin-Lopez, et al. Expires September 26, 2021 [Page 21]
Internet-Draft SDN-based IPsec Flow Protection March 2021
description
"Local IP address' tunnel endpoint.";
}
leaf remote {
type inet:ip-address;
mandatory true;
description
"Remote IP address' tunnel endpoint.";
}
leaf df-bit {
type enumeration {
enum clear {
description
"Disable the DF (Don't Fragment) bit
in the outer header. This is the
default value.";
}
enum set {
description
"Enable the DF bit in the outer header.";
}
enum copy {
description
"Copy the DF bit to the outer header.";
}
}
default clear;
description
"Allow configuring the DF bit when encapsulating
tunnel mode IPsec traffic. RFC 4301 describes
three options to handle the DF bit during
tunnel encapsulation: clear, set and copy from
the inner IP header. This MUST be ignored or
has no meaning when the local/remote
IP addresses are IPv6 addresses.";
reference
"Section 8.1 in RFC 4301.";
}
leaf bypass-dscp {
type boolean;
default true;
description
"If True to copy the DSCP value from inner header
to outer header. If False to map DSCP values
from an inner header to values in an outer header
following ../dscp-mapping";
reference
"Section 4.4.1.2. in RFC 4301.";
Marin-Lopez, et al. Expires September 26, 2021 [Page 22]
Internet-Draft SDN-based IPsec Flow Protection March 2021
}
list dscp-mapping {
must '../bypass-dscp = "false"';
key id;
ordered-by user;
leaf id {
type uint8;
description
"The index of list with the
different mappings.";
}
leaf inner-dscp {
type inet:dscp;
description
"The DSCP value of the inner IP packet. If this
leaf is not defined it means ANY inner DSCP value";
}
leaf outer-dscp {
type inet:dscp;
default 0;
description
"The DSCP value of the outer IP packet";
}
description
"A list that represents an array with the mapping from the
inner DSCP value to outer DSCP value when bypass-dscp is
False. To express a default mapping in the list where any
other inner dscp value is not matching a node in the list,
a new node has to be included at the end of the list where
the leaf inner-dscp is not defined (ANY) and the leaf
outer-dscp includes the value of the mapping. If there is no
value set in the leaf outer-dscp the default value for this
leaf is 0.";
reference
"Section 4.4.1.2. and Appendix C in RFC 4301.";
}
}
grouping selector-grouping {
description
"This grouping contains the definition of a Traffic
Selector, which is used in the IPsec policies and
IPsec SAs.";
leaf local-prefix {
type inet:ip-prefix;
Marin-Lopez, et al. Expires September 26, 2021 [Page 23]
Internet-Draft SDN-based IPsec Flow Protection March 2021
mandatory true;
description
"Local IP address prefix.";
}
leaf remote-prefix {
type inet:ip-prefix;
mandatory true;
description
"Remote IP address prefix.";
}
leaf inner-protocol {
type ipsec-inner-protocol;
default any;
description
"Inner Protocol that is going to be
protected with IPsec.";
}
list local-ports {
key "start end";
uses port-range;
description
"List of local ports. When the inner
protocol is ICMP this 16 bit value
represents code and type.
If this list is not defined
it is assumed that start and
end are 0 by default (any port).";
}
list remote-ports {
key "start end";
uses port-range;
description
"List of remote ports. When the upper layer
protocol is ICMP this 16 bit value represents
code and type.If this list is not defined
it is assumed that start and end are 0 by
default (any port)";
}
reference
"Section 4.4.1.2 in RFC 4301.";
}
grouping ipsec-policy-grouping {
description
"Holds configuration information for an IPsec SPD
entry.";
leaf anti-replay-window-size {
Marin-Lopez, et al. Expires September 26, 2021 [Page 24]
Internet-Draft SDN-based IPsec Flow Protection March 2021
type uint32;
default 64;
description
"To set the anti-replay window size.
The default value is set
to 64 following RFC 4303 recommendation.";
reference
"Section 3.4.3 in RFC 4303";
}
container traffic-selector {
description
"Packets are selected for
processing actions based on traffic selector
values, which refer to IP and inner protocol
header information.";
uses selector-grouping;
reference
"Section 4.4.4.1 in RFC 4301.";
}
container processing-info {
description
"SPD processing. If the required processing
action is protect, it contains the required
information to process the packet.";
leaf action {
type ipsec-spd-action;
default discard;
description
"If bypass or discard, container
ipsec-sa-cfg is empty.";
}
container ipsec-sa-cfg {
when "../action = 'protect'";
description
"IPsec SA configuration included in the SPD
entry.";
leaf pfp-flag {
type boolean;
default false;
description
"Each selector has a Populate From
Packet (PFP) flag. If asserted for a
given selector X, the flag indicates
that the IPsec SA to be created should
take its value (local IP address,
remote IP address, Next Layer
Protocol, etc.) for X from the value
in the packet. Otherwise, the IPsec SA
Marin-Lopez, et al. Expires September 26, 2021 [Page 25]
Internet-Draft SDN-based IPsec Flow Protection March 2021
should take its value(s) for X from
the value(s) in the SPD entry.";
}
leaf ext-seq-num {
type boolean;
default false;
description
"True if this IPsec SA is using extended
sequence numbers. If true, the 64-bit
extended sequence number counter is used;
if false, the normal 32-bit sequence
number counter is used.";
}
leaf seq-overflow {
type boolean;
default false;
description
"The flag indicating whether
overflow of the sequence number
counter should prevent transmission
of additional packets on the IPsec
SA (false) and, therefore needs to
be rekeyed, or whether rollover is
permitted (true). If Authenticated
Encryption with Associated Data
(AEAD) is used (leaf
esp-algorithms/encryption/algorithm-type)
this flag MUST be false. Setting this
flag to true is strongly discouraged.";
}
leaf stateful-frag-check {
type boolean;
default false;
description
"Indicates whether (true) or not (false)
stateful fragment checking applies to
the IPsec SA to be created.";
}
leaf mode {
type ipsec-mode;
default transport;
description
"IPsec SA has to be processed in
transport or tunnel mode.";
}
leaf protocol-parameters {
type ipsec-protocol-parameters;
default esp;
Marin-Lopez, et al. Expires September 26, 2021 [Page 26]
Internet-Draft SDN-based IPsec Flow Protection March 2021
description
"Security protocol of the IPsec SA:
Only ESP is supported but it could be
extended in the future.";
}
container esp-algorithms {
when "../protocol-parameters = 'esp'";
description
"Configuration of Encapsulating
Security Payload (ESP) parameters and
algorithms.";
leaf-list integrity {
type intr-alg-t;
default 0;
ordered-by user;
description
"Configuration of ESP authentication
based on the specified integrity
algorithm. With AEAD encryption
algorithms, the integrity node is
not used.";
reference
"Section 3.2 in RFC 4303.";
}
list encryption {
key id;
ordered-by user;
leaf id {
type uint16;
description
"An identifier that unequivocally identifies each
entry of the list, i.e., an encryption algorithm
and its key-length (if required).";
}
leaf algorithm-type {
type encr-alg-t;
default 20;
description
"Default value 20 (ENCR_AES_GCM_16)";
}
leaf key-length {
type uint16;
default 128;
description
"By default key length is 128
bits";
}
Marin-Lopez, et al. Expires September 26, 2021 [Page 27]
Internet-Draft SDN-based IPsec Flow Protection March 2021
description
"Encryption or AEAD algorithm for the
IPsec SAs. This list is ordered
following from the higher priority to
lower priority. First node of the
list will be the algorithm with
higher priority. In case the list
is empty, then
no encryption algorithm
is applied (NULL).";
reference
"Section 3.2 in RFC 4303.";
}
leaf tfc-pad {
type boolean;
default false;
description
"If Traffic Flow Confidentiality
(TFC) padding for ESP encryption
can be used (true) or not (false)";
reference
"Section 2.7 in RFC 4303.";
}
reference
"RFC 4303.";
}
container tunnel {
when "../mode = 'tunnel'";
uses tunnel-grouping;
description
"IPsec tunnel endpoints definition.";
}
}
reference
"Section 4.4.1.2 in RFC 4301.";
}
}
}
<CODE ENDS>
6.2. The 'ietf-i2nsf-ike' Module
In this section, the YANG module for the IKE case is described.
Marin-Lopez, et al. Expires September 26, 2021 [Page 28]
Internet-Draft SDN-based IPsec Flow Protection March 2021
6.2.1. Data model overview
The model related to IKEv2 has been extracted from reading IKEv2
standard in [RFC7296], and observing some open source
implementations, such as Strongswan [strongswan] or Libreswan
[libreswan].
The definition of the PAD model has been extracted from the
specification in section 4.4.3 in [RFC4301] (NOTE: Many
implementations integrate PAD configuration as part of the IKEv2
configuration).
The definition of the SPD model has been mainly extracted from the
specification in section 4.4.1 and Appendix D in [RFC4301].
The YANG data model for the IKE case is defined by the module "ietf-
i2nsf-ike". Its structure is depicted in the following diagram,
using the notation syntax for YANG tree diagrams ([RFC8340]).
module: ietf-i2nsf-ike
+--rw ipsec-ike
+--rw pad
| +--rw pad-entry* [name]
| +--rw name string
| +--rw (identity)
| | +--:(ipv4-address)
| | | +--rw ipv4-address? inet:ipv4-address
| | +--:(ipv6-address)
| | | +--rw ipv6-address? inet:ipv6-address
| | +--:(fqdn-string)
| | | +--rw fqdn-string? inet:domain-name
| | +--:(rfc822-address-string)
| | | +--rw rfc822-address-string? string
| | +--:(dnx509)
| | | +--rw dnx509? binary
| | +--:(gnx509)
| | | +--rw gnx509? binary
| | +--:(id-key)
| | | +--rw id-key? binary
| | +--:(id-null)
| | +--rw id-null? empty
| +--rw auth-protocol? auth-protocol-type
| +--rw peer-authentication
| +--rw auth-method? auth-method-type
| +--rw eap-method
| | +--rw eap-type uint64
| +--rw pre-shared
Marin-Lopez, et al. Expires September 26, 2021 [Page 29]
Internet-Draft SDN-based IPsec Flow Protection March 2021
| | +--rw secret? yang:hex-string
| +--rw digital-signature
| +--rw ds-algorithm? uint8
| +--rw (public-key)?
| | +--:(raw-public-key)
| | | +--rw raw-public-key? binary
| | +--:(cert-data)
| | +--rw cert-data? binary
| +--rw private-key? binary
| +--rw ca-data* binary
| +--rw crl-data? binary
| +--rw crl-uri? inet:uri
| +--rw oscp-uri? inet:uri
+--rw conn-entry* [name]
| +--rw name string
| +--rw autostartup? autostartup-type
| +--rw initial-contact? boolean
| +--rw version? auth-protocol-type
| +--rw fragmentation
| | +--rw enable? boolean
| | +--rw mtu? uint16
| +--rw ike-sa-lifetime-soft
| | +--rw rekey-time? uint32
| | +--rw reauth-time? uint32
| +--rw ike-sa-lifetime-hard
| | +--rw over-time? uint32
| +--rw ike-sa-intr-alg* nsfikec:intr-alg-t
| +--rw ike-sa-encr-alg* [id]
| | +--rw id uint16
| | +--rw algorithm-type? nsfikec:encr-alg-t
| | +--rw key-length? uint16
| +--rw dh-group? fs-group
| +--rw half-open-ike-sa-timer? uint32
| +--rw half-open-ike-sa-cookie-threshold? uint32
| +--rw local
| | +--rw local-pad-entry-name string
| +--rw remote
| | +--rw remote-pad-entry-name string
| +--rw encapsulation-type
| | +--rw espencap? esp-encap
| | +--rw sport? inet:port-number
| | +--rw dport? inet:port-number
| | +--rw oaddr* inet:ip-address
| +--rw spd
| | +--rw spd-entry* [name]
| | +--rw name string
| | +--rw ipsec-policy-config
| | +--rw anti-replay-window-size? uint32
Marin-Lopez, et al. Expires September 26, 2021 [Page 30]
Internet-Draft SDN-based IPsec Flow Protection March 2021
| | +--rw traffic-selector
| | | +--rw local-prefix inet:ip-prefix
| | | +--rw remote-prefix inet:ip-prefix
| | | +--rw inner-protocol? ipsec-inner-protocol
| | | +--rw local-ports* [start end]
| | | | +--rw start inet:port-number
| | | | +--rw end inet:port-number
| | | +--rw remote-ports* [start end]
| | | +--rw start inet:port-number
| | | +--rw end inet:port-number
| | +--rw processing-info
| | +--rw action? ipsec-spd-action
| | +--rw ipsec-sa-cfg
| | +--rw pfp-flag? boolean
| | +--rw ext-seq-num? boolean
| | +--rw seq-overflow? boolean
| | +--rw stateful-frag-check? boolean
| | +--rw mode? ipsec-mode
| | +--rw protocol-parameters? ipsec-protocol-parameters
| | +--rw esp-algorithms
| | | +--rw integrity* intr-alg-t
| | | +--rw encryption* [id]
| | | | +--rw id uint16
| | | | +--rw algorithm-type? encr-alg-t
| | | | +--rw key-length? uint16
| | | +--rw tfc-pad? boolean
| | +--rw tunnel
| | +--rw local inet:ip-address
| | +--rw remote inet:ip-address
| | +--rw df-bit? enumeration
| | +--rw bypass-dscp? boolean
| | +--rw dscp-mapping* [id]
| | +--rw id uint8
| | +--rw inner-dscp? inet:dscp
| | +--rw outer-dscp? inet:dscp
| +--rw child-sa-info
| | +--rw fs-groups* fs-group
| | +--rw child-sa-lifetime-soft
| | | +--rw time? uint32
| | | +--rw bytes? yang:counter64
| | | +--rw packets? uint32
| | | +--rw idle? uint32
| | | +--rw action? nsfikec:lifetime-action
| | +--rw child-sa-lifetime-hard
| | +--rw time? uint32
| | +--rw bytes? yang:counter64
| | +--rw packets? uint32
| | +--rw idle? uint32
Marin-Lopez, et al. Expires September 26, 2021 [Page 31]
Internet-Draft SDN-based IPsec Flow Protection March 2021
| +--ro state
| +--ro initiator? boolean
| +--ro initiator-ikesa-spi? ike-spi
| +--ro responder-ikesa-spi? ike-spi
| +--ro nat-local? boolean
| +--ro nat-remote? boolean
| +--ro encapsulation-type
| | +--ro espencap? esp-encap
| | +--ro sport? inet:port-number
| | +--ro dport? inet:port-number
| | +--ro oaddr* inet:ip-address
| +--ro established? uint64
| +--ro current-rekey-time? uint64
| +--ro current-reauth-time? uint64
+--ro number-ike-sas
+--ro total? yang:gauge64
+--ro half-open? yang:gauge64
+--ro half-open-cookies? yang:gauge64
The YANG data model consists of a unique "ipsec-ike" container
defined as follows. Firstly, it contains a "pad" container that
serves to configure the Peer Authentication Database with
authentication information about local and remote peers (NSFs). More
precisely, it consists of a list of entries, each one indicating the
identity, authentication method and credentials that a particular
peer (local or remote) will use. Therefore, each entry contains
identity, authentication information, and credentials of either the
local NSF or the remote NSF. As a consequence, the I2NF Controller
can store identity, authentication information and credentials for
the local NSF and the remote NSF.
Next, a list "conn-entry" is defined with information about the
different IKE connections a peer can maintain with others. Each
connection entry is composed of a wide number of parameters to
configure different aspects of a particular IKE connection between
two peers: local and remote peer authentication information; IKE SA
configuration (soft and hard lifetimes, cryptographic algorithms,
etc.); list of IPsec policies describing the type of network traffic
to be secured (local/remote subnet and ports, etc.) and how must be
protected (ESP, tunnel/transport, cryptographic algorithms, etc.);
CHILD SA configuration (soft and hard lifetimes); and, state
information of the IKE connection (SPIs, usage of NAT, current
expiration times, etc.).
Lastly, the "ipsec-ike" container declares a "number-ike-sas"
container to specify state information reported by the IKE software
related to the amount of IKE connections established.
Marin-Lopez, et al. Expires September 26, 2021 [Page 32]
Internet-Draft SDN-based IPsec Flow Protection March 2021
6.2.2. Example Usage
Appendix A shows an example of IKE case configuration for a NSF, in
tunnel mode (gateway-to-gateway), with NSFs authentication based on
X.509 certificates.
6.2.3. YANG Module
This YANG module has normative references to [RFC2247], [RFC5280],
[RFC4301], [RFC5280], [RFC5915], [RFC6991], [RFC7296], [RFC7383],
[RFC7427], [RFC7619], [RFC8017], [ITU-T.X.690], [RFC5322], [RFC8229],
[RFC8174], [IKEv2-Auth-Method], [IKEv2-Transform-Type-4],
[IKEv2-Parameters] and [IANA-Method-Type].
<CODE BEGINS> file "ietf-i2nsf-ike@2021-03-18.yang"
module ietf-i2nsf-ike {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-i2nsf-ike";
prefix "nsfike";
import ietf-inet-types {
prefix inet;
reference "RFC 6991: Common YANG Data Types";
}
import ietf-yang-types {
prefix yang;
reference "RFC 6991: Common YANG Data Types";
}
import ietf-i2nsf-ikec {
prefix nsfikec;
reference
"RFC XXXX: Software-Defined Networking
(SDN)-based IPsec Flow Protection.";
}
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Access Control
Model.";
}
organization "IETF I2NSF Working Group";
Marin-Lopez, et al. Expires September 26, 2021 [Page 33]
Internet-Draft SDN-based IPsec Flow Protection March 2021
contact
"WG Web: <https://datatracker.ietf.org/wg/i2nsf/>
WG List: <mailto:i2nsf@ietf.org>
Author: Rafael Marin-Lopez
<mailto:rafa@um.es>
Author: Gabriel Lopez-Millan
<mailto:gabilm@um.es>
Author: Fernando Pereniguez-Garcia
<mailto:fernando.pereniguez@cud.upct.es>
";
description
"This module contains IPsec IKE case model for the SDN-based
IPsec flow protection service.
Copyright (c) 2020 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.
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 "2021-03-18" {
description "Initial version.";
reference
"RFC XXXX: Software-Defined Networking
(SDN)-based IPsec Flow Protection.";
}
typedef ike-spi {
type uint64 { range "0..max"; }
Marin-Lopez, et al. Expires September 26, 2021 [Page 34]
Internet-Draft SDN-based IPsec Flow Protection March 2021
description
"Security Parameter Index (SPI)'s IKE SA.";
reference
"Section 2.6 in RFC 7296.";
}
typedef autostartup-type {
type enumeration {
enum add {
description
"IKE/IPsec configuration is only loaded into
IKE implementation but IKE/IPsec SA is not
started.";
}
enum on-demand {
description
"IKE/IPsec configuration is loaded
into IKE implementation. The IPsec policies
are transferred to the NSF but the
IPsec SAs are not established immediately.
The IKE implementation will negotiate the
IPsec SAs when they are required.
(i.e. through an ACQUIRE notification).";
}
enum start {
description
"IKE/IPsec configuration is loaded
and transferred to the NSF's kernel, and the
IKEv2 based IPsec SAs are established
immediately without waiting for any packet.";
}
}
description
"Different policies to set IPsec SA configuration
into NSF's kernel when IKEv2 implementation has
started.";
}
typedef fs-group {
type uint16;
description
"DH groups for IKE and IPsec SA rekey.";
reference
"IANA; Internet Key Exchange V2 (IKEv2) Parameters;
Transform Atribute Types; Transform Type 4 -
Diffie-Hellman Group Transform IDs.
Section 3.3.2 in RFC 7296.";
}
Marin-Lopez, et al. Expires September 26, 2021 [Page 35]
Internet-Draft SDN-based IPsec Flow Protection March 2021
typedef auth-protocol-type {
type enumeration {
enum ikev2 {
value 2;
description
"IKEv2 authentication protocol. It is the
only one defined right now. An enum is
used for further extensibility.";
}
}
description
"IKE authentication protocol version specified in the
Peer Authorization Database (PAD). It is defined as
enumerated to allow new IKE versions in the
future.";
reference
"RFC 7296.";
}
typedef auth-method-type {
type enumeration {
enum pre-shared {
description
"Select pre-shared key as the
authentication method.";
reference
"RFC 7296.";
}
enum eap {
description
"Select EAP as the authentication method.";
reference
"RFC 7296.";
}
enum digital-signature {
description
"Select digital signature as the authentication method.";
reference
"RFC 7296 and RFC 7427.";
}
enum null {
description
"Null authentication.";
reference
"RFC 7619.";
}
}
description
Marin-Lopez, et al. Expires September 26, 2021 [Page 36]
Internet-Draft SDN-based IPsec Flow Protection March 2021
"Peer authentication method specified in the Peer
Authorization Database (PAD).";
}
container ipsec-ike {
description
"IKE configuration for a NSF. It includes PAD
parameters, IKE connection information and state
data.";
container pad {
description
"Configuration of the Peer Authorization Database
(PAD). Each entry of PAD contains authentication
information of either the local peer or the remote peer.
Therefore, the I2NSF Controller stores authentication
information (and credentials) not only for the remote NSF
but also for the local NSF. The local NSF MAY use the
same identity for different types of authentication
and credentials. Pointing to the entry for a local NSF
(e.g., A) and the entry for remote NSF (e.g., B)
is possible to specify all the required information to
carry out the authentication between A and B (see
../conn-entry/local and ../conn-entry/remote).";
list pad-entry {
key "name";
ordered-by user;
description
"Peer Authorization Database (PAD) entry. It
is a list of PAD entries ordered by the
I2NSF Controller and each entry is
univocally identified by a name";
leaf name {
type string;
description
"PAD unique name to identify this
entry.";
}
choice identity {
mandatory true;
description
"A particular IKE peer will be
identified by one of these identities.
This peer can be a remote peer or local
peer (this NSF).";
reference
"Section 4.4.3.1 in RFC 4301.";
Marin-Lopez, et al. Expires September 26, 2021 [Page 37]
Internet-Draft SDN-based IPsec Flow Protection March 2021
case ipv4-address {
leaf ipv4-address {
type inet:ipv4-address;
description
"Specifies the identity as
a single four (4) octet IPv4 address.";
}
}
case ipv6-address{
leaf ipv6-address {
type inet:ipv6-address;
description
"Specifies the identity as a
single sixteen (16) octet IPv6
address. An example is
2001:db8::8:800:200c:417a.";
}
}
case fqdn-string {
leaf fqdn-string {
type inet:domain-name;
description
"Specifies the identity as a
Fully-Qualified Domain Name
(FQDN) string. An example is:
example.com. The string MUST
NOT contain any terminators
(e.g., NULL, CR, etc.).";
}
}
case rfc822-address-string {
leaf rfc822-address-string {
type string;
description
"Specifies the identity as a
fully-qualified RFC5322 email
address string. An example is,
jsmith@example.com. The string
MUST NOT contain any
terminators (e.g., NULL, CR,
etc.).";
reference
"RFC 5322.";
}
}
case dnx509 {
leaf dnx509 {
type binary;
Marin-Lopez, et al. Expires September 26, 2021 [Page 38]
Internet-Draft SDN-based IPsec Flow Protection March 2021
description
"The binary
Distinguished Encoding Rules (DER)
encoding of an ASN.1 X.500
Distinguished Name, as specified in IKEv2.";
reference
"RFC 5280. Section 3.5 in RFC 7296.";
}
}
case gnx509 {
leaf gnx509 {
type binary;
description
"ASN.1 X.509 GeneralName
structure as
specified in RFC 5280,
encoded using ASN.1
distinguished encoding rules
(DER), as specified in ITU-T
X.690.";
reference
"RFC 5280";
}
}
case id-key {
leaf id-key {
type binary;
description
"Opaque octet stream that may be
used to pass vendor-specific
information for proprietary
types of identification.";
reference
"Section 3.5 in RFC 7296.";
}
}
case id-null {
leaf id-null {
type empty;
description
"The ID_NULL identification is used
when the IKE identification payload
is not used." ;
reference
"RFC 7619.";
}
}
Marin-Lopez, et al. Expires September 26, 2021 [Page 39]
Internet-Draft SDN-based IPsec Flow Protection March 2021
}
leaf auth-protocol {
type auth-protocol-type;
default ikev2;
description
"Only IKEv2 is supported right now but
other authentication protocols may be
supported in the future.";
}
container peer-authentication {
description
"This container allows the Security
Controller to configure the
authentication method (pre-shared key,
eap, digitial-signature, null) that
will be used with a particular peer and
the credentials to use, which will
depend on the selected authentication
method.";
leaf auth-method {
type auth-method-type;
default pre-shared;
description
"Type of authentication method
(pre-shared, eap, digital signature,
null).";
reference
"Section 2.15 in RFC 7296.";
}
container eap-method {
when "../auth-method = 'eap'";
leaf eap-type {
type uint32 {range "1 .. 4294967295"; }
mandatory true;
description
"EAP method type specified with
a value extracted from the
IANA Registry. This
information provides the
particular EAP method to be
used. Depending on the EAP
method, pre-shared keys or
certificates may be used.";
}
description
"EAP method description used when
Marin-Lopez, et al. Expires September 26, 2021 [Page 40]
Internet-Draft SDN-based IPsec Flow Protection March 2021
authentication method is 'eap'.";
reference
"IANA Registry; Extensible Authentication
Protocol (EAP); Registry; Method Types.
Section 2.16 in RFC 7296.";
}
container pre-shared {
when
"../auth-method[.='pre-shared' or
.='eap']";
leaf secret {
nacm:default-deny-all;
type yang:hex-string;
description
"Pre-shared secret value. The
NSF has to prevent read access
to this value for security
reasons. This value MUST be
set if the EAP method uses a
pre-shared key or pre-shared
authentication has been chosen.";
}
description
"Shared secret value for PSK or
EAP method authentication based on
PSK.";
}
container digital-signature {
when
"../auth-method[.='digital-signature'
or .='eap']";
leaf ds-algorithm {
type uint8;
default 14;
description
"The digital signature
algorithm is specified with a
value extracted from the IANA
Registry. Default is the generic
Digital Signature method. Depending
on the algorithm, the following leafs
MUST contain information. For
example if digital signature or the
EAP method involves a certificate
then leaf 'cert-data' and 'private-key'
will contain this information.";
reference
"IANA Registry; Internet Key
Marin-Lopez, et al. Expires September 26, 2021 [Page 41]
Internet-Draft SDN-based IPsec Flow Protection March 2021
Exchange Version 2 (IKEv2);
Parameters; IKEv2 Authentication Method.";
}
choice public-key {
leaf raw-public-key {
type binary;
description
"A binary that contains the
value of the public key. The
interpretation of the content
is defined by the digital
signature algorithm. For
example, an RSA key is
represented as RSAPublicKey as
defined in RFC 8017, and an
Elliptic Curve Cryptography
(ECC) key is represented
using the 'publicKey'
described in RFC 5915.";
}
leaf cert-data {
type binary;
description
"X.509 certificate data in DER
format. If raw-public-key is
defined, this leaf is empty.";
reference "RFC 5280";
}
description
"If the I2NSF Controller
knows that the NSF
already owns a private key
associated to this public key
(e.g., the NSF generated the pair
public key/private key out of
band), it will only configure
one of the leaf of this
choice but not the leaf
private-key. The NSF, based on
the public key value, can know
the private key to be used.";
}
leaf private-key {
nacm:default-deny-all;
type binary;
description
Marin-Lopez, et al. Expires September 26, 2021 [Page 42]
Internet-Draft SDN-based IPsec Flow Protection March 2021
"A binary that contains the
value of the private key. The
interpretation of the content
is defined by the digital
signature algorithm. For
example, an RSA key is
represented as RSAPrivateKey as
defined in RFC 8017, and an
Elliptic Curve Cryptography
(ECC) key is represented as
ECPrivateKey as defined in RFC
5915. This value is set
if public-key is defined and
I2NSF controller is in charge
of configuring the
private-key. Otherwise, it is
not set and the value is
kept in secret.";
}
leaf-list ca-data {
type binary;
description
"List of trusted Certification
Authorities (CA) certificates
encoded using ASN.1
distinguished encoding rules
(DER). If it is not defined
the default value is empty.";
}
leaf crl-data {
type binary;
description
"A CertificateList structure, as
specified in RFC 5280,
encoded using ASN.1
distinguished encoding rules
(DER),as specified in ITU-T
X.690. If it is not defined
the default value is empty.";
reference
"RFC 5280";
}
leaf crl-uri {
type inet:uri;
description
"X.509 CRL certificate URI.
If it is not defined
the default value is empty.";
Marin-Lopez, et al. Expires September 26, 2021 [Page 43]
Internet-Draft SDN-based IPsec Flow Protection March 2021
reference
"RFC 5280";
}
leaf oscp-uri {
type inet:uri;
description
"OCSP URI.
If it is not defined
the default value is empty.";
reference
"RFC 2560 and RFC 5280";
}
description
"Digital Signature container.";
} /*container digital-signature*/
} /*container peer-authentication*/
}
}
list conn-entry {
key "name";
description
"IKE peer connection information. This list
contains the IKE connection for this peer
with other peers. This will create in
real time IKE Security Associations
established with these nodes.";
leaf name {
type string;
description
"Identifier for this connection
entry.";
}
leaf autostartup {
type autostartup-type;
default add;
description
"By-default: Only add configuration
without starting the security
association.";
}
leaf initial-contact {
type boolean;
default false;
description
"The goal of this value is to deactivate the
usage of INITIAL_CONTACT notification
(true). If this flag remains to false it
Marin-Lopez, et al. Expires September 26, 2021 [Page 44]
Internet-Draft SDN-based IPsec Flow Protection March 2021
means the usage of the INITIAL_CONTACT
notification will depend on the IKEv2
implementation.";
}
leaf version {
type auth-protocol-type;
default ikev2;
description
"IKE version. Only version 2 is supported.";
}
container fragmentation {
leaf enable {
type boolean;
default false;
description
"Whether or not to enable IKEv2
fragmentation (true or
false).";
reference
"RFC 7383.";
}
leaf mtu {
when "../enable='true'";
type uint16 { range "68..65535"; }
description
"MTU that IKEv2 can use
for IKEv2 fragmentation.";
reference
"RFC 7383.";
}
description
"IKEv2 fragmentation as per RFC 7383. If the
IKEv2 fragmentation is enabled it is possible
to specify the MTU.";
}
container ike-sa-lifetime-soft {
description
"IKE SA lifetime soft. Two lifetime values
can be configured: either rekey time of the
IKE SA or reauth time of the IKE SA. When
the rekey lifetime expires a rekey of the
IKE SA starts. When reauth lifetime
expires a IKE SA reauthentication starts.";
leaf rekey-time {
type uint32;
units "seconds";
Marin-Lopez, et al. Expires September 26, 2021 [Page 45]
Internet-Draft SDN-based IPsec Flow Protection March 2021
default 0;
description
"Time in seconds between each IKE SA
rekey. The value 0 means infinite.";
}
leaf reauth-time {
type uint32;
units "seconds";
default 0;
description
"Time in seconds between each IKE SA
reauthentication. The value 0 means
infinite.";
}
reference
"Section 2.8 in RFC 7296.";
}
container ike-sa-lifetime-hard {
description
"Hard IKE SA lifetime. When this
time is reached the IKE SA is removed.";
leaf over-time {
type uint32;
units "seconds";
default 0;
description
"Time in seconds before the IKE SA is
removed. The value 0 means infinite.";
}
reference
"RFC 7296.";
}
leaf-list ike-sa-intr-alg {
type nsfikec:intr-alg-t;
default 12;
ordered-by user;
description
"Integrity algorithm for establishing
the IKE SA. This list is ordered following
from the higher priority to lower priority.
First node of the list will be the algorithm
with higher priority.
Default value 12 (AUTH_HMAC_SHA2_256_128)";
}
list ike-sa-encr-alg {
key id;
min-elements 1;
ordered-by user;
Marin-Lopez, et al. Expires September 26, 2021 [Page 46]
Internet-Draft SDN-based IPsec Flow Protection March 2021
leaf id {
type uint16;
description
"An identifier that unequivocally
identifies each entry of the list,
i.e., an encryption algorithm and
its key-length (if required)";
}
leaf algorithm-type {
type nsfikec:encr-alg-t;
default 12;
description
"Default value 12 (ENCR_AES_CBC)";
}
leaf key-length {
type uint16;
default 128;
description
"By default key length is 128 bits";
}
description
"Encryption or AEAD algorithm for the IKE
SAs. This list is ordered following
from the higher priority to lower priority.
First node of the list will be the algorithm
with higher priority";
}
leaf dh-group {
type fs-group;
default 14;
description
"Group number for Diffie-Hellman
Exponentiation used during IKE_SA_INIT
for the IKE SA key exchange.";
}
leaf half-open-ike-sa-timer {
type uint32;
units "seconds";
default 0;
description
"Set the half-open IKE SA timeout
duration. The value 0 implies infinite.";
reference
"Section 2 in RFC 7296.";
}
leaf half-open-ike-sa-cookie-threshold {
type uint32;
default 0;
Marin-Lopez, et al. Expires September 26, 2021 [Page 47]
Internet-Draft SDN-based IPsec Flow Protection March 2021
description
"Number of half-open IKE SAs that activate
the cookie mechanism. The value 0 implies
infinite." ;
reference
"Section 2.6 in RFC 7296.";
}
container local {
leaf local-pad-entry-name {
type string;
mandatory true;
description
"Local peer authentication information.
This node points to a specific entry in
the PAD where the authorization
information about this particular local
peer is stored. It MUST match a
pad-entry-name.";
}
description
"Local peer authentication information.";
}
container remote {
leaf remote-pad-entry-name {
type string;
mandatory true;
description
"Remote peer authentication information.
This node points to a specific entry in
the PAD where the authorization
information about this particular
remote peer is stored. It MUST match a
pad-entry-name.";
}
description
"Remote peer authentication information.";
}
container encapsulation-type {
uses nsfikec:encap;
description
"This container carries configuration
information about the source and destination
ports of encapsulation that IKE should use
and the type of encapsulation that
should use when NAT traversal is required.
However, this is just a best effort since
the IKE implementation may need to use a
different encapsulation as
Marin-Lopez, et al. Expires September 26, 2021 [Page 48]
Internet-Draft SDN-based IPsec Flow Protection March 2021
described in RFC 8229.";
reference
"RFC 8229.";
}
container spd {
description
"Configuration of the Security Policy
Database (SPD). This main information is
placed in the grouping
ipsec-policy-grouping.";
list spd-entry {
key "name";
ordered-by user;
leaf name {
type string;
description
"SPD entry unique name to identify
the IPsec policy.";
}
container ipsec-policy-config {
description
"This container carries the
configuration of a IPsec policy.";
uses nsfikec:ipsec-policy-grouping;
}
description
"List of entries which will constitute
the representation of the SPD. In this
case, since the NSF implements IKE, it
is only required to send a IPsec policy
from this NSF where 'local' is this NSF
and 'remote' the other NSF. The IKE
implementation will install IPsec
policies in the NSF's kernel in both
directions (inbound and outbound) and
their corresponding IPsec SAs based on
the information in this SPD entry.";
}
reference
"Section 2.9 in RFC 7296.";
}
container child-sa-info {
leaf-list fs-groups {
type fs-group;
default 0;
ordered-by user;
description
"If non-zero, forward secrecy is
Marin-Lopez, et al. Expires September 26, 2021 [Page 49]
Internet-Draft SDN-based IPsec Flow Protection March 2021
required when a new IPsec SA is being
created. The (non-zero) value indicates
the group number to use for the key
exchange process used to achieve forward
secrecy.
This list is ordered following from the
higher priority to lower priority. First
node of the list will be the algorithm
with higher priority.";
}
container child-sa-lifetime-soft {
description
"Soft IPsec SA lifetime.
After the lifetime the action is
defined in this container
in the leaf action.";
uses nsfikec:lifetime;
leaf action {
type nsfikec:lifetime-action;
default replace;
description
"When the lifetime of an IPsec SA
expires an action needs to be
performed over the IPsec SA that
reached the lifetime. There are
three possible options:
terminate-clear, terminate-hold and
replace.";
reference
"Section 4.5 in RFC 4301 and Section 2.8
in RFC 7296.";
}
}
container child-sa-lifetime-hard {
description
"IPsec SA lifetime hard. The action will
be to terminate the IPsec SA.";
uses nsfikec:lifetime;
reference
"Section 2.8 in RFC 7296.";
}
description
"Specific information for IPsec SAs
SAs. It includes PFS group and IPsec SAs
rekey lifetimes.";
}
container state {
config false;
Marin-Lopez, et al. Expires September 26, 2021 [Page 50]
Internet-Draft SDN-based IPsec Flow Protection March 2021
leaf initiator {
type boolean;
description
"It is acting as initiator for this
connection.";
}
leaf initiator-ikesa-spi {
type ike-spi;
description
"Initiator's IKE SA SPI.";
}
leaf responder-ikesa-spi {
type ike-spi;
description
"Responder's IKE SA SPI.";
}
leaf nat-local {
type boolean;
description
"True, if local endpoint is behind a
NAT.";
}
leaf nat-remote {
type boolean;
description
"True, if remote endpoint is behind
a NAT.";
}
container encapsulation-type {
uses nsfikec:encap;
description
"This container provides information
about the source and destination
ports of encapsulation that IKE is
using, and the type of encapsulation
when NAT traversal is required.";
reference
"RFC 8229.";
}
leaf established {
type uint64;
units "seconds";
description
"Seconds since this IKE SA has been
established.";
}
leaf current-rekey-time {
type uint64;
Marin-Lopez, et al. Expires September 26, 2021 [Page 51]
Internet-Draft SDN-based IPsec Flow Protection March 2021
units "seconds";
description
"Seconds before IKE SA is rekeyed.";
}
leaf current-reauth-time {
type uint64;
units "seconds";
description
"Seconds before IKE SA is
re-authenticated.";
}
description
"IKE state data for a particular
connection.";
} /* ike-sa-state */
} /* ike-conn-entries */
container number-ike-sas {
config false;
leaf total {
type yang:gauge64;
description
"Total number of active IKE SAs.";
}
leaf half-open {
type yang:gauge64;
description
"Number of half-open active IKE SAs.";
}
leaf half-open-cookies {
type yang:gauge64;
description
"Number of half open active IKE SAs with
cookie activated.";
}
description
"General information about the IKE SAs. In
particular, it provides the current number of
IKE SAs.";
}
} /* container ipsec-ike */
}
<CODE ENDS>
Marin-Lopez, et al. Expires September 26, 2021 [Page 52]
Internet-Draft SDN-based IPsec Flow Protection March 2021
6.3. The 'ietf-i2nsf-ikeless' Module
In this section, the YANG module for the IKE-less case is described.
6.3.1. Data model overview
For this case, the definition of the SPD model has been mainly
extracted from the specification in section 4.4.1 and Appendix D in
[RFC4301], though with some changes, namely:
o For simplicity, each IPsec policy (spd-entry) contains one traffic
selector, instead of a list of them. The reason is that actual
kernel implementations only admit a single traffic selector per
IPsec policy.
o Each IPsec policy contains an identifier (reqid) to relate the
policy with the IPsec SA. This is common in Linux-based systems.
o Each IPsec policy has only one name and not a list of names.
o Combined algorithms have been removed because encryption
algorithms MAY include authenticated encryption with associated
data (AEAD).
o Tunnel information has been extended with information about DSCP
mapping. The reason is that certain kernel implementations accept
configuration of these values.
The definition of the SAD model has been mainly extracted from the
specification in section 4.4.2 in [RFC4301] though with some changes,
namely:
o For simplicity, each IPsec SA (sad-entry) contains one traffic
selector, instead of a list of them. The reason is that actual
kernel implementations only admit a single traffic selector per
IPsec SA.
o Each IPsec SA contains a identifier (reqid) to relate the IPsec SA
with the IPsec Policy. The reason is that real kernel
implementations allow to include this value.
o Each IPsec SA has also a name in the same way as IPsec policies.
o The model allows specifying the algorithm for encryption. This
can be an Authenticated Encryption with Associated Data (AEAD) or
non-AEAD. If an AEAD is specified the integrity algorithm is not
required. If an non-AEAD algorithm is specified the integrity
algorithm is required [RFC8221].
Marin-Lopez, et al. Expires September 26, 2021 [Page 53]
Internet-Draft SDN-based IPsec Flow Protection March 2021
o Tunnel information has been extended with information about
Differentiated Services Code Point (DSCP) mapping. It is assumed
that NSFs involved in this document provide ECN full-functionality
to prevent discarding of ECN congestion indications [RFC6040].
o Lifetime of the IPsec SAs also include idle time and number of IP
packets as threshold to trigger the lifetime. The reason is that
actual kernel implementations allow to set these types of
lifetimes.
o Information to configure the type of encapsulation (encapsulation-
type) for IPsec ESP packets in UDP ([RFC3948]), or TCP ([RFC8229])
has been included.
The notifications model has been defined using as reference the
PF_KEYv2 specification in [RFC2367].
The YANG data model for the IKE-less case is defined by the module
"ietf-i2nsf-ikeless". Its structure is depicted in the following
diagram, using the notation syntax for YANG tree diagrams
([RFC8340]).
module: ietf-i2nsf-ikeless
+--rw ipsec-ikeless
+--rw spd
| +--rw spd-entry* [name]
| +--rw name string
| +--rw direction nsfikec:ipsec-traffic-direction
| +--rw reqid? uint64
| +--rw ipsec-policy-config
| +--rw anti-replay-window-size? uint32
| +--rw traffic-selector
| | +--rw local-prefix inet:ip-prefix
| | +--rw remote-prefix inet:ip-prefix
| | +--rw inner-protocol? ipsec-inner-protocol
| | +--rw local-ports* [start end]
| | | +--rw start inet:port-number
| | | +--rw end inet:port-number
| | +--rw remote-ports* [start end]
| | +--rw start inet:port-number
| | +--rw end inet:port-number
| +--rw processing-info
| +--rw action? ipsec-spd-action
| +--rw ipsec-sa-cfg
| +--rw pfp-flag? boolean
| +--rw ext-seq-num? boolean
| +--rw seq-overflow? boolean
Marin-Lopez, et al. Expires September 26, 2021 [Page 54]
Internet-Draft SDN-based IPsec Flow Protection March 2021
| +--rw stateful-frag-check? boolean
| +--rw mode? ipsec-mode
| +--rw protocol-parameters? ipsec-protocol-parameters
| +--rw esp-algorithms
| | +--rw integrity* intr-alg-t
| | +--rw encryption* [id]
| | | +--rw id uint16
| | | +--rw algorithm-type? encr-alg-t
| | | +--rw key-length? uint16
| | +--rw tfc-pad? boolean
| +--rw tunnel
| +--rw local inet:ip-address
| +--rw remote inet:ip-address
| +--rw df-bit? enumeration
| +--rw bypass-dscp? boolean
| +--rw dscp-mapping* [id]
| +--rw id uint8
| +--rw inner-dscp? inet:dscp
| +--rw outer-dscp? inet:dscp
+--rw sad
+--rw sad-entry* [name]
+--rw name string
+--rw reqid? uint64
+--rw ipsec-sa-config
| +--rw spi uint32
| +--rw ext-seq-num? boolean
| +--rw seq-overflow? boolean
| +--rw anti-replay-window-size? uint32
| +--rw traffic-selector
| | +--rw local-prefix inet:ip-prefix
| | +--rw remote-prefix inet:ip-prefix
| | +--rw inner-protocol? ipsec-inner-protocol
| | +--rw local-ports* [start end]
| | | +--rw start inet:port-number
| | | +--rw end inet:port-number
| | +--rw remote-ports* [start end]
| | +--rw start inet:port-number
| | +--rw end inet:port-number
| +--rw protocol-parameters? nsfikec:ipsec-protocol-parameters
| +--rw mode? nsfikec:ipsec-mode
| +--rw esp-sa
| | +--rw encryption
| | | +--rw encryption-algorithm? nsfikec:encr-alg-t
| | | +--rw key? yang:hex-string
| | | +--rw iv? yang:hex-string
| | +--rw integrity
| | +--rw integrity-algorithm? nsfikec:intr-alg-t
| | +--rw key? yang:hex-string
Marin-Lopez, et al. Expires September 26, 2021 [Page 55]
Internet-Draft SDN-based IPsec Flow Protection March 2021
| +--rw sa-lifetime-hard
| | +--rw time? uint32
| | +--rw bytes? yang:counter64
| | +--rw packets? uint32
| | +--rw idle? uint32
| +--rw sa-lifetime-soft
| | +--rw time? uint32
| | +--rw bytes? yang:counter64
| | +--rw packets? uint32
| | +--rw idle? uint32
| | +--rw action? nsfikec:lifetime-action
| +--rw tunnel
| | +--rw local inet:ip-address
| | +--rw remote inet:ip-address
| | +--rw df-bit? enumeration
| | +--rw bypass-dscp? boolean
| | +--rw dscp-mapping* [id]
| | | +--rw id uint8
| | | +--rw inner-dscp? inet:dscp
| | | +--rw outer-dscp? inet:dscp
| | +--rw dscp-values* inet:dscp
| +--rw encapsulation-type
| +--rw espencap? esp-encap
| +--rw sport? inet:port-number
| +--rw dport? inet:port-number
| +--rw oaddr* inet:ip-address
+--ro ipsec-sa-state
+--ro sa-lifetime-current
| +--ro time? uint32
| +--ro bytes? yang:counter64
| +--ro packets? uint32
| +--ro idle? uint32
+--ro replay-stats
+--ro replay-window
| +--ro w? uint32
| +--ro t? uint64
| +--ro b? uint64
+--ro packet-dropped? yang:counter64
+--ro failed? yang:counter64
+--ro seq-number-counter? uint64
notifications:
+---n sadb-acquire {ikeless-notification}?
| +--ro ipsec-policy-name string
| +--ro traffic-selector
| +--ro local-prefix inet:ip-prefix
| +--ro remote-prefix inet:ip-prefix
| +--ro inner-protocol? ipsec-inner-protocol
Marin-Lopez, et al. Expires September 26, 2021 [Page 56]
Internet-Draft SDN-based IPsec Flow Protection March 2021
| +--ro local-ports* [start end]
| | +--ro start inet:port-number
| | +--ro end inet:port-number
| +--ro remote-ports* [start end]
| +--ro start inet:port-number
| +--ro end inet:port-number
+---n sadb-expire {ikeless-notification}?
| +--ro ipsec-sa-name string
| +--ro soft-lifetime-expire? boolean
| +--ro lifetime-current
| +--ro time? uint32
| +--ro bytes? yang:counter64
| +--ro packets? uint32
| +--ro idle? uint32
+---n sadb-seq-overflow {ikeless-notification}?
| +--ro ipsec-sa-name string
+---n sadb-bad-spi {ikeless-notification}?
+--ro spi uint32
The YANG data model consists of a unique "ipsec-ikeless" container
which, in turn, is composed of two additional containers: "spd" and
"sad". The "spd" container consists of a list of entries that form
the Security Policy Database. Compared to the IKE case YANG data
model, this part specifies a few additional parameters necessary due
to the absence of an IKE software in the NSF: traffic direction to
apply the IPsec policy, and a "reqid" value to link an IPsec policy
with its associated IPsec SAs since it is otherwise a little hard to
find by searching. The "sad" container is a list of entries that
form the Security Association Database. In general, each entry
allows specifying both configuration information (SPI, traffic
selectors, tunnel/transport mode, cryptographic algorithms and keying
material, soft/hard lifetimes, etc.) as well as state information
(time to expire, replay statistics, etc.) of a concrete IPsec SA.
In addition, the module defines a set of notifications to allow the
NSF inform I2NSF controller about relevant events such as IPsec SA
expiration, sequence number overflow or bad SPI in a received packet.
6.3.2. Example Usage
Appendix B shows an example of IKE-less case configuration for a NSF,
in transport mode (host-to-host). Additionally, Appendix C shows
examples of IPsec SA expire, acquire, sequence number overflow and
bad SPI notifications.
Marin-Lopez, et al. Expires September 26, 2021 [Page 57]
Internet-Draft SDN-based IPsec Flow Protection March 2021
6.3.3. YANG Module
This YANG module has normative references to [RFC4301], [RFC6991],
[RFC8174] and [RFC8341].
<CODE BEGINS> file "ietf-i2nsf-ikeless@2021-03-18.yang"
module ietf-i2nsf-ikeless {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikeless";
prefix "nsfikels";
import ietf-inet-types {
prefix inet;
reference "RFC 6991: Common YANG Data Types";
}
import ietf-yang-types {
prefix yang;
reference "RFC 6991: Common YANG Data Types";
}
import ietf-i2nsf-ikec {
prefix nsfikec;
reference
"RFC XXXX: Software-Defined Networking
(SDN)-based IPsec Flow Protection.";
}
import ietf-netconf-acm {
prefix nacm;
reference
"RFC 8341: Network Configuration Access Control
Model.";
}
organization "IETF I2NSF Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/i2nsf/>
WG List: <mailto:i2nsf@ietf.org>
Author: Rafael Marin-Lopez
<mailto:rafa@um.es>
Marin-Lopez, et al. Expires September 26, 2021 [Page 58]
Internet-Draft SDN-based IPsec Flow Protection March 2021
Author: Gabriel Lopez-Millan
<mailto:gabilm@um.es>
Author: Fernando Pereniguez-Garcia
<mailto:fernando.pereniguez@cud.upct.es>
";
description
"Data model for IKE-less case in the SDN-base IPsec flow
protection service.
Copyright (c) 2020 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
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX;;
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 "2021-03-18" {
description "Initial version.";
reference
"RFC XXXX: Software-Defined Networking
(SDN)-based IPsec Flow Protection.";
}
feature ikeless-notification {
description
"This feature indicates that the server supports
generating notifications in the ikeless module.
To ensure broader applicability of this module,
the notifications are marked as a feature.
For the implementation of ikeless case,
the NSF is expected to implement this
feature.";
}
Marin-Lopez, et al. Expires September 26, 2021 [Page 59]
Internet-Draft SDN-based IPsec Flow Protection March 2021
container ipsec-ikeless {
description
"Container for configuration of the IKE-less
case. The container contains two additional
containers: 'spd' and 'sad'. The first allows the
I2NSF Controller to configure IPsec policies in
the Security Policy Database SPD, and the second
allows to configure IPsec Security Associations
(IPsec SAs) in the Security Association Database
(SAD).";
reference "RFC 4301.";
container spd {
description
"Configuration of the Security Policy Database
(SPD.)";
reference "Section 4.4.1.2 in RFC 4301.";
list spd-entry {
key "name";
ordered-by user;
leaf name {
type string;
description
"SPD entry unique name to identify this
entry.";
}
leaf direction {
type nsfikec:ipsec-traffic-direction;
mandatory true;
description
"Inbound traffic or outbound
traffic. In the IKE-less case the
I2NSF Controller needs to
specify the policy direction to be
applied in the NSF. In the IKE case
this direction does not need to be
specified since IKE
will determine the direction that
IPsec policy will require.";
}
leaf reqid {
type uint64;
default 0;
description
"This value allows to link this
IPsec policy with IPsec SAs with the
same reqid. It is only required in
Marin-Lopez, et al. Expires September 26, 2021 [Page 60]
Internet-Draft SDN-based IPsec Flow Protection March 2021
the IKE-less model since, in the IKE
case this link is handled internally
by IKE.";
}
container ipsec-policy-config {
description
"This container carries the
configuration of a IPsec policy.";
uses nsfikec:ipsec-policy-grouping;
}
description
"The SPD is represented as a list of SPD
entries, where each SPD entry represents an
IPsec policy.";
} /*list spd-entry*/
} /*container spd*/
container sad {
description
"Configuration of the IPsec Security Association
Database (SAD)";
reference "Section 4.4.2.1 in RFC 4301.";
list sad-entry {
key "name";
ordered-by user;
leaf name {
type string;
description
"SAD entry unique name to identify this
entry.";
}
leaf reqid {
type uint64;
default 0;
description
"This value allows to link this
IPsec SA with an IPsec policy with
the same reqid.";
}
container ipsec-sa-config {
description
"This container allows configuring
details of an IPsec SA.";
leaf spi {
type uint32 { range "0..max"; }
Marin-Lopez, et al. Expires September 26, 2021 [Page 61]
Internet-Draft SDN-based IPsec Flow Protection March 2021
mandatory true;
description
"Security Parameter Index (SPI)'s
IPsec SA.";
}
leaf ext-seq-num {
type boolean;
default true;
description
"True if this IPsec SA is using extended
sequence numbers. If true, the 64-bit
extended sequence number counter is used;
if false, the normal 32-bit sequence
number counter is used.";
}
leaf seq-overflow {
type boolean;
default false;
description
"The flag indicating whether
overflow of the sequence number
counter should prevent transmission
of additional packets on the IPsec
SA (false) and, therefore needs to
be rekeyed, or whether rollover is
permitted (true). If Authenticated
Encryption with Associated Data
(AEAD) is used (leaf
esp-algorithms/encryption/algorithm-type)
this flag MUST BE false. Setting this
flag to true is strongly discouraged.";
}
leaf anti-replay-window-size {
type uint32;
default 64;
description
"To set the anti-replay window size.
The default value is set to 64
following RFC 4303 recommendation.";
reference
"Section 3.4.3 in RFC 4303";
}
container traffic-selector {
uses nsfikec:selector-grouping;
description
"The IPsec SA traffic selector.";
Marin-Lopez, et al. Expires September 26, 2021 [Page 62]
Internet-Draft SDN-based IPsec Flow Protection March 2021
}
leaf protocol-parameters {
type nsfikec:ipsec-protocol-parameters;
default esp;
description
"Security protocol of IPsec SA: Only
ESP so far.";
}
leaf mode {
type nsfikec:ipsec-mode;
default transport;
description
"Tunnel or transport mode.";
}
container esp-sa {
when "../protocol-parameters = 'esp'";
description
"In case the IPsec SA is
Encapsulation Security Payload
(ESP), it is required to specify
encryption and integrity
algorithms, and key material.";
container encryption {
description
"Configuration of encryption or
AEAD algorithm for IPsec
Encapsulation Security Payload
(ESP).";
leaf encryption-algorithm {
type nsfikec:encr-alg-t;
default 12;
description
"Configuration of ESP
encryption. With AEAD
algorithms, the integrity-algorithm
leaf is not used.";
}
leaf key {
nacm:default-deny-all;
type yang:hex-string;
description
"ESP encryption key value.
If this leaf is not defined
the key is not defined
(e.g., encryption is NULL).
Marin-Lopez, et al. Expires September 26, 2021 [Page 63]
Internet-Draft SDN-based IPsec Flow Protection March 2021
The key length is
determined by the
length of the key set in
this leaf. By default is
128 bits.";
}
leaf iv {
nacm:default-deny-all;
type yang:hex-string;
description
"ESP encryption IV value. If
this leaf is not defined the
IV is not defined (e.g.,
encryption is NULL)";
}
}
container integrity {
description
"Configuration of integrity for
IPsec Encapsulation Security
Payload (ESP). This container
allows configuration of integrity
algorithms when no AEAD
algorithms are used, and
integrity is required.";
leaf integrity-algorithm {
type nsfikec:intr-alg-t;
default 12;
description
"Message Authentication Code
(MAC) algorithm to provide
integrity in ESP
(default
AUTH_HMAC_SHA2_256_128).
With AEAD algorithms,
the integrity leaf is not
used.";
}
leaf key {
nacm:default-deny-all;
type yang:hex-string;
description
"ESP integrity key value.
If this leaf is not defined
the key is not defined (e.g.,
Marin-Lopez, et al. Expires September 26, 2021 [Page 64]
Internet-Draft SDN-based IPsec Flow Protection March 2021
AEAD algorithm is chosen and
integrity algorithm is not
required). The key length is
determined by the length of
the key configured.";
}
}
} /*container esp-sa*/
container sa-lifetime-hard {
description
"IPsec SA hard lifetime. The action
associated is terminate and
hold.";
uses nsfikec:lifetime;
}
container sa-lifetime-soft {
description
"IPsec SA soft lifetime.";
uses nsfikec:lifetime;
leaf action {
type nsfikec:lifetime-action;
description
"Action lifetime:
terminate-clear,
terminate-hold or replace.";
}
}
container tunnel {
when "../mode = 'tunnel'";
uses nsfikec:tunnel-grouping;
leaf-list dscp-values {
type inet:dscp;
description
"DSCP values allowed for ingress packets carried
over this IPsec SA. If no values are specified, no
DSCP-specific filtering is applied. When
../bypass-dscp is false and a dscp-mapping is
defined, each value here would be the same as the
'inner' DSCP value for the DSCP mapping (list
dscp-mapping)";
reference
"Section 4.4.2.1. in RFC 4301.";
}
description
"Endpoints of the IPsec tunnel.";
}
container encapsulation-type {
Marin-Lopez, et al. Expires September 26, 2021 [Page 65]
Internet-Draft SDN-based IPsec Flow Protection March 2021
uses nsfikec:encap;
description
"This container carries
configuration information about
the source and destination ports
which will be used for ESP
encapsulation that ESP packets the
type of encapsulation when NAT
traversal is in place.";
}
} /*ipsec-sa-config*/
container ipsec-sa-state {
config false;
description
"Container describing IPsec SA state
data.";
container sa-lifetime-current {
uses nsfikec:lifetime;
description
"SAD lifetime current.";
}
container replay-stats {
description
"State data about the anti-replay
window.";
container replay-window {
leaf w {
type uint32;
description
"Size of the replay window.";
}
leaf t {
type uint64;
description
"Highest sequence number
authenticated so far,
upper bound of window.";
}
leaf b {
type uint64;
description
"Lower bound of window.";
}
description
"This container contains three
parameters that defines the state
Marin-Lopez, et al. Expires September 26, 2021 [Page 66]
Internet-Draft SDN-based IPsec Flow Protection March 2021
of the replay window: window size (w),
highest sequence number authenticated (t)
and lower bound of the window (b). According
to Appendix A2.1 - RFC 4303 w = t-b+1.";
reference
"Appendix A in RFC 4303.";
}
leaf packet-dropped {
type yang:counter64;
description
"Packets dropped
because they are
replay packets.";
}
leaf failed {
type yang:counter64;
description
"Number of packets detected out
of the replay window.";
}
leaf seq-number-counter {
type uint64;
description
"A 64-bit counter when this
IPsec SA is using Extended
Sequence Number or 32-bit
counter when it is not.
Current value of sequence
number.";
}
} /* container replay-stats*/
} /*ipsec-sa-state*/
description
"List of SAD entries that forms the SAD.";
} /*list sad-entry*/
} /*container sad*/
}/*container ipsec-ikeless*/
/* Notifications */
notification sadb-acquire {
if-feature ikeless-notification;
description
"The NSF detects and notifies that
an IPsec SA is required for an
Marin-Lopez, et al. Expires September 26, 2021 [Page 67]
Internet-Draft SDN-based IPsec Flow Protection March 2021
outbound IP packet that has matched a SPD entry.
The traffic-selector container in this
notification contains information about
the IP packet that triggered this
notification.";
leaf ipsec-policy-name {
type string;
mandatory true;
description
"It contains the SPD entry name (unique) of
the IPsec policy that hits the IP packet
required IPsec SA. It is assumed the
I2NSF Controller will have a copy of the
information of this policy so it can
extract all the information with this
unique identifier. The type of IPsec SA is
defined in the policy so the Security
Controller can also know the type of IPsec
SA that MUST be generated.";
}
container traffic-selector {
description
"The IP packet that triggered the acquire
and requires an IPsec SA. Specifically it
will contain the IP source/mask and IP
destination/mask; protocol (udp, tcp,
etc...); and source and destination
ports.";
uses nsfikec:selector-grouping;
}
}
notification sadb-expire {
if-feature ikeless-notification;
description "An IPsec SA expiration (soft or hard).";
leaf ipsec-sa-name {
type string;
mandatory true;
description
"It contains the SAD entry name (unique) of
the IPsec SA that is about to expire. It is assumed
the I2NSF Controller will have a copy of the
IPsec SA information (except the cryptographic
material and state data) indexed by this name
(unique identifier) so it can know all the
information (crypto algorithms, etc.) about
the IPsec SA that has expired in order to
perform a rekey (soft lifetime) or delete it
Marin-Lopez, et al. Expires September 26, 2021 [Page 68]
Internet-Draft SDN-based IPsec Flow Protection March 2021
(hard lifetime) with this unique identifier.";
}
leaf soft-lifetime-expire {
type boolean;
default true;
description
"If this value is true the lifetime expired is
soft. If it is false is hard.";
}
container lifetime-current {
description
"IPsec SA current lifetime. If
soft-lifetime-expired is true
this container is set with the
lifetime information about current
soft lifetime.
It can help the NSF Controller
to know which of the (soft) lifetime
limits raised the event: time, bytes,
packets or idle.";
uses nsfikec:lifetime;
}
}
notification sadb-seq-overflow {
if-feature ikeless-notification;
description "Sequence overflow notification.";
leaf ipsec-sa-name {
type string;
mandatory true;
description
"It contains the SAD entry name (unique) of
the IPsec SA that is about to have a sequence
number overflow and rollover is not permitted.
When the NSF issues this event before reaching
a sequence number overflow is implementation
specific and out of scope of this specification.
It is assumed the I2NSF Controller will have a
copy of the IPsec SA information (except the
cryptographic material and state data) indexed
by this name (unique identifier) so it can
know all the information (crypto algorithms,
etc.) about the IPsec SA in
order to perform a rekey of the IPsec SA.";
}
}
Marin-Lopez, et al. Expires September 26, 2021 [Page 69]
Internet-Draft SDN-based IPsec Flow Protection March 2021
notification sadb-bad-spi {
if-feature ikeless-notification;
description
"Notify when the NSF receives a packet with an
incorrect SPI (i.e. not present in the SAD).";
leaf spi {
type uint32 { range "0..max"; }
mandatory true;
description
"SPI number contained in the erroneous IPsec
packet.";
}
}
}
<CODE ENDS>
7. IANA Considerations
This document registers three URIs in the "ns" subregistry of the
IETF XML Registry [RFC3688]. Following the format in [RFC3688], the
following registrations are requested:
URI: urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikec
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
URI: urn:ietf:params:xml:ns:yang:ietf-i2nsf-ike
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
URI: urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikeless
Registrant Contact: The IESG.
XML: N/A, the requested URI is an XML namespace.
This document registers three YANG modules in the "YANG Module Names"
registry [RFC6020]. Following the format in [RFC6020], the following
registrations are requested:
Marin-Lopez, et al. Expires September 26, 2021 [Page 70]
Internet-Draft SDN-based IPsec Flow Protection March 2021
Name: ietf-i2nsf-ikec
Namespace: urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikec
Prefix: nsfikec
Reference: RFC XXXX
Name: ietf-i2nsf-ike
Namespace: urn:ietf:params:xml:ns:yang:ietf-i2nsf-ike
Prefix: nsfike
Reference: RFC XXXX
Name: ietf-i2nsf-ikeless
Namespace: urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikeless
Prefix: nsfikels
Reference: RFC XXXX
8. Security Considerations
First of all, this document shares all the security issues of SDN
that are specified in the "Security Considerations" section of
[ITU-T.Y.3300] and [RFC7426].
On the one hand, it is important to note that there MUST exist a
security association between the I2NSF Controller and the NSFs to
protect the critical information (cryptographic keys, configuration
parameter, etc.) exchanged between these entities. The nature of and
means to create that security association is out of the scope of this
document (i.e., it is part of device provisioning or onboarding).
On the other hand, if encryption is mandatory for all traffic of a
NSF, its default policy MUST be to drop (DISCARD) packets to prevent
cleartext packet leaks. This default policy MUST be pre-configured
in the startup configuration datastore in the NSF before the NSF
contacts the I2NSF Controller. Moreover, the startup configuration
datastore MUST be also pre-configured with the required ALLOW
policies that allow the NSF to communicate with the I2NSF Controller
once the NSF is deployed. This pre-configuration step is not carried
out by the I2NSF Controller but by some other entity before the NSF
deployment. In this manner, when the NSF starts/reboots, it will
always first apply the configuration in the startup configuration
before contacting the I2NSF Controller.
Finally, this section is divided in two parts in order to analyze
different security considerations for both cases: NSF with IKEv2 (IKE
case) and NSF without IKEv2 (IKE-less case). In general, the I2NSF
Controller, as typically in the SDN paradigm, is a target for
different type of attacks [SDNSecServ] and [SDNSecurity]. Thus, the
I2NSF Controller is a key entity in the infrastructure and MUST be
protected accordingly. In particular, the I2NSF Controller will
Marin-Lopez, et al. Expires September 26, 2021 [Page 71]
Internet-Draft SDN-based IPsec Flow Protection March 2021
handle cryptographic material thus the attacker may try to access
this information. The impact is different depending on the IKE case
or the IKE-less case.
8.1. IKE case
In the IKE case, the I2NSF Controller sends IKEv2 credentials (PSK,
public/private keys, certificates, etc.) to the NSFs using the
security association between I2NSF Controller and NSFs. The I2NSF
Controller MUST NOT store the IKEv2 credentials after distributing
them. Moreover, the NSFs MUST NOT allow the reading of these values
once they have been applied by the I2NSF Controller (i.e. write only
operations). One option is to always return the same value (i.e. all
0s) if a read operation is carried out.
If the attacker has access to the I2NSF Controller during the period
of time that key material is generated, it might have access to the
key material. Since these values are used during NSF authentication
in IKEv2, it may impersonate the affected NSFs. Several
recommendations are important.
o IKEv2 configurations SHOULD adhere to the recommendations in
[RFC8247].
o If PSK authentication is used in IKEv2, the I2NSF Controller MUST
remove the PSK immediately after generating and distributing it.
o When public/private keys are used, the I2NSF Controller MAY
generate both public key and private key. In such a case, the
I2NSF Controller MUST remove the associated private key
immediately after distributing them to the NSFs. Alternatively,
the NSF MAY generate the private key and export only the public
key to the I2NSF Controller. How the NSF generates these
cryptographic material (public key/ private keys) and exports the
public key, is out of scope of this document.
o If certificates are used, the NSF MAY generate the private key and
export the public key for certification to the I2NSF Controller.
How the NSF generates these cryptographic material (public key/
private keys) and exports the public key, is out of scope of this
document.
8.2. IKE-less case
In the IKE-less case, the I2NSF Controller sends the IPsec SA
information to the NSF's SAD that includes the private session keys
required for integrity and encryption. The I2NSF Controller MUST NOT
store the keys after distributing them. Moreover, the NSFs receiving
Marin-Lopez, et al. Expires September 26, 2021 [Page 72]
Internet-Draft SDN-based IPsec Flow Protection March 2021
private key material MUST NOT allow the reading of these values by
any other entity (including the I2NSF Controller itself) once they
have been applied (i.e. write only operations) into the NSFs.
Nevertheless, if the attacker has access to the I2NSF Controller
during the period of time that key material is generated, it may
obtain these values. In other words, the attacker might be able to
observe the IPsec traffic and decrypt, or even modify and re-encrypt,
the traffic between peers.
Finally, the security association between the I2NSF Controller and
the NSFs MUST provide, at least, the same degree of protection as the
one achieved by the IPsec SAs configured in the NSFs. In particular,
the security association between the I2NSF Controller and the NSFs
MUST provide forward secrecy if this property is to be achieved in
the IPsec SAs that the I2NSF Controller configures in the NSFs.
Similarly, the encryption algorithms used in the security association
between I2NSF Controller and the NSF MUST have, at least, the same
strength (minimum strength of a 128-bit key) as the algorithms used
to establish the IPsec SAs.
8.3. YANG modules
The modules specified in this document define 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) [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 these YANG modules 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:
For the IKE case (ietf-i2nsf-ike):
/ipsec-ike: The entire container in this module is sensitive to
write operations. An attacker may add/modify the credentials
to be used for the authentication (e.g., to impersonate a NSF),
Marin-Lopez, et al. Expires September 26, 2021 [Page 73]
Internet-Draft SDN-based IPsec Flow Protection March 2021
the trust root (e.g., changing the trusted CA certificates),
the cryptographic algorithms (allowing a downgrading attack),
the IPsec policies (e.g., by allowing leaking of data traffic
by changing to an allow policy), and in general changing the
IKE SA conditions and credentials between any NSF.
For the IKE-less case (ietf-i2nsf-ikeless):
/ipsec-ikeless: The entire container in this module is
sensitive to write operations. An attacker may add/modify/
delete any IPsec policies (e.g., by allowing leaking of data
traffic by changing to a allow policy) in the /ipsec-ikeless/
spd container, and add/modify/delete any IPsec SAs between two
NSF by means of /ipsec-ikeless/sad container and, in general,
changing any IPsec SAs and IPsec policies between any NSF.
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:
For the IKE case (ietf-i2nsf-ike):
/ipsec-ike/pad: This container includes sensitive information
to read operations. This information MUST NOT be returned to a
client. For example, cryptographic material configured in the
NSFs (peer-authentication/pre-shared/secret and peer-
authentication/digital-signature/private-key) are already
protected by the NACM extension "default-deny-all" in this
document.
For the IKE-less case (ietf-i2nsf-ikeless):
/ipsec-ikeless/sad/sad-entry/ipsec-sa-config/esp-sa: This
container includes symmetric keys for the IPsec SAs. For
example, encryption/key contains an ESP encryption key value
and encryption/iv contains an initialization vector value.
Similarly, integrity/key has an ESP integrity key value. Those
values MUST NOT be read by anyone and are protected by the NACM
extension "default-deny-all" in this document.
9. Acknowledgements
Authors want to thank Paul Wouters, Valery Smyslov,Sowmini Varadhan,
David Carrel, Yoav Nir, Tero Kivinen, Martin Bjorklund, Graham
Bartlett, Sandeep Kampati, Linda Dunbar, Mohit Sethi, Martin
Bjorklund, Tom Petch, Christian Hopps, Rob Wilton, Carlos J.
Marin-Lopez, et al. Expires September 26, 2021 [Page 74]
Internet-Draft SDN-based IPsec Flow Protection March 2021
Bernardos, Alejandro Perez-Mendez, Alejandro Abad-Carrascosa, Ignacio
Martinez, Ruben Ricart, and all IESG members that have reviewed this
document for their valuable comments.
10. References
10.1. Normative References
[IANA-Method-Type]
Internet Assigned Numbers Authority (IANA), "Method Type",
April 2020, <https://www.iana.org/assignments/eap-numbers/
eap-numbers.xhtml#eap-numbers-4>.
[IANA-Protocols-Number]
Internet Assigned Numbers Authority (IANA), "Protocol
Numbers", January 2020, <https://www.iana.org/assignments/
protocol-numbers/protocol-numbers.xhtml>.
[IKEv2-Auth-Method]
Internet Assigned Numbers Authority (IANA), "Internet Key
Exchange Version 2 (IKEv2) Parameters - IKEv2
Authentication Method", August 2020,
<https://www.iana.org/assignments/ikev2-parameters/
ikev2-parameters.xhtml#ikev2-parameters-12>.
[IKEv2-Parameters]
Internet Assigned Numbers Authority (IANA), "Internet Key
Exchange Version 2 (IKEv2) Parameters", August 2020,
<https://www.iana.org/assignments/ikev2-parameters/
ikev2-parameters.xhtml>.
[IKEv2-Transform-Type-1]
Internet Assigned Numbers Authority (IANA), "Internet Key
Exchange Version 2 (IKEv2) Parameters - Transform Type
Values - Transform Type 1 - Encryption Algorithm Transform
IDs", August 2020, <https://www.iana.org/assignments/
ikev2-parameters/ikev2-parameters.xhtml#ikev2-parameters-
5>.
[IKEv2-Transform-Type-3]
Internet Assigned Numbers Authority (IANA), "Internet Key
Exchange Version 2 (IKEv2) Parameters - Transform Type
Values - Transform Type 3 - Integrity Algorithm Transform
IDs", August 2020, <https://www.iana.org/assignments/
ikev2-parameters/ikev2-parameters.xhtml#ikev2-parameters-
7>.
Marin-Lopez, et al. Expires September 26, 2021 [Page 75]
Internet-Draft SDN-based IPsec Flow Protection March 2021
[IKEv2-Transform-Type-4]
Internet Assigned Numbers Authority (IANA), "Internet Key
Exchange Version 2 (IKEv2) Parameters - Transform Type
Values - Transform Type 4 - Diffie-Hellman Group Transform
IDs", August 2020, <https://www.iana.org/assignments/
ikev2-parameters/ikev2-parameters.xhtml#ikev2-parameters-
8>.
[ITU-T.X.690]
"Recommendation ITU-T X.690", August 2015.
[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>.
[RFC2247] Kille, S., Wahl, M., Grimstad, A., Huber, R., and S.
Sataluri, "Using Domains in LDAP/X.500 Distinguished
Names", RFC 2247, DOI 10.17487/RFC2247, January 1998,
<https://www.rfc-editor.org/info/rfc2247>.
[RFC3947] Kivinen, T., Swander, B., Huttunen, A., and V. Volpe,
"Negotiation of NAT-Traversal in the IKE", RFC 3947,
DOI 10.17487/RFC3947, January 2005,
<https://www.rfc-editor.org/info/rfc3947>.
[RFC3948] Huttunen, A., Swander, B., Volpe, V., DiBurro, L., and M.
Stenberg, "UDP Encapsulation of IPsec ESP Packets",
RFC 3948, DOI 10.17487/RFC3948, January 2005,
<https://www.rfc-editor.org/info/rfc3948>.
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
December 2005, <https://www.rfc-editor.org/info/rfc4301>.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)",
RFC 4303, DOI 10.17487/RFC4303, December 2005,
<https://www.rfc-editor.org/info/rfc4303>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>.
[RFC5322] Resnick, P., Ed., "Internet Message Format", RFC 5322,
DOI 10.17487/RFC5322, October 2008,
<https://www.rfc-editor.org/info/rfc5322>.
Marin-Lopez, et al. Expires September 26, 2021 [Page 76]
Internet-Draft SDN-based IPsec Flow Protection March 2021
[RFC5915] Turner, S. and D. Brown, "Elliptic Curve Private Key
Structure", RFC 5915, DOI 10.17487/RFC5915, June 2010,
<https://www.rfc-editor.org/info/rfc5915>.
[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>.
[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <https://www.rfc-editor.org/info/rfc7296>.
[RFC7383] Smyslov, V., "Internet Key Exchange Protocol Version 2
(IKEv2) Message Fragmentation", RFC 7383,
DOI 10.17487/RFC7383, November 2014,
<https://www.rfc-editor.org/info/rfc7383>.
[RFC7427] Kivinen, T. and J. Snyder, "Signature Authentication in
the Internet Key Exchange Version 2 (IKEv2)", RFC 7427,
DOI 10.17487/RFC7427, January 2015,
<https://www.rfc-editor.org/info/rfc7427>.
[RFC7619] Smyslov, V. and P. Wouters, "The NULL Authentication
Method in the Internet Key Exchange Protocol Version 2
(IKEv2)", RFC 7619, DOI 10.17487/RFC7619, August 2015,
<https://www.rfc-editor.org/info/rfc7619>.
[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>.
Marin-Lopez, et al. Expires September 26, 2021 [Page 77]
Internet-Draft SDN-based IPsec Flow Protection March 2021
[RFC8017] Moriarty, K., Ed., Kaliski, B., Jonsson, J., and A. Rusch,
"PKCS #1: RSA Cryptography Specifications Version 2.2",
RFC 8017, DOI 10.17487/RFC8017, November 2016,
<https://www.rfc-editor.org/info/rfc8017>.
[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>.
[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>.
[RFC8221] Wouters, P., Migault, D., Mattsson, J., Nir, Y., and T.
Kivinen, "Cryptographic Algorithm Implementation
Requirements and Usage Guidance for Encapsulating Security
Payload (ESP) and Authentication Header (AH)", RFC 8221,
DOI 10.17487/RFC8221, October 2017,
<https://www.rfc-editor.org/info/rfc8221>.
[RFC8229] Pauly, T., Touati, S., and R. Mantha, "TCP Encapsulation
of IKE and IPsec Packets", RFC 8229, DOI 10.17487/RFC8229,
August 2017, <https://www.rfc-editor.org/info/rfc8229>.
[RFC8247] Nir, Y., Kivinen, T., Wouters, P., and D. Migault,
"Algorithm Implementation Requirements and Usage Guidance
for the Internet Key Exchange Protocol Version 2 (IKEv2)",
RFC 8247, DOI 10.17487/RFC8247, September 2017,
<https://www.rfc-editor.org/info/rfc8247>.
[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>.
Marin-Lopez, et al. Expires September 26, 2021 [Page 78]
Internet-Draft SDN-based IPsec Flow Protection March 2021
10.2. Informative References
[I-D.carrel-ipsecme-controller-ike]
Carrel, D. and B. Weiss, "IPsec Key Exchange using a
Controller", draft-carrel-ipsecme-controller-ike-01 (work
in progress), March 2019.
[I-D.tran-ipsecme-yang]
Tran, K., Wang, H., Nagaraj, V., and X. Chen, "Yang Data
Model for Internet Protocol Security (IPsec)", draft-tran-
ipsecme-yang-01 (work in progress), June 2015.
[ITU-T.Y.3300]
"Recommendation ITU-T Y.3300", June 2014,
<https://www.itu.int/rec/T-REC-Y.3300/en>.
[libreswan]
The Libreswan Project, "Libreswan VPN software", September
2020, <https://libreswan.org/>.
[netconf-vpn]
Stefan Wallin, "Tutorial: NETCONF and YANG", January 2014,
<https://ripe68.ripe.net/presentations/181-NETCONF-YANG-
tutorial-43.pdf>.
[ONF-OpenFlow]
ONF, "OpenFlow Switch Specification (Version 1.4.0)",
October 2013, <https://www.opennetworking.org/wp-
content/uploads/2014/10/openflow-spec-v1.4.0.pdf >.
[ONF-SDN-Architecture]
"SDN Architecture", June 2014,
<https://www.opennetworking.org/wp-
content/uploads/2013/02/TR_SDN_ARCH_1.0_06062014.pdf >.
[RFC2367] McDonald, D., Metz, C., and B. Phan, "PF_KEY Key
Management API, Version 2", RFC 2367,
DOI 10.17487/RFC2367, July 1998,
<https://www.rfc-editor.org/info/rfc2367>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>.
[RFC6040] Briscoe, B., "Tunnelling of Explicit Congestion
Notification", RFC 6040, DOI 10.17487/RFC6040, November
2010, <https://www.rfc-editor.org/info/rfc6040>.
Marin-Lopez, et al. Expires September 26, 2021 [Page 79]
Internet-Draft SDN-based IPsec Flow Protection March 2021
[RFC6071] Frankel, S. and S. Krishnan, "IP Security (IPsec) and
Internet Key Exchange (IKE) Document Roadmap", RFC 6071,
DOI 10.17487/RFC6071, February 2011,
<https://www.rfc-editor.org/info/rfc6071>.
[RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme,
"IPv6 Flow Label Specification", RFC 6437,
DOI 10.17487/RFC6437, November 2011,
<https://www.rfc-editor.org/info/rfc6437>.
[RFC7149] Boucadair, M. and C. Jacquenet, "Software-Defined
Networking: A Perspective from within a Service Provider
Environment", RFC 7149, DOI 10.17487/RFC7149, March 2014,
<https://www.rfc-editor.org/info/rfc7149>.
[RFC7426] Haleplidis, E., Ed., Pentikousis, K., Ed., Denazis, S.,
Hadi Salim, J., Meyer, D., and O. Koufopavlou, "Software-
Defined Networking (SDN): Layers and Architecture
Terminology", RFC 7426, DOI 10.17487/RFC7426, January
2015, <https://www.rfc-editor.org/info/rfc7426>.
[RFC8192] Hares, S., Lopez, D., Zarny, M., Jacquenet, C., Kumar, R.,
and J. Jeong, "Interface to Network Security Functions
(I2NSF): Problem Statement and Use Cases", RFC 8192,
DOI 10.17487/RFC8192, July 2017,
<https://www.rfc-editor.org/info/rfc8192>.
[RFC8329] Lopez, D., Lopez, E., Dunbar, L., Strassner, J., and R.
Kumar, "Framework for Interface to Network Security
Functions", RFC 8329, DOI 10.17487/RFC8329, February 2018,
<https://www.rfc-editor.org/info/rfc8329>.
[SDNSecServ]
Scott-Hayward, S., O'Callaghan, G., and P. Sezer, "SDN
Security: A Survey. IEEE SDN for Future Networks and
Services (SDN4FNS), Trento, 2013, pp. 1-7, doi: 10.1109/
SDN4FNS.2013.6702553.", 2013.
[SDNSecurity]
Kreutz, D., Ramos, F., and P. Verissimo, "Towards secure
and dependable software-defined networks. HotSDN 2013 -
Proceedings of the 2013 ACM SIGCOMM Workshop on Hot Topics
in Software Defined Networking. 55-60.
10.1145/2491185.2491199.", 2013.
[strongswan]
CESNET, "StrongSwan: the OpenSource IPsec-based VPN
Solution", September 2020, <https://www.strongswan.org/>.
Marin-Lopez, et al. Expires September 26, 2021 [Page 80]
Internet-Draft SDN-based IPsec Flow Protection March 2021
Appendix A. XML configuration example for IKE case (gateway-to-gateway)
This example shows a XML configuration file sent by the I2NSF
Controller to establish a IPsec SA between two NSFs (see Figure 3) in
tunnel mode (gateway-to-gateway) with ESP, authentication based on
X.509 certificates (simplified for brevity with
"base64encodedvalue==") and applying the IKE case.
+------------------+
| I2NSF Controller |
+------------------+
I2NSF NSF-Facing |
Interface |
/-----------------+---------------\
/ \
/ \
+----+ +--------+ +--------+ +----+
| h1 |--| nsf_h1 |== IPsec_ESP_Tunnel_mode == | nsf_h2 |--| h2 |
+----+ +--------+ +--------+ +----+
:1 :100 :200 :1
(2001:db8:1:/64) (2001:db8:123:/64) (2001:db8:2:/64)
Figure 3: IKE case, tunnel mode , X.509 certificate authentication.
<ipsec-ike xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-ike"
xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0">
<pad>
<pad-entry>
<name>nsf_h1_pad</name>
<ipv6-address>2001:db8:123::100</ipv6-address>
<peer-authentication>
<auth-method>digital-signature</auth-method>
<digital-signature>
<cert-data>base64encodedvalue==</cert-data>
<private-key>base64encodedvalue==</private-key>
<ca-data>base64encodedvalue==</ca-data>
</digital-signature>
</peer-authentication>
</pad-entry>
<pad-entry>
<name>nsf_h2_pad</name>
<ipv6-address>2001:db8:123::200</ipv6-address>
<auth-protocol>ikev2</auth-protocol>
<peer-authentication>
Marin-Lopez, et al. Expires September 26, 2021 [Page 81]
Internet-Draft SDN-based IPsec Flow Protection March 2021
<auth-method>digital-signature</auth-method>
<digital-signature>
<!-- RSA Digital Signature -->
<ds-algorithm>1</ds-algorithm>
<cert-data>base64encodedvalue==</cert-data>
<ca-data>base64encodedvalue==</ca-data>
</digital-signature>
</peer-authentication>
</pad-entry>
</pad>
<conn-entry>
<name>nsf_h1-nsf_h2</name>
<autostartup>start</autostartup>
<version>ikev2</version>
<initial-contact>false</initial-contact>
<fragmentation><enable>false</enable></fragmentation>
<ike-sa-lifetime-soft>
<rekey-time>60</rekey-time>
<reauth-time>120</reauth-time>
</ike-sa-lifetime-soft>
<ike-sa-lifetime-hard>
<over-time>3600</over-time>
</ike-sa-lifetime-hard>
<!--AUTH_HMAC_SHA2_512_256-->
<ike-sa-intr-alg>14</ike-sa-intr-alg>
<!--ENCR_AES_CBC - 128 bits-->
<ike-sa-encr-alg>
<id>1</id>
</ike-sa-encr-alg>
<!--8192-bit MODP Group-->
<dh-group>18</dh-group>
<half-open-ike-sa-timer>30</half-open-ike-sa-timer>
<half-open-ike-sa-cookie-threshold>
15
</half-open-ike-sa-cookie-threshold>
<local>
<local-pad-entry-name>nsf_h1_pad</local-pad-entry-name>
</local>
<remote>
<remote-pad-entry-name>nsf_h2_pad</remote-pad-entry-name>
</remote>
<spd>
<spd-entry>
<name>nsf_h1-nsf_h2</name>
<ipsec-policy-config>
<anti-replay-window-size>64</anti-replay-window-size>
<traffic-selector>
<local-prefix>2001:db8:1::0/64</local-prefix>
Marin-Lopez, et al. Expires September 26, 2021 [Page 82]
Internet-Draft SDN-based IPsec Flow Protection March 2021
<remote-prefix>2001:db8:2::0/64</remote-prefix>
<inner-protocol>any</inner-protocol>
</traffic-selector>
<processing-info>
<action>protect</action>
<ipsec-sa-cfg>
<pfp-flag>false</pfp-flag>
<ext-seq-num>true</ext-seq-num>
<seq-overflow>false</seq-overflow>
<stateful-frag-check>false</stateful-frag-check>
<mode>tunnel</mode>
<protocol-parameters>esp</protocol-parameters>
<esp-algorithms>
<!-- AUTH_HMAC_SHA1_96 -->
<integrity>2</integrity>
<encryption>
<!-- ENCR_AES_CBC -->
<id>1</id>
<algorithm-type>12</algorithm-type>
<key-length>128</key-length>
</encryption>
<encryption>
<!-- ENCR_3DES-->
<id>2</id>
<algorithm-type>3</algorithm-type>
</encryption>
<tfc-pad>false</tfc-pad>
</esp-algorithms>
<tunnel>
<local>2001:db8:123::100</local>
<remote>2001:db8:123::200</remote>
<df-bit>clear</df-bit>
<bypass-dscp>true</bypass-dscp>
</tunnel>
</ipsec-sa-cfg>
</processing-info>
</ipsec-policy-config>
</spd-entry>
</spd>
<child-sa-info>
<!--8192-bit MODP Group -->
<fs-groups>18</fs-groups>
<child-sa-lifetime-soft>
<bytes>1000000</bytes>
<packets>1000</packets>
<time>30</time>
<idle>60</idle>
<action>replace</action>
Marin-Lopez, et al. Expires September 26, 2021 [Page 83]
Internet-Draft SDN-based IPsec Flow Protection March 2021
</child-sa-lifetime-soft>
<child-sa-lifetime-hard>
<bytes>2000000</bytes>
<packets>2000</packets>
<time>60</time>
<idle>120</idle>
</child-sa-lifetime-hard>
</child-sa-info>
</conn-entry>
</ipsec-ike>
Appendix B. XML configuration example for IKE-less case (host-to-host)
This example shows a XML configuration file sent by the I2NSF
Controller to establish a IPsec SA between two NSFs (see Figure 4) in
transport mode (host-to-host) with ESP in the IKE-less case.
+------------------+
| I2NSF Controller |
+------------------+
I2NSF NSF-Facing |
Interface |
/--------------------+-------------------\
/ \
/ \
+--------+ +--------+
| nsf_h1 |===== IPsec_ESP_Transport_mode =====| nsf_h2 |
+--------+ +--------+
:100 (2001:db8:123:/64) :200
Figure 4: IKE-less case, transport mode.
<ipsec-ikeless
xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikeless"
xmlns:nc="urn:ietf:params:xml:ns:netconf:base:1.0">
<spd>
<spd-entry>
<name>
in/trans/2001:db8:123::200/2001:db8:123::100
</name>
<direction>inbound</direction>
<reqid>1</reqid>
<ipsec-policy-config>
Marin-Lopez, et al. Expires September 26, 2021 [Page 84]
Internet-Draft SDN-based IPsec Flow Protection March 2021
<traffic-selector>
<local-prefix>2001:db8:123::200/128</local-prefix>
<remote-prefix>2001:db8:123::100/128</remote-prefix>
<inner-protocol>any</inner-protocol>
</traffic-selector>
<processing-info>
<action>protect</action>
<ipsec-sa-cfg>
<ext-seq-num>true</ext-seq-num>
<seq-overflow>false</seq-overflow>
<mode>transport</mode>
<protocol-parameters>esp</protocol-parameters>
<esp-algorithms>
<!--AUTH_HMAC_SHA1_96-->
<integrity>2</integrity>
<!--ENCR_AES_CBC -->
<encryption>
<id>1</id>
<algorithm-type>12</algorithm-type>
<key-length>128</key-length>
</encryption>
<encryption>
<id>2</id>
<algorithm-type>3</algorithm-type>
</encryption>
</esp-algorithms>
</ipsec-sa-cfg>
</processing-info>
</ipsec-policy-config>
</spd-entry>
<spd-entry>
<name>out/trans/2001:db8:123::100/2001:db8:123::200</name>
<direction>outbound</direction>
<reqid>1</reqid>
<ipsec-policy-config>
<traffic-selector>
<local-prefix>2001:db8:123::100/128</local-prefix>
<remote-prefix>2001:db8:123::200/128</remote-prefix>
<inner-protocol>any</inner-protocol>
</traffic-selector>
<processing-info>
<action>protect</action>
<ipsec-sa-cfg>
<ext-seq-num>true</ext-seq-num>
<seq-overflow>false</seq-overflow>
<mode>transport</mode>
<protocol-parameters>esp</protocol-parameters>
<esp-algorithms>
Marin-Lopez, et al. Expires September 26, 2021 [Page 85]
Internet-Draft SDN-based IPsec Flow Protection March 2021
<!-- AUTH_HMAC_SHA1_96 -->
<integrity>2</integrity>
<!-- ENCR_AES_CBC -->
<encryption>
<id>1</id>
<algorithm-type>12</algorithm-type>
<key-length>128</key-length>
</encryption>
<encryption>
<id>2</id>
<algorithm-type>3</algorithm-type>
</encryption>
</esp-algorithms>
</ipsec-sa-cfg>
</processing-info>
</ipsec-policy-config>
</spd-entry>
</spd>
<sad>
<sad-entry>
<name>out/trans/2001:db8:123::100/2001:db8:123::200</name>
<reqid>1</reqid>
<ipsec-sa-config>
<spi>34501</spi>
<ext-seq-num>true</ext-seq-num>
<seq-overflow>false</seq-overflow>
<anti-replay-window-size>64</anti-replay-window-size>
<traffic-selector>
<local-prefix>2001:db8:123::100/128</local-prefix>
<remote-prefix>2001:db8:123::200/128</remote-prefix>
<inner-protocol>any</inner-protocol>
</traffic-selector>
<protocol-parameters>esp</protocol-parameters>
<mode>transport</mode>
<esp-sa>
<encryption>
<!-- //ENCR_AES_CBC -->
<encryption-algorithm>12</encryption-algorithm>
<key>01:23:45:67:89:AB:CE:DF</key>
<iv>01:23:45:67:89:AB:CE:DF</iv>
</encryption>
<integrity>
<!-- //AUTH_HMAC_SHA1_96 -->
<integrity-algorithm>2</integrity-algorithm>
<key>01:23:45:67:89:AB:CE:DF</key>
</integrity>
</esp-sa>
</ipsec-sa-config>
Marin-Lopez, et al. Expires September 26, 2021 [Page 86]
Internet-Draft SDN-based IPsec Flow Protection March 2021
</sad-entry>
<sad-entry>
<name>in/trans/2001:db8:123::200/2001:db8:123::100</name>
<reqid>1</reqid>
<ipsec-sa-config>
<spi>34502</spi>
<ext-seq-num>true</ext-seq-num>
<seq-overflow>false</seq-overflow>
<anti-replay-window-size>64</anti-replay-window-size>
<traffic-selector>
<local-prefix>2001:db8:123::200/128</local-prefix>
<remote-prefix>2001:db8:123::100/128</remote-prefix>
<inner-protocol>any</inner-protocol>
</traffic-selector>
<protocol-parameters>esp</protocol-parameters>
<mode>transport</mode>
<esp-sa>
<encryption>
<!-- //ENCR_AES_CBC -->
<encryption-algorithm>12</encryption-algorithm>
<key>01:23:45:67:89:AB:CE:DF</key>
<iv>01:23:45:67:89:AB:CE:DF</iv>
</encryption>
<integrity>
<!-- //AUTH_HMAC_SHA1_96 -->
<integrity-algorithm>2</integrity-algorithm>
<key>01:23:45:67:89:AB:CE:DF</key>
</integrity>
</esp-sa>
<sa-lifetime-hard>
<bytes>2000000</bytes>
<packets>2000</packets>
<time>60</time>
<idle>120</idle>
</sa-lifetime-hard>
<sa-lifetime-soft>
<bytes>1000000</bytes>
<packets>1000</packets>
<time>30</time>
<idle>60</idle>
<action>replace</action>
</sa-lifetime-soft>
</ipsec-sa-config>
</sad-entry>
</sad>
</ipsec-ikeless>
Marin-Lopez, et al. Expires September 26, 2021 [Page 87]
Internet-Draft SDN-based IPsec Flow Protection March 2021
Appendix C. XML notification examples
In the following, several XML files are shown to illustrate different
types of notifications defined in the IKE-less YANG model, which are
sent by the NSF to the I2NSF Controller. The notifications happen in
the IKE-less case.
<sadb-expire xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikeless">
<ipsec-sa-name>in/trans/2001:db8:123::200/2001:db8:123::100
</ipsec-sa-name>
<soft-lifetime-expire>true</soft-lifetime-expire>
<lifetime-current>
<bytes>1000000</bytes>
<packets>1000</packets>
<time>30</time>
<idle>60</idle>
</lifetime-current>
</sadb-expire>
Figure 5: Example of sadb-expire notification.
<sadb-acquire xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikeless">
<ipsec-policy-name>in/trans/2001:db8:123::200/2001:db8:123::100
</ipsec-policy-name>
<traffic-selector>
<local-prefix>2001:db8:123::200/128</local-prefix>
<remote-prefix>2001:db8:123::100/128</remote-prefix>
<inner-protocol>any</inner-protocol>
<local-ports>
<start>0</start>
<end>0</end>
</local-ports>
<remote-ports>
<start>0</start>
<end>0</end>
</remote-ports>
</traffic-selector>
</sadb-acquire>
Figure 6: Example of sadb-acquire notification.
Marin-Lopez, et al. Expires September 26, 2021 [Page 88]
Internet-Draft SDN-based IPsec Flow Protection March 2021
<sadb-seq-overflow
xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikeless">
<ipsec-sa-name>in/trans/2001:db8:123::200/2001:db8:123::100
</ipsec-sa-name>
</sadb-seq-overflow>
Figure 7: Example of sadb-seq-overflow notification.
<sadb-bad-spi
xmlns="urn:ietf:params:xml:ns:yang:ietf-i2nsf-ikeless">
<spi>666</spi>
</sadb-bad-spi>
Figure 8: Example of sadb-bad-spi notification.
Appendix D. Operational use cases examples
D.1. Example of IPsec SA establishment
This appendix exemplifies the applicability of IKE case and IKE-less
case to traditional IPsec configurations, that is, host-to-host and
gateway-to-gateway. The following examples assume the existence of
two NSFs needing to establish an end-to-end IPsec SA to protect their
communications. Both NSFs could be two hosts that exchange traffic
(host-to-host) or gateways (gateway-to-gateway), for example, within
an enterprise that needs to protect the traffic between the networks
of two branch offices.
Applicability of these configurations appear in current and new
networking scenarios. For example, SD-WAN technologies are providing
dynamic and on-demand VPN connections between branch offices, or
between branches and SaaS cloud services. Besides, IaaS services
providing virtualization environments are deployments that often rely
on IPsec to provide secure channels between virtual instances (host-
to-host) and providing VPN solutions for virtualized networks
(gateway-to-gateway).
As can be observed in the following, the I2NSF-based IPsec management
system (for IKE and IKE-less cases), exhibits various advantages:
1. It allows to create IPsec SAs among two NSFs, based only on the
application of general Flow-based Protection Policies at the
I2NSF User. Thus, administrators can manage all security
associations in a centralized point with an abstracted view of
the network.
Marin-Lopez, et al. Expires September 26, 2021 [Page 89]
Internet-Draft SDN-based IPsec Flow Protection March 2021
2. Any NSF deployed in the system does not need manual
configuration, therefore allowing its deployment in an automated
manner.
D.1.1. IKE case
+----------------------------------------+
| I2NSF User (IPsec Management System) |
+----------------------------------------+
|
(1) Flow-based I2NSF Consumer-Facing
Protection Policy Interface
|
+---------|------------------------------+
| | |
| | I2NSF Controller |
| V |
| +--------------+ (2)+--------------+ |
| |Translate into|--->| NETCONF/ | |
| |IPsec Policies| | RESTCONF | |
| +--------------+ +--------------+ |
| | | |
| | | |
+--------------------------|-----|-------+
| |
I2NSF NSF-Facing Interface | |
| (3) |
|-------------------------+ +---|
V V
+----------------------+ +----------------------+
| NSF A | | NSF B |
| IKEv2/IPsec(SPD/PAD) | | IKEv2/IPsec(SPD/PAD) |
+----------------------+ +----------------------+
Figure 9: Host-to-host / gateway-to-gateway for the IKE case.
Figure 9 describes the application of the IKE case when a data packet
needs to be protected in the path between the NSF A and NSF B:
1. The I2NSF User defines a general flow-based protection policy
(e.g., protect data traffic between NSF A and B). The I2NSF
Controller looks for the NSFs involved (NSF A and NSF B).
2. The I2NSF Controller generates IKEv2 credentials for them and
translates the policies into SPD and PAD entries.
Marin-Lopez, et al. Expires September 26, 2021 [Page 90]
Internet-Draft SDN-based IPsec Flow Protection March 2021
3. The I2NSF Controller inserts an IKEv2 configuration that includes
the SPD and PAD entries in both NSF A and NSF B. If some of
operations with NSF A and NSF B fail the I2NSF Controller will
stop the process and perform a rollback operation by deleting any
IKEv2, SPD and PAD configuration that had been successfully
installed in NSF A or B.
If the previous steps are successful, the flow is protected by means
of the IPsec SA established with IKEv2 between NSF A and NSF B.
D.1.2. IKE-less case
+----------------------------------------+
| I2NSF User (IPsec Management System) |
+----------------------------------------+
|
(1) Flow-based I2NSF Consumer-Facing
Protection Policy Interface
|
+---------|------------------------------+
| | |
| | I2NSF Controller |
| V |
| +--------------+ (2) +--------------+ |
| |Translate into|---->| NETCONF/ | |
| |IPsec Policies| | RESTCONF | |
| +--------------+ +--------------+ |
| | | |
+-------------------------|-----|--------+
| |
I2NSF NSF-Facing Interface | |
| (3) |
|----------------------+ +--|
V V
+----------------+ +----------------+
| NSF A | | NSF B |
| IPsec(SPD/SAD) | | IPsec(SPD/SAD) |
+----------------+ +----------------+
Figure 10: Host-to-host / gateway-to-gateway for IKE-less case.
Figure 10 describes the application of the IKE-less case when a data
packet needs to be protected in the path between the NSF A and NSF B:
1. The I2NSF User establishes a general Flow-based Protection Policy
and the I2NSF Controller looks for the involved NSFs.
Marin-Lopez, et al. Expires September 26, 2021 [Page 91]
Internet-Draft SDN-based IPsec Flow Protection March 2021
2. The I2NSF Controller translates the flow-based security policies
into IPsec SPD and SAD entries.
3. The I2NSF Controller inserts these entries in both NSF A and NSF
B IPsec databases (i.e., SPD and SAD). The following text
describes how this would happen:
* The I2NSF Controller chooses two random values as SPIs: for
example, SPIa1 for the inbound IPsec SA in the NSF A and SPIb1
for the inbound IPsec SA in NSF B. The value of the SPIa1
MUST NOT be the same as any inbound SPI in A. In the same
way, the value of the SPIb1 MUST NOT be the same as any
inbound SPI in B. Moreover, the SPIa1 MUST be used in B for
the outbound IPsec SA to A, while SPIb1 MUST be used in A for
the outbound IPsec SA to B. It also generates fresh
cryptographic material for the new inbound/outbound IPsec SAs
and their parameters.
* After that, the I2NSF Controller sends simultaneously the new
inbound IPsec SA with SPIa1 and new outbound IPsec SA with
SPIb1 to NSF A; and the new inbound IPsec SA with SPIb1 and
new outbound IPsec SA with SPIa1 to B, together with the
corresponding IPsec policies.
* Once the I2NSF Controller receives confirmation from NSF A and
NSF B, it knows that the IPsec SAs are correctly installed and
ready.
Other alternative to this operation is: the I2NSF Controller
sends first the IPsec policies and new inbound IPsec SAs to A and
B and, once it obtains a successful confirmation of these
operations from NSF A and NSF B, it proceeds with installing the
new outbound IPsec SAs. Even though this procedure may increase
the latency to complete the process, no traffic is sent over the
network until the IPsec SAs are completely operative. In any
case other alternatives MAY be possible to implement step 3.
4. If some of the operations described above fail (e.g., the NSF A
reports an error when the I2NSF Controller is trying to install
the SPD entry, the new inbound or outbound IPsec SAs) the I2NSF
Controller MUST perform rollback operations by deleting any new
inbound or outbound IPsec SA and SPD entry that had been
successfully installed in any of the NSFs (e.g., NSF B) and stop
the process. Note that the I2NSF Controller MAY retry several
times before giving up.
5. Otherwise, if the steps 1 to 3 are successful, the flow between
NSF A and NSF B is protected by means of the IPsec SAs
Marin-Lopez, et al. Expires September 26, 2021 [Page 92]
Internet-Draft SDN-based IPsec Flow Protection March 2021
established by the I2NSF Controller. It is worth mentioning that
the I2NSF Controller associates a lifetime to the new IPsec SAs.
When this lifetime expires, the NSF will send a sadb-expire
notification to the I2NSF Controller in order to start the
rekeying process.
Instead of installing IPsec policies (in the SPD) and IPsec SAs (in
the SAD) in step 3 (proactive mode), it is also possible that the
I2NSF Controller only installs the SPD entries in step 3 (reactive
mode). In such a case, when a data packet requires to be protected
with IPsec, the NSF that saw first the data packet will send a sadb-
acquire notification that informs the I2NSF Controller that needs SAD
entries with the IPsec SAs to process the data packet. Again, if
some of the operations installing the new inbound/outbound IPsec SAs
fail, the I2NSF Controller stops the process and performs a rollback
operation by deleting any new inbound/outbound SAs that had been
successfully installed.
D.2. Example of the rekeying process in IKE-less case
To explain an example of the rekeying process between two IPsec NSFs
A and B, let assume that SPIa1 identifies the inbound IPsec SA in A,
and SPIb1 the inbound IPsec SA in B. The rekeying process will take
the following steps:
1. The I2NSF Controller chooses two random values as SPI for the new
inbound IPsec SAs: for example, SPIa2 for the inbound IPsec SA in
A and SPIb2 for the inbound IPsec SA in B. The value of the
SPIa1 MUST NOT be the same as any inbound SPI in A. In the same
way, the value of the SPIb1 MUST NOT be the same as any inbound
SPI in B. Then, the I2NSF Controller creates an inbound IPsec SA
with SPIa2 in A and another inbound IPsec SA in B with SPIb2. It
can send this information simultaneously to A and B.
2. Once the I2NSF Controller receives confirmation from A and B, the
controller knows that the inbound IPsec SAs are correctly
installed. Then it proceeds to send in parallel to A and B, the
outbound IPsec SAs: the outbound IPsec SA to A with SPIb2, and
the outbound IPsec SA to B with SPIa2. At this point the new
IPsec SAs are ready.
3. Once the I2NSF Controller receives confirmation from A and B that
the outbound IPsec SAs have been installed, the I2NSF Controller,
in parallel, deletes the old IPsec SAs from A (inbound SPIa1 and
outbound SPIb1) and B (outbound SPIa1 and inbound SPIb1).
If some of the operations in step 1 fail (e.g., the NSF A reports an
error when the I2NSF Controller is trying to install a new inbound
Marin-Lopez, et al. Expires September 26, 2021 [Page 93]
Internet-Draft SDN-based IPsec Flow Protection March 2021
IPsec SA) the I2NSF Controller MUST perform rollback operations by
removing any new inbound SA that had been successfully installed
during step 1.
If step 1 is successful but some of the operations in step 2 fail
(e.g., the NSF A reports an error when the I2NSF Controller is trying
to install the new outbound IPsec SA), the I2NSF Controller MUST
perform a rollback operation by deleting any new outbound SA that had
been successfully installed during step 2 and by deleting the inbound
SAs created in step 1, in that order.
If the steps 1 and 2 are successful but the step 3 fails, the I2NSF
Controller will avoid any rollback of the operations carried out in
step 1 and step 2 since new and valid IPsec SAs were created and are
functional. The I2NSF Controller MAY reattempt to remove the old
inbound and outbound IPsec SAs in NSF A and NSF B several times until
it receives a success or it gives up. In the last case, the old
IPsec SAs will be removed when their corresponding hard lifetime is
reached.
D.3. Example of managing NSF state loss in IKE-less case
In the IKE-less case, if the I2NSF Controller detects that a NSF has
lost the IPsec state, it could follow the next steps:
1. The I2NSF Controller SHOULD delete the old IPsec SAs on the non-
failed nodes, established with the failed node. This prevents
the non-failed nodes from leaking plaintext.
2. If the affected node restarts, the I2NSF Controller configures
the new inbound IPsec SAs between the affected node and all the
nodes it was talking to.
3. After these inbound IPsec SAs have been established, the I2NSF
Controller configures the outbound IPsec SAs in parallel.
Step 2 and step 3 can be performed at the same time at the cost of a
potential packet loss. If this is not critical then it is an
optimization since the number of exchanges between I2NSF Controller
and NSFs is lower.
Authors' Addresses
Marin-Lopez, et al. Expires September 26, 2021 [Page 94]
Internet-Draft SDN-based IPsec Flow Protection March 2021
Rafa Marin-Lopez
University of Murcia
Campus de Espinardo S/N, Faculty of Computer Science
Murcia 30100
Spain
Phone: +34 868 88 85 01
EMail: rafa@um.es
Gabriel Lopez-Millan
University of Murcia
Campus de Espinardo S/N, Faculty of Computer Science
Murcia 30100
Spain
Phone: +34 868 88 85 04
EMail: gabilm@um.es
Fernando Pereniguez-Garcia
University Defense Center
Spanish Air Force Academy, MDE-UPCT
San Javier (Murcia) 30720
Spain
Phone: +34 968 18 99 46
EMail: fernando.pereniguez@cud.upct.es
Marin-Lopez, et al. Expires September 26, 2021 [Page 95]