I2NSF R. Marin-Lopez Internet-Draft G. Lopez-Millan Intended status: Standards Track University of Murcia Expires: February 6, 2020 F. Pereniguez-Garcia University Defense Center August 5, 2019 Software-Defined Networking (SDN)-based IPsec Flow Protection draft-ietf-i2nsf-sdn-ipsec-flow-protection-07 Abstract This document describes how providing IPsec-based flow protection by means of a Software-Defined Network (SDN) controller (aka. Security Controller) and establishes the requirements to support this service. It considers two main well-known scenarios in IPsec: (i) gateway-to- gateway and (ii) host-to-host. The SDN-based service described in this document allows the distribution and monitoring of IPsec information from a Security Controller to one or several flow-based Network Security Function (NSF). The NSFs implement IPsec to protect data traffic between network resources. The document focuses on the NSF Facing Interface by providing models for configuration and state data required to allow the Security Controller to configure the IPsec databases (SPD, SAD, PAD) and IKEv2 to establish Security Associations with a reduced intervention of the network administrator. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on February 6, 2020. Marin-Lopez, et al. Expires February 6, 2020 [Page 1] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 Copyright Notice Copyright (c) 2019 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 . . . . . . . . . . . . . . . . . . . . 4 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Objectives . . . . . . . . . . . . . . . . . . . . . . . . . 6 5. SDN-based IPsec management description . . . . . . . . . . . 6 5.1. IKE case: IKE/IPsec in the NSF . . . . . . . . . . . . . 6 5.1.1. Interface Requirements for IKE case . . . . . . . . . 7 5.2. IKE-less case: IPsec (no IKEv2) in the NSF. . . . . . . . 7 5.2.1. Interface Requirements for IKE-less case . . . . . . 8 5.3. IKE case vs IKE-less case . . . . . . . . . . . . . . . . 9 5.3.1. Rekeying process. . . . . . . . . . . . . . . . . . . 10 5.3.2. NSF state loss. . . . . . . . . . . . . . . . . . . . 12 5.3.3. NAT Traversal . . . . . . . . . . . . . . . . . . . . 12 5.3.4. NSF Discovery . . . . . . . . . . . . . . . . . . . . 13 6. YANG configuration data models . . . . . . . . . . . . . . . 13 6.1. IKE case model . . . . . . . . . . . . . . . . . . . . . 14 6.2. IKE-less case model . . . . . . . . . . . . . . . . . . . 17 7. Use cases examples . . . . . . . . . . . . . . . . . . . . . 20 7.1. Host-to-host or gateway-to-gateway under the same Security Controller . . . . . . . . . . . . . . . . . . . 20 7.2. Host-to-host or gateway-to-gateway under different Security Controllers . . . . . . . . . . . . . . . . . . 24 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26 9. Security Considerations . . . . . . . . . . . . . . . . . . . 27 9.1. IKE case . . . . . . . . . . . . . . . . . . . . . . . . 28 9.2. IKE-less case . . . . . . . . . . . . . . . . . . . . . . 29 9.3. YANG modules . . . . . . . . . . . . . . . . . . . . . . 29 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 31 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 31 11.1. Normative References . . . . . . . . . . . . . . . . . . 31 11.2. Informative References . . . . . . . . . . . . . . . . . 32 Marin-Lopez, et al. Expires February 6, 2020 [Page 2] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 Appendix A. Appendix A: Common YANG model for IKE and IKE-less cases . . . . . . . . . . . . . . . . . . . . . . . 35 Appendix B. Appendix B: YANG model for IKE case . . . . . . . . 48 Appendix C. Appendix C: YANG model for IKE-less case . . . . . . 67 Appendix D. Example of IKE case, tunnel mode (gateway-to- gateway) with X.509 certificate authentication. . . 77 Appendix E. Example of IKE-less case, transport mode (host-to- host). . . . . . . . . . . . . . . . . . . . . . . . 81 Appendix F. Examples of notifications. . . . . . . . . . . . . . 85 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 86 1. Introduction Software-Defined Networking (SDN) is an architecture that enables users to directly program, orchestrate, control and manage network resources through software. The SDN paradigm relocates the control of network resources to a dedicated network element, namely SDN Controller. The SDN controller (or Security Controller in the context of this document) manages and configures the distributed network resources and provides an abstracted view of the network resources to the SDN applications. The SDN application 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 are considering a centralized way of managing different security aspects. For example, Software- Defined WANs (SD-WAN), an SDN extension providing a software abstraction to create secure network overlays over traditional WAN and branch networks. SD-WAN is based on IPsec as underlying security protocol and aims to provide flexible, automated, fast deployment and on-demand security network services such as IPsec SA management from a centralized point. Therefore, with the growth of SDN-based scenarios where network resources are deployed in an autonomous manner, a mechanism to manage IPsec SAs according to the SDN architecture becomes more relevant. Thus, the SDN-based service described in this document will autonomously deal with IPsec SAs management following the SDN paradigm. IPsec architecture [RFC4301] defines clear separation between the processing to provide security services to IP packets and the key management procedures to establish the IPsec Security Associations. In this document, we define a service where the key management procedures can be carried by an external and centralized entity: the Security Controller. Marin-Lopez, et al. Expires February 6, 2020 [Page 3] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 First, this document exposes the requirements to support the protection of data flows using IPsec [RFC4301]. We have considered two general cases: 1) IKE case. The Network Security Function (NSF) implements the Internet Key Exchange (IKE) protocol and the IPsec databases: the Security Policy Database (SPD), the Security Association Database (SAD) and the Peer Authorization Database (PAD). The Security Controller is in charge of provisioning the NSF with the required information to IKE, the SPD and the PAD. 2) IKE-less case. The NSF only implements the IPsec databases (no IKE implementation). The Security Controller will provide the required parameters to create valid entries in the SPD and the SAD into the NSF. Therefore, the NSF will have only support for IPsec while automated key management functionality is moved to the Security Controller. In both cases, an interface/protocol is required to carry out this provisioning in a secure manner between the Security Controller and the NSF. In particular, IKE case requires the provision of SPD and PAD entries, the IKE credential and information related with the IKE negotiation (e.g. IKE_SA_INIT). IKE-less case requires the management of SPD and SAD entries. Based on YANG models in [netconf-vpn] and [I-D.tran-ipsecme-yang], RFC 4301 [RFC4301] and RFC 7296 [RFC7296], this document defines the required interfaces with a YANG model for configuration and state data for IKE, PAD, SPD and SAD (see Appendix A, Appendix B and Appendix C). Examples of the usage of these models can found in Appendix D, Appendix E and Appendix F. This document considers two typical scenarios to manage autonomously IPsec SAs: gateway-to-gateway and host-to-host [RFC6071]. In these cases, hosts, gateways or both may act as NSFs. Finally, it also discusses the situation where two NSFs are under the control of two different Security Controllers. The analysis of the host-to-gateway (roadwarrior) scenario is out of scope of this document. Finally, this work pays attention to the challenge "Lack of Mechanism for Dynamic Key Distribution to NSFs" defined in [RFC8192] in the particular case of the establishment and management of IPsec SAs. In fact,this I-D could be considered as a proper use case for this particular challenge in [RFC8192]. 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 RFC Marin-Lopez, et al. Expires February 6, 2020 [Page 4] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 2119 [RFC2119]. When these words appear in lower case, they have their natural language meaning. 3. Terminology This document uses the terminology described in [RFC7149], [RFC4301], [ITU-T.Y.3300], [ONF-SDN-Architecture], [ONF-OpenFlow], [ITU-T.X.1252], [ITU-T.X.800] and [I-D.ietf-i2nsf-terminology]. In addition, the following terms are defined below: o Software-Defined Networking. A set of techniques enabling to directly program, orchestrate, control, and manage network resources, which facilitates the design, delivery and operation of network services in a dynamic and scalable manner [ITU-T.Y.3300]. o Flow/Data Flow. Set of network packets sharing a set of characteristics, for example IP dst/src values or QoS parameters. o Security Controller. An entity that contains control plane functions to manage and facilitate information sharing, as well as execute security functions. In the context of this document, it provides IPsec management information. o Network Security Function (NSF). Software that provides a set of security-related services. o Flow-based NSF. A NSF that inspects network flows according to a set of policies intended for enforcing security properties. The NSFs considered in this document fall into this classification. o Flow-based Protection Policy. The set of rules defining the conditions under which a data flow MUST be protected with IPsec, and the rules that MUST be applied to the specific flow. o Internet Key Exchange (IKE) v2. Protocol to establish IPsec Security Associations (SAs). It requires information about the required authentication method (i.e. raw RSA/ECDSA keys or X.509 certificates), Diffie-Hellman (DH) groups, IPsec SAs parameters and algorithms for IKE SA negotiation, etc. o Security Policy Database (SPD). It includes information about IPsec policies direction (in, out), local and remote addresses (traffic selectors information), inbound and outboud IPsec SAs, etc. o Security Associations Database (SAD). It includes information about IPsec SAs, such as SPI, destination addresses, Marin-Lopez, et al. Expires February 6, 2020 [Page 5] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 authentication and encryption algorithms and keys to protect IP flows. o Peer Authorization Database (PAD). It provides the link between the SPD and a security association management protocol. It is used when the NSF deploys IKE implementation (IKE case). 4. Objectives o To describe the architecture for the SDN-based IPsec management, which implements a security service to allow the establishment and management of IPsec security associations from a central point, in order to protect specific data flows. o To define the interfaces required to manage and monitor the IPsec Security Associations (SA) in the NSF from a Security Controller. YANG models are defined for configuration and state data for IPsec management. 5. SDN-based IPsec management description As mentioned in Section 1, two cases are considered, depending on whether the NSF ships an IKEv2 implementation or not: IKE case and IKE-less case. 5.1. IKE case: IKE/IPsec in the NSF In this case the NSF ships an IKEv2 implementation besides the IPsec support. The Security Controller is in charge of managing and applying IPsec connection information (determining which nodes need to start an IKE/IPsec session, deriving and delivering IKE Credentials such as a pre-shared key, certificates, etc.), and applying other IKE configuration parameters (e.g. cryptographic algorithms for establishing an IKE SA) to the NSF for the IKE negotiation. With these entries, the IKEv2 implementation can operate to establish the IPsec SAs. The application (administrator) establishes the IPsec requirements and information about the end points information (through the Client Facing Interface, [RFC8192]), and the Security Controller translates these requirements into IKE, SPD and PAD entries that will be installed into the NSF (through the NSF Facing Interface). With that information, the NSF can just run IKEv2 to establish the required IPsec SA (when the data flow needs protection). Figure 1 shows the different layers and corresponding functionality. Marin-Lopez, et al. Expires February 6, 2020 [Page 6] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 +-------------------------------------------+ |IPsec Management/Orchestration Application | Client or | I2NSF Client | App Gateway +-------------------------------------------+ | Client Facing Interface +-------------------------------------------+ Vendor | Application Support | Facing<->|-------------------------------------------| Security Interface| IKE Credential,PAD and SPD entries Distr. | Controller +-------------------------------------------+ | NSF Facing Interface +-------------------------------------------+ | I2NSF Agent | |-------------------------------------------| Network | IKE | IPsec(SPD,PAD) | Security |-------------------------------------------| Function | Data Protection and Forwarding | +-------------------------------------------+ Figure 1: IKE case: IKE/IPsec in the NSF 5.1.1. Interface Requirements for IKE case SDN-based IPsec flow protection services provide dynamic and flexible management of IPsec SAs in flow-based NSFs. In order to support this capability in IKE case, the following interface requirements need to be met: o A YANG data model for IKEv2, SPD and PAD configuration data, and for IKE state data. o In scenarios where multiple Security Controllers are implicated, SDN-based IPsec management services may require a mechanism to discover which Security Controller is managing a specific NSF. Moreover, an east-west interface [RFC7426] is required to exchange IPsec-related information. For example, if two gateways need to establish an IPsec SA and both are under the control of two different controllers, then both Security Controllers need to exchange information to properly configure their own NSFs. That is, the may need to agree on whether IKEv2 authentication will be based on raw public keys, pre-shared keys, etc. In case of using pre-shared keys they will have to agree in the PSK. 5.2. IKE-less case: IPsec (no IKEv2) in the NSF. In this case, the NSF does not deploy IKEv2 and, therefore, the Security Controller has to perform the IKE security functions and Marin-Lopez, et al. Expires February 6, 2020 [Page 7] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 management of IPsec SAs by populating and managing the SPD and the SAD. +-----------------------------------------+ | IPsec Management Application | Client or | I2NSF Client | App Gateway +-----------------------------------------+ | Client Facing Interface +-----------------------------------------+ Vendor| Application Support | Facing<->|-----------------------------------------| Security Interface| SPD, SAD and PAD Entries Distr. | Controller +-----------------------------------------+ | NSF Facing Interface +-----------------------------------------+ | I2NSF Agent | Network |-----------------------------------------| Security | IPsec (SPD,SAD) | Function (NSF) |-----------------------------------------| | Data Protection and Forwarding | +-----------------------------------------+ Figure 2: IKE-less case: IPsec (no IKE) in the NSF As shown in Figure 2, applications for flow protection run on the top of the Security Controller. When an administrator enforces flow- based protection policies through the Client Facing Interface, the Security 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. 5.2.1. Interface Requirements for IKE-less case In order to support the IKE-less case, the following requirements need to be met: o A YANG data model for configuration data for SPD and SAD and for state data for SAD. o In scenarios where multiple controllers are implicated, SDN-based IPsec management services may require a mechanism to discover which Security Controller is managing a specific NSF. Moreover, an east-west interface [RFC7426] is required to exchange IPsec- related information. NOTE: A possible east-west protocol for this IKE-less case could be IKEv2. However, this needs to be explore since the IKEv2 peers would be the Security Controllers. Marin-Lopez, et al. Expires February 6, 2020 [Page 8] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 Specifically, the IKE-less case assumes that the SDN 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 Rekey of the IPsec SAs based on notifications from the NSF (i.e. expire). o Generation of the IPsec SAs when required based on notifications (i.e. sadb-acquire) from the NSF. o NAT Traversal discovery and management. Additionally to these functions, another set of tasks must be performed by the Security Controller (non-exhaustive list): o IPsec SA's SPI random generation. o Cryptographic algorithm/s selection. o Usage of extended sequence numbers. o Establishment of proper traffic selectors. 5.3. IKE case vs IKE-less case In principle, IKE case is easier to deploy than IKE-less case because current gateways typically have an IKEv2/IPsec implementation. Moreover hosts can install easily an IKE implementation. As downside, the NSF needs more resources to hold IKEv2. Moreover, the IKEv2 implementation needs to implement an internal interface so that the IKE configuration sent by the Security Controller can be enforced in runtime. Alternatively, IKE-less case allows lighter NSFs (no IKEv2 implementation), which benefits the deployment in constrained NSFs. Moreover, IKEv2 does not need to be performed in gateway-to-gateway and host-to-host scenarios under the same Security Controller (see Section 7.1). On the contrary, the overload of creating and managing IPsec SAs is shifted to the Security 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 Security Controller have to deal with the latency Marin-Lopez, et al. Expires February 6, 2020 [Page 9] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 existing in the path between the Security 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 our contribution but a general aspect in any SDN-based network. In summary, this overload may create some scalability and performance issues when the number of NSFs is high. Nevertheless, literature around SDN-based network management using a centralized Security Controller is aware about scalability and performance issues and solutions have been already provided and discussed (e.g. hierarchical Security Controllers; having multiple replicated Security Controllers, dedicated high-speed management networks, etc). In the context of SDN-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 Section 7.1) instead of waiting for notifications (e.g. a notification sadb-acquire when a new IPsec SA is required) to proceed with the IPsec SA installations (reactive mode). Another way to reduce the overhead and the potential scalability and performance issues in the Security Controller is to apply the IKE case described in this document, since the IPsec SAs are managed between NSFs without the involvement of the Security Controller at all, except by the initial IKE configuration provided by the Security Controller. Other solutions, such as Controller-IKE [I-D.carrel-ipsecme-controller-ike], have proposed that NSFs provide their DH public keys to the Security Controller, so that the Security 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 we discuss in section Section 9. The main reason is that the NSFs are generating the session keys and not the Security Controller. 5.3.1. Rekeying process. For IKE case, the rekeying process is carried out by IKEv2, following the information defined in the SPD and SAD. Therefore, connections will live unless something different is required by the administrator or the Security Controller detects something wrong. Traditionally, during a rekey process of the IPSec SA using IKE, a bundle of inbound and outbound IPsec SAs is taken into account from the perspective of one of the NSFs. For example, if the inbound IPsec SA expires both the inbound and outbound IPsec SA are rekeyed at the same time in that NSF. However, when IKE is not used, we have Marin-Lopez, et al. Expires February 6, 2020 [Page 10] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 followed a different approach to avoid any packet loss during rekey: the Security Controller installs first the new inbound SAs in both NSFs and then, the outbound IPsec SAs. In other words, for the IKE-less case, the Security Controller needs to take care of the rekeying process. When the IPsec SA is going to expire (e.g. IPsec SA soft lifetime), it has to create a new IPsec SA and remove the old one. This rekeying process starts when the Security Controller receives a sadb-expire notification or it decides so, based on lifetime state data obtained from the NSF. To explain 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 Security Controller chooses two random values as SPI for the new inbound IPsec SAs: for example, SPIa2 for A and SPIb2 for B. These numbers MUST NOT be in conflict with any IPsec SA in A or B. Then, the Security 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 Security Controller receives confirmation from A and B, the controller knows that the inbound IPsec A are correctly installed. Then it proceeds to send in parallel to A and B, the outbound IPsec SAs: it sends 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 Security Controller receives confirmation from A and B that the outbound IPsec SAs have been installed, the Security 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 Security Controller is trying to install a new inbound IPsec SA) the Security 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 fails (e.g. the NSF A reports an error when the Security Controller is trying to install the new outbound IPsec SA), the Security 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. Marin-Lopez, et al. Expires February 6, 2020 [Page 11] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 If the steps 1 an 2 are successful and the step 3 fails the Security 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 Security Controller may reattempt to remove the old inbound and outbound 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 the hard lifetime is reached. 5.3.2. NSF state loss. If one of the NSF restarts, it will lose the IPsec state (affected NSF). By default, the Security 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 IKE-less case. In both cases, the Security Controller is aware of the affected NSF (e.g. the NETCONF/TCP connection is broken with the affected NSF, the Security Controller is receiving sadb-bad-spi notification from a particular NSF, etc.). Moreover, the Security Controller has a register about all the NSFs that have IPsec SAs with the affected NSF. Therefore, it knows the affected IPsec SAs. In IKE case, the Security Controller will configure the affected NSF with the new IKEv2, SPD and PAD information. It has also to send new parameters (e.g. a new fresh PSK for authentication) to the NSFs which have IKEv2 SAs and IPsec SAs with the affected NSF. Finally, the Security Controller will instruct the affected NSF to start the IKEv2 negotiation with the new configuration. In IKE-less case, if the Security Controller detects that a NSF has lost the IPsec SAs it will delete the old IPsec SAs on the non-failed nodes, established with the failed node (step 1). This prevents the non-failed nodes from leaking plaintext. If the affected node comes to live, the Security Controller will configure the new inbound IPsec SAs between the affected node and all the nodes it was talking to (step 2). After these inbound IPsec SAs have been established, the Security Controller can configure the outbound IPsec SAs in parallel (step 3). Nevertheless other more optimized options can be considered (e.g. making the IKEv2 configuration permanent between reboots). 5.3.3. 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. If there is a NAT network configured between two peers, it is required to activate Marin-Lopez, et al. Expires February 6, 2020 [Page 12] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 the usage of UDP or TCP/TLS encapsulation for ESP packets ([RFC3948], [RFC8229]). Note that the usage of IPsec transport mode when NAT is required MUST NOT be used in this specification. On the contrary, the IKE-less case does not have any protocol in the NSFs to detect whether they are located behind a NAT or not. However, the SDN paradigm generally assumes the Security Controller has a view of the network under its control. This view is built either requesting information to the NSFs under its control, or because these NSFs inform the Security Controller. Based on this information, the Security Controller can 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/TLS encapsulation of ESP packets ([RFC3948], [RFC8229]). For example, the Security Controller could directly request the NSF for specific data such as networking configuration, NAT support, etc. Protocols such as NETCONF or SNMP can be used here. For example, RFC 7317 [RFC7317] provides a YANG data model for system management or [RFC8512] a data model for NAT management. The Security Controller can use this NETCONF module with a NSF to collect NAT information or even configure a NAT network. In any case, if this NETCONF module is not available in the NSF and the Security Controller does not have a mechanism to know whether a host is behind a NAT or not, then the IKE case should be the right choice and not the IKE-less case. 5.3.4. NSF Discovery The assumption in this document is that, for both cases, before a NSF can operate in this system, it MUST be registered in the Security Controller. In this way, when the NSF comes to live and establishes a connection to the Security Controller, it knows that the NSF is valid for joining the system. Either during this registration process or when the NSF connects with the Security Controller, the Security Controller MUST discover certain capabilities of this NSF, such as what is the cryptographic suite supported, authentication method, the support of the IKE case or the IKE-less case, etc. This discovery process is out of the scope of this document. 6. YANG configuration data models In order to support the IKE and IKE-less cases we have modeled the different parameters and values that must be configured to manage IPsec SAs. Specifically, IKE requires modeling IKEv2, SPD and PAD, while IKE-less case requires configuration models for the SPD and SAD. We have defined three models: ietf-ipsec-common (Appendix A), Marin-Lopez, et al. Expires February 6, 2020 [Page 13] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 ietf-ipsec-ike (Appendix B, IKE case), ietf-ipsec-ikeless (Appendix C, IKE-less case). Since the model ietf-ipsec-common has only typedef and groupings common to the other modules, we only show a simplified view of the ietf-ipsec-ike and ietf-ipsec-ikeless models. 6.1. IKE case model 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: We have observed that many implementations integrate PAD configuration as part of the IKEv2 configuration). module: ietf-ipsec-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? string | | +--:(gnx509) | | | +--rw gnx509? string | | +--:(id-key) | | | +--rw id-key? string | | +--:(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 uint8 | +--rw pre-shared Marin-Lopez, et al. Expires February 6, 2020 [Page 14] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 | | +--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? ct:x509 | +--rw private-key? binary | +--rw ca-data* ct:x509 | +--rw crl-data? ct:crl | +--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? boolean | +--rw ike-sa-lifetime-soft | | +--rw rekey-time? uint32 | | +--rw reauth-time? uint32 | +--rw ike-sa-lifetime-hard | | +--rw over-time? uint32 | +--rw authalg* ic:integrity-algorithm-type | +--rw encalg* ic:encryption-algorithm-type | +--rw dh-group? pfs-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? uint64 | | +--rw traffic-selector | | | +--rw local-subnet inet:ip-prefix | | | +--rw remote-subnet inet:ip-prefix | | | +--rw inner-protocol? ipsec-inner-protocol | | | +--rw local-ports* [start end] Marin-Lopez, et al. Expires February 6, 2020 [Page 15] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 | | | | +--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* integrity-algorithm-type | | | | +--rw encryption* encryption-algorithm-type | | | | +--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? yang:hex-string | | | +--rw ecn? boolean | | +--rw spd-mark | | +--rw mark? uint32 | | +--rw mask? yang:hex-string | +--rw child-sa-info | | +--rw pfs-groups* pfs-group | | +--rw child-sa-lifetime-soft | | | +--rw time? uint32 | | | +--rw bytes? uint32 | | | +--rw packets? uint32 | | | +--rw idle? uint32 | | | +--rw action? ic:lifetime-action | | +--rw child-sa-lifetime-hard | | +--rw time? uint32 | | +--rw bytes? uint32 | | +--rw packets? uint32 | | +--rw idle? uint32 | +--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 Marin-Lopez, et al. Expires February 6, 2020 [Page 16] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 | | +--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? uint64 +--ro half-open? uint64 +--ro half-open-cookies? uint64 Appendix D 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. IKE-less case model 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 simplications. For example, each IPsec policy (spd-entry) contains one traffic selector, instead a list of them. The reason is that we have observed real kernel implementations only admit a traffic selector per IPsec policy. The definition of the SAD model has been extracted from the specification in section 4.4.2 in [RFC4301]. Note that this model not only allows to associate an IPsec SA with its corresponding policy through the specific traffic selector but also an identifier (reqid). The notifications model has been defined using as reference the PF_KEYv2 standard in [RFC2367]. module: ietf-ipsec-ikeless +--rw ipsec-ikeless +--rw spd | +--rw spd-entry* [name] | +--rw name string | +--rw direction? ic:ipsec-traffic-direction | +--rw reqid? uint64 | +--rw ipsec-policy-config | +--rw anti-replay-window? uint64 | +--rw traffic-selector | | +--rw local-subnet inet:ip-prefix | | +--rw remote-subnet inet:ip-prefix Marin-Lopez, et al. Expires February 6, 2020 [Page 17] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 | | +--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? | | +--rw esp-algorithms | | | +--rw integrity* integrity-algorithm-type | | | +--rw encryption* encryption-algorithm-type | | | +--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? yang:hex-string | | +--rw ecn? boolean | +--rw spd-mark | +--rw mark? uint32 | +--rw mask? yang:hex-string +--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-number-counter? uint64 | +--rw seq-overflow? boolean | +--rw anti-replay-window? uint32 | +--rw traffic-selector | | +--rw local-subnet inet:ip-prefix | | +--rw remote-subnet 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] Marin-Lopez, et al. Expires February 6, 2020 [Page 18] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 | | +--rw start inet:port-number | | +--rw end inet:port-number | +--rw protocol-parameters? ic:ipsec-protocol-parameters | +--rw mode? ic:ipsec-mode | +--rw esp-sa | | +--rw encryption | | | +--rw encryption-algorithm? ic:encryption-algorithm-type | | | +--rw key? yang:hex-string | | | +--rw iv? yang:hex-string | | +--rw integrity | | +--rw integrity-algorithm? ic:integrity-algorithm-type | | +--rw key? yang:hex-string | +--rw sa-lifetime-hard | | +--rw time? uint32 | | +--rw bytes? uint32 | | +--rw packets? uint32 | | +--rw idle? uint32 | +--rw sa-lifetime-soft | | +--rw time? uint32 | | +--rw bytes? uint32 | | +--rw packets? uint32 | | +--rw idle? uint32 | | +--rw action? ic: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? yang:hex-string | | +--rw ecn? boolean | +--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? uint32 | +--ro packets? uint32 | +--ro idle? uint32 +--ro replay-stats +--ro replay-window? uint64 +--ro packet-dropped? uint64 +--ro failed? uint32 +--ro seq-number-counter? uint64 notifications: Marin-Lopez, et al. Expires February 6, 2020 [Page 19] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 +---n sadb-acquire | +--ro ipsec-policy-name string | +--ro traffic-selector | +--ro local-subnet inet:ip-prefix | +--ro remote-subnet inet:ip-prefix | +--ro inner-protocol? ipsec-inner-protocol | +--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 | +--ro ipsec-sa-name string | +--ro soft-lifetime-expire? boolean | +--ro lifetime-current | +--ro time? uint32 | +--ro bytes? uint32 | +--ro packets? uint32 | +--ro idle? uint32 +---n sadb-seq-overflow | +--ro ipsec-sa-name string +---n sadb-bad-spi +--ro spi uint32 Appendix E shows an example of IKE-less case configuration for a NSF, in transport mode (host-to-host), with NSFs authentication based on shared secrets. For the IKE-less case, Appendix F shows examples of IPsec SA expire, acquire, sequence number overflow and bad SPI notifications. 7. Use cases examples This section explains how different traditional configurations, that is, host-to-host and gateway-to-gateway, are deployed using this SDN- based IPsec management service. In turn, these configurations will be typical in modern networks where, for example, virtualization will be key. 7.1. Host-to-host or gateway-to-gateway under the same Security Controller Marin-Lopez, et al. Expires February 6, 2020 [Page 20] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 +----------------------------------------+ | Security Controller | | | (1)| +--------------+ (2)+--------------+ | Flow-based ------> |Translate into|--->| South. Prot. | | Security. Pol. | |IPsec Policies| | | | | +--------------+ +--------------+ | | | | | | | | | +--------------------------|-----|-------+ | | | (3) | |-------------------------+ +---| V V +----------------------+ +----------------------+ | NSF A |<=======>| NSF B | |IKEv2/IPsec(SPD/PAD) | |IKEv2/IPsec(SPD/PAD) | +----------------------+ (4) +----------------------+ Figure 3: Host-to-host / gateway-to-gateway single Security Controller for the IKE case. Figure 3 describes the IKE case: 1. The administrator defines general flow-based security policies. The Security Controller looks for the NSFs involved (NSF A and NSF B). 2. The Security Controller generates IKEv2 credentials for them and translates the policies into SPD and PAD entries. 3. The Security 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 Security 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. 4. If the previous step is successful, the flow is protected by means of the IPsec SA established with IKEv2. Marin-Lopez, et al. Expires February 6, 2020 [Page 21] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 +----------------------------------------+ | (1) Security Controller | Flow-based | | Security -----------| | Policy | V | | +---------------+ (2)+-------------+ | | |Translate into |--->| South. Prot.| | | |IPsec policies | | | | | +---------------+ +-------------+ | | | | | | | | | +-------------------------| --- |--------+ | | | (3) | |----------------------+ +--| V V +------------------+ +------------------+ | NSF A |<=====>| NSF B | |IPsec(SPD/SAD) | 4) |IPsec(SPD/SAD) | +------------------+ +------------------+ Figure 4: Host-to-host / gateway-to-gateway single Security Controller for IKE-less case. In the IKE-less case, flow-based security policies defined by the administrator are translated into IPsec SPD entries and inserted into the corresponding NSFs. Besides, fresh SAD entries will be also generated by the Security Controller and enforced in the NSFs. In this case, the Security Controller does not run any IKEv2 implementation (neither the NSFs), and it provides the cryptographic material for the IPsec SAs. These keys will be also distributed securely through the southbound interface. Note that this is possible because both NSFs are managed by the same Security Controller. Figure 4 describes the IKE-less case, when a data packet needs to be protected in the path between the NSF A and NSF B: 1. The administrator establishes the flow-based security policies, and the Security Controller looks for the involved NSFs. 2. The Security Controller translates the flow-based security policies into IPsec SPD and SAD entries. 3. The Security Controller inserts these entries in both NSF A and NSF B IPsec databases (SPD and SAD). The following text describes how this happens between two NSFs A and B: Marin-Lopez, et al. Expires February 6, 2020 [Page 22] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 * The Security Controller chooses two random values as SPIs: for example, SPIa1 for NSF A and SPIb1 for NSF B. These numbers MUST NOT be in conflict with any IPsec SA in NSF A or NSF B. It also generates fresh cryptographic material for the new inbound/outbound IPsec SAs and their parameters and send simultaneously the new inbound IPsec SA with SPIa1 and new outbound IPsec SAs with SPIb1 to NSF A; and the new inbound IPsec SA with SPIb1 and new outbound IPsec SAs with SPIa1 to B, together with the corresponding IPsec policies. * Once the Security Controller receives confirmation from NSF A and NSF B, the controller knows that the IPsec SAs are correctly installed and ready. If some of the operations described above fails (e.g. the NSF A reports an error when the Security Controller is trying to install the SPD entry, the new inbound and outbound IPsec SAs) the Security Controller must perform rollback operations by deleting any new inbound or outbound SA and SPD entry that had been successfully installed in any of the NSFs (e.g NSF B) and stop the process (NOTE: the Security Controller may retry several times before giving up). Other alternative to this operation is: the Security 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 to the new outbound IPsec SAs. However, this may increase the latency to complete the process. As an advantage, no traffic is sent over the network until the IPsec SAs are completely operative. In any case other alternatives may be possible. Finally, it is worth mentioning that the Security Controller associates a lifetime to the new IPsec SAs. When this lifetime expires, the NSF will send a sadb-expire notification to the Security Controller in order to start the rekeying process. 4. The flow is protected with the IPsec SA established by the Security Controller. 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 Security 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 Security Controller that needs SAD entries with the IPsec SAs to process the data packet. In such as reactive mode, since IPsec policies are already installed in the SPD, the Security Controller installs first the new IPsec SAs in NSF A and B with the operations described in step 3 but without sending any IPsec policies. Again, if some of the operations installing the Marin-Lopez, et al. Expires February 6, 2020 [Page 23] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 new inbound/outbound IPsec SAs fail, the Security Controller stops the process and performs a rollback operation by deleting any new inbound/outbound SAs that had been successfully installed. Both NSFs could be two hosts that exchange traffic and require to establish an end-to-end security association to protect their communications (host-to-host) or two 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. Beside, IaaS services providing virtualization environments are deployments solutions based on IPsec to provide secure channels between virtual instances (host- to-host) and providing VPN solutions for virtualized networks (gateway-to-gateway). In general (for IKE and IKE-less cases), this system has various advantages: 1. It allows to create IPsec SAs among two NSFs, based only on the application of general Flow-based Security Policies at the application layer. Thus, administrators can manage all security associations in a centralized point with an abstracted view of the network. 2. Any NSF deployed in the system does not need manual configuration, therefore allowing its deployment in an automated manner. 7.2. Host-to-host or gateway-to-gateway under different Security Controllers It is also possible that two NSFs (i.e. NSF A and NSF B) are under the control of two different Security Controllers. This may happen, for example, when two organizations, namely Enterprise A and Enterprise B, have their headquarters interconnected through a WAN connection and they both have deployed a SDN-based architecture to provide connectivity to all their clients. Marin-Lopez, et al. Expires February 6, 2020 [Page 24] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 +-------------+ +-------------+ | | | | Flow-based| Security |<=========>| Security <--Flow-based Sec. Pol.--> Controller | (3) | Controller | Sec. Pol. (1) | A | | B | (2) +-------------+ +-------------+ | | | (4) (4) | V V +--------------------+ +--------------------+ | NSF A |<=======>| NSF B | |IKEv2/IPsec(SPD/PAD)| |IKEv2/IPsec(SPD/PAD)| +--------------------+ (5) +--------------------+ Figure 5: Different Security Controllers in the IKE case. Figure 5 describes IKE case when two Security Controllers are involved in the process. 1. The A's administrator establishes general Flow-based Security Policies in Security Controller A. 2. The B's administrator establishes general Flow-based Security Policies in Security Controller B. 3. The Security Controller A realizes that protection is required between the NSF A and NSF B, but the NSF B is under the control of another Security Controller (Security Controller B), so it starts negotiations with the other controller to agree on the IPsec SPD policies and IKEv2 credentials for their respective NSFs. NOTE: This may require extensions in the East/West interface. 4. Then, both Security Controllers enforce the IKEv2 credentials, related parameters and the SPD and PAD entries in their respective NSFs. 5. The flow is protected with the IPsec SAs established with IKEv2 between both NSFs. Marin-Lopez, et al. Expires February 6, 2020 [Page 25] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 +--------------+ +--------------+ | | | | Flow-based. ---> | | <---Flow-based Prot. | Security |<===========>| Security |Sec. Pol.(1)| Controller | (3) | Controller |Pol. (2) | A | | B | +--------------+ +--------------+ | | | (4) (4) | V V +--------------+ (5) +--------------+ | NSF A |<==============>| NSF B | |IPsec(SPD/SAD)| |IPsec(SPD/SAD)| +--------------+ +--------------+ Figure 6: Different Security Controllers in the IKE-less case. Figure 6 describes IKE-less case when two Security Controllers are involved in the process. 1. The A's administrator establishes general Flow Protection Policies in Security Controller A. 2. The B's administrator establishes general Flow Protection Policies in Security Controller B. 3. The Security Controller A realizes that the flow between NSF B and NSF B MUST be protected. Nevertheless, it notices that NSF B is under the control of another Security Controller B, so it starts negotiations with the other controller to agree on the IPsec SPD and SAD entries that define the IPsec SAs. NOTE: It would worth evaluating IKEv2 as the protocol for the East/West interface in this case. 4. Once the Security Controllers have agreed on the key material and the details of the IPsec SAs, they both enforce this information into their respective NSFs. 5. The flow is protected with the IPsec SAs established by both Security Controllers in their respective NSFs. 8. 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: Marin-Lopez, et al. Expires February 6, 2020 [Page 26] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 URI: urn:ietf:params:xml:ns:yang:ietf-ipsec-common Registrant Contact: The I2NSF WG of the IETF. XML: N/A, the requested URI is an XML namespace. URI: urn:ietf:params:xml:ns:yang:ietf-ipsec-ike Registrant Contact: The I2NSF WG of the IETF. XML: N/A, the requested URI is an XML namespace. URI: urn:ietf:params:xml:ns:yang:ietf-ipsec-ikeless Registrant Contact: The I2NSF WG of the IETF. 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: Name: ietf-ipsec-common Namespace: urn:ietf:params:xml:ns:yang:ietf-ipsec-common Prefix: ic Reference: RFC XXXX Name: ietf-ipsec-ike Namespace: urn:ietf:params:xml:ns:yang:ietf-ipsec-ike Prefix: ike Reference: RFC XXXX Name: ietf-ipsec-ikeless Namespace: urn:ietf:params:xml:ns:yang:ietf-ipsec-ikeless Prefix: ikeless Reference: RFC XXXX 9. 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 [RFC8192]. On the one hand, it is important to note that there MUST exit a security association between the Security Controller and the NSFs to protect of the critical information (cryptographic keys, configuration parameter, etc...) exchanged between these entities. For example, when NETCONF is used as southbound protocol between the Security Controller and the NSFs, it is defined that TLS or SSH security association MUST be established between both entities. 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 in the startup Marin-Lopez, et al. Expires February 6, 2020 [Page 27] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 configuration datastore in the NSF before the NSF contacts with the Security Controller. Moreover, the startup configuration datastore MUST be pre-configured with the required ALLOW policies that allow to communicate the NSF with the Security Controller once the NSF is deployed. This pre-configuration step is not carried out by the Security Controller but by some other entity before the NSF deployment. In this manner, when the NSF starts/reboots, it will always apply first the configuration in the startup configuration before contacting the Security Controller. Finally, we have divided this section 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 Security Controller, as typically in the SDN paradigm, is a target for different type of attacks. Thus, the Security Controller is a key entity in the infrastructure and MUST be protected accordingly. In particular, the Security Controller will handle cryptographic material so that the attacker may try to access this information. Although we can assume this attack will not likely to happen due to the assumed security measurements to protect the Security Controller, it deserves some analysis in the hypothetical case the attack occurs. The impact is different depending on the IKE case or IKE-less case. 9.1. IKE case In IKE case, the Security Controller sends IKE credentials (PSK, public/private keys, certificates, etc.) to the NSFs using the security association between Security Controller and NSFs. The general recommendation is that the Security Controller MUST NOT store the IKE credentials after distributing them. Moreover, the NSFs MUST NOT allow the reading of these values once they have been applied by the Security Controller (i.e. write only operations). One option is to return always the same value (i.e. all 0s) if a read operation is carried out. If the attacker has access to the Security 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. If PSK authentication is used in IKEv2, the Security Controller MUST remove the PSK immediately after generating and distributing it. Moreover, the PSK MUST have a proper length (e.g. minimum 128 bit length) and strength. When public/private keys are used, the Security Controller MAY generate both public key and private key. In such a case, the Security Controller MUST remove the associated private key immediately after distributing them to the NSFs. Alternatively, the NSF could generate the private key and export only the public key to the Security Controller. If certificates are used, the NSF MAY generate the Marin-Lopez, et al. Expires February 6, 2020 [Page 28] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 private key and exports the public key for certification to the Security Controller. How the NSF generates these cryptographic material (public key/private keys) and export the public key, or it is instructed to do so, it is out of the scope of this document. 9.2. IKE-less case In the IKE-less case, the Security Controller sends the IPsec SA information to the NSF's SAD that includes the private session keys required for integrity and encryption. The general recommendation is that it MUST NOT store the keys after distributing them. Moreover, the NSFs receiving private key material MUST NOT allow the reading of these values by any other entity (including the Security Controller itself) once they have been applied (i.e. write only operations) into the NSFs. Nevertheless, if the attacker has access to the Security 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. 9.3. YANG modules The YANG module specified in this document defines a schema for data that is designed to be accessed via network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [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: The YANG modules describe configuration data for the IKE case (ietf- ipsec-ike) and IKE-less case (ietf-ipsec-ikeless). There is a common module (ietf-ipsec-common) used in both cases. For the IKE case (ietf-ipsec-ike): Marin-Lopez, et al. Expires February 6, 2020 [Page 29] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 /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), 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 a allow policy), and in general changing the IKE SA conditions and credentials between any NSF. For the IKE-less case (ietf-ipsec-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-ipsec-ike): /ipsec-ike/pad: This container includes sensitive information to read operations. This information should never 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-ipsec-ikeless): /ipsec-ikeless/sad/ipsec-sa-config/esp-sa: This container includes symmetric keys for the IPsec SAs. For example, encryption/key contains a ESP encryption key value and encryption/iv contains a initialization vector value. Similarly, integrity/key has 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. Marin-Lopez, et al. Expires February 6, 2020 [Page 30] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 10. 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, Carlos J. Bernardos, Alejandro Perez-Mendez, Alejandro Abad-Carrascosa, Ignacio Martinez and Ruben Ricart for their valuable comments. 11. References 11.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4301] Kent, S. and K. Seo, "Security Architecture for the Internet Protocol", RFC 4301, DOI 10.17487/RFC4301, December 2005, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [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, . [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, . [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, . [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, . [RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration Access Control Model", STD 91, RFC 8341, DOI 10.17487/RFC8341, March 2018, . Marin-Lopez, et al. Expires February 6, 2020 [Page 31] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, . 11.2. 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.ietf-i2nsf-terminology] Hares, S., Strassner, J., Lopez, D., Xia, L., and H. Birkholz, "Interface to Network Security Functions (I2NSF) Terminology", draft-ietf-i2nsf-terminology-08 (work in progress), July 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.X.1252] "Baseline Identity Management Terms and Definitions", April 2010. [ITU-T.X.800] "Security Architecture for Open Systems Interconnection for CCITT Applications", March 1991. [ITU-T.Y.3300] "Recommendation ITU-T Y.3300", June 2014. [libreswan] The Libreswan Project, "Libreswan VPN software", August 2019. [netconf-vpn] Stefan Wallin, "Tutorial: NETCONF and YANG", January 2014. [ONF-OpenFlow] ONF, "OpenFlow Switch Specification (Version 1.4.0)", October 2013. [ONF-SDN-Architecture] "SDN Architecture", June 2014. Marin-Lopez, et al. Expires February 6, 2020 [Page 32] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 [RFC2367] McDonald, D., Metz, C., and B. Phan, "PF_KEY Key Management API, Version 2", RFC 2367, DOI 10.17487/RFC2367, July 1998, . [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [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, . [RFC6071] Frankel, S. and S. Krishnan, "IP Security (IPsec) and Internet Key Exchange (IKE) Document Roadmap", RFC 6071, DOI 10.17487/RFC6071, February 2011, . [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, . [RFC7317] Bierman, A. and M. Bjorklund, "A YANG Data Model for System Management", RFC 7317, DOI 10.17487/RFC7317, August 2014, . [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, . [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, . [RFC8229] Pauly, T., Touati, S., and R. Mantha, "TCP Encapsulation of IKE and IPsec Packets", RFC 8229, DOI 10.17487/RFC8229, August 2017, . Marin-Lopez, et al. Expires February 6, 2020 [Page 33] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 [RFC8512] Boucadair, M., Ed., Sivakumar, S., Jacquenet, C., Vinapamula, S., and Q. Wu, "A YANG Module for Network Address Translation (NAT) and Network Prefix Translation (NPT)", RFC 8512, DOI 10.17487/RFC8512, January 2019, . [strongswan] CESNET, "StrongSwan: the OpenSource IPsec-based VPN Solution", August 2019. Marin-Lopez, et al. Expires February 6, 2020 [Page 34] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 Appendix A. Appendix A: Common YANG model for IKE and IKE-less cases file "ietf-ipsec-common@2019-08-05.yang" module ietf-ipsec-common { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-ipsec-common"; prefix "ipsec-common"; import ietf-inet-types { prefix inet; } import ietf-yang-types { prefix yang; } organization "IETF I2NSF Working Group"; contact "WG Web: WG List: Author: Rafael Marin-Lopez Author: Gabriel Lopez-Millan Author: Fernando Pereniguez-Garcia "; description "Common Data model for the IKE and IKE-less cases defined by the SDN-based IPsec flow protection service. Copyright (c) 2019 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', Marin-Lopez, et al. Expires February 6, 2020 [Page 35] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 '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 "2019-08-05" { description "Revision 06"; reference "RFC XXXX: YANG Groupings and typedef for IKE and IKE-less case"; } typedef encryption-algorithm-type { type uint16; description "The encryption algorithm is specified with a 16-bit number extracted from IANA Registry. The acceptable values MUST follow the requirement levels for encryption algorithms for ESP and IKEv2."; reference "IANA Registry- 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 integrity-algorithm-type { type uint16; description "The integrity algorithm is specified with a 16-bit number extracted from IANA Registry. The acceptable values MUST follow the requirement levels for encryption algorithms for ESP and IKEv2."; reference "IANA Registry- 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 { Marin-Lopez, et al. Expires February 6, 2020 [Page 36] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 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 espintls { description "ESP in TCP encapsulation using TLS."; 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 { description "NOT ESP encapsulation."; } } description "Types of ESP encapsulation when Network Address Translation (NAT) is present between two NSFs."; Marin-Lopez, et al. Expires February 6, 2020 [Page 37] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 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 over the IPsec SA that reached the lifetime. There are three posible options: terminate-clear, terminate-hold and replace."; reference "Section 4.5 in RFC 4301."; } typedef ipsec-traffic-direction { Marin-Lopez, et al. Expires February 6, 2020 [Page 38] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 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 means the traffic that enters the NSF and outbound is the traffic that is sent from the NSF."; reference "Section 5 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."; } typedef ipsec-inner-protocol { type union { type uint8; type enumeration { enum any { Marin-Lopez, et al. Expires February 6, 2020 [Page 39] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 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 specify the IP protocol number with an uint8 or ANY defining an enumerate with value 256 to indicate the protocol number."; 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 port information."; leaf espencap { type esp-encap; 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 "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. "; Marin-Lopez, et al. Expires February 6, 2020 [Page 40] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 } reference "RFC 3947 and RFC 8229."; } grouping lifetime { description "Different lifetime values limited to an IPsec SA."; leaf time { type uint32; 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 uint32; 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; default 0; description "When a NSF stores an IPsec SA, it consumes system resources. In an idle NSF 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."; Marin-Lopez, et al. Expires February 6, 2020 [Page 41] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 } 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; description "End port number."; } 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; 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 from the outer header. This is the default value."; Marin-Lopez, et al. Expires February 6, 2020 [Page 42] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 } 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."; reference "Section 8.1 in RFC 4301."; } leaf bypass-dscp { type boolean; default true; description "If DSCP (Differentiated Services Code Point) values in the inner header have to be used to select one IPsec SA among several that match the traffic selectors for an outbound packet"; reference "Section 4.4.2.1. in RFC 4301."; } leaf dscp-mapping { type yang:hex-string; description "DSCP values allowed for packets carried over this IPsec SA."; reference "Section 4.4.2.1. in RFC 4301."; } leaf ecn { type boolean; default false; description "Explicit Congestion Notification (ECN). If true copy CE bits to inner header."; reference "Section 5.1.2 and Annex C in RFC 4301."; } Marin-Lopez, et al. Expires February 6, 2020 [Page 43] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 } 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-subnet { type inet:ip-prefix; mandatory true; description "Local IP address subnet."; } leaf remote-subnet { type inet:ip-prefix; mandatory true; description "Remote IP address subnet."; } 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."; } 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."; } reference "Section 4.4.1.2 in RFC 4301."; } grouping ipsec-policy-grouping { Marin-Lopez, et al. Expires February 6, 2020 [Page 44] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 description "Holds configuration information for an IPsec SPD entry."; leaf anti-replay-window { type uint64; default 32; description "A 64-bit counter used to determine whether an inbound ESP packet is a replay."; reference "Section 4.4.2.1 in RFC 4301."; } container traffic-selector { description "Packets are selected for processing actions based on the IP and inner protocol header information, selectors, matched against entries in the SPD."; 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 Marin-Lopez, et al. Expires February 6, 2020 [Page 45] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 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 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. True 64 bit counter, False 32 bit."; } 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 this flag MUST be false."; } 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 February 6, 2020 [Page 46] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 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 integrity-algorithm-type; default 0; ordered-by user; description "Configuration of ESP authentication based on the specified integrity algorithm. With AEAD algorithms, the integrity node is not used."; reference "Section 3.2 in RFC 4303."; } leaf-list encryption { type encryption-algorithm-type; default 20; ordered-by user; description "Configuration of ESP encryption algorithms. The default value is 20 (ENCR_AES_GCM_16)."; 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."; } Marin-Lopez, et al. Expires February 6, 2020 [Page 47] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 container tunnel { when "../mode = 'tunnel'"; uses tunnel-grouping; description "IPsec tunnel endpoints definition."; } } reference "Section 4.4.1.2 in RFC 4301."; } container spd-mark { description "The Mark to set for the IPsec SA of this connection. This option is only available on linux NETKEY/XFRM kernels. It can be used with iptables to create custom iptables rules using CONNMARK. It can also be used with Virtual Tunnel Interfaces (VTI) to direct marked traffic to specific vtiXX devices."; leaf mark { type uint32; default 0; description "Mark used to match XFRM policies and states."; } leaf mask { type yang:hex-string; default 00:00:00:00; description "Mask used to match XFRM policies and states."; } } } } Appendix B. Appendix B: YANG model for IKE case file "ietf-ipsec-ike@2019-08-05.yang" Marin-Lopez, et al. Expires February 6, 2020 [Page 48] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 module ietf-ipsec-ike { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-ipsec-ike"; prefix "ike"; import ietf-inet-types { prefix inet; } import ietf-yang-types { prefix yang; } import ietf-crypto-types { prefix ct; reference "draft-ietf-netconf-crypto-types-10: Common YANG Data Types for Cryptography."; } import ietf-ipsec-common { prefix ic; reference "RFC XXXX: module ietf-ipsec-common, revision 2019-08-05."; } import ietf-netconf-acm { prefix nacm; reference "RFC 8341: Network Configuration Access Control Model."; } organization "IETF I2NSF Working Group"; contact "WG Web: WG List: Author: Rafael Marin-Lopez Author: Gabriel Lopez-Millan Author: Fernando Pereniguez-Garcia "; description "This module contains IPSec IKE case model for the SDN-based Marin-Lopez, et al. Expires February 6, 2020 [Page 49] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 IPsec flow protection service. An NSF will implement this module. Copyright (c) 2019 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 "2019-08-05" { description "Revision 6"; reference "RFC XXXX: YANG model for IKE case."; } typedef ike-spi { type uint64 { range "0..max"; } 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 Marin-Lopez, et al. Expires February 6, 2020 [Page 50] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 "IKE/IPsec configuration is loaded into IKE implementation. The IPsec policies are transferred to the NSF's kernel but the IPsec SAs are not established immediately. The IKE implementation will negotiate the IPsec SAs when the NSF's kernel requests it (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 any packet."; } } description "Different policies to set IPsec SA configuration into NSF's kernel when IKEv2 implementation has started."; } typedef pfs-group { type uint16; description "DH groups for IKE and IPsec SA rekey."; reference "Section 3.3.2 in RFC 7296. Transform Type 4 - Diffie-Hellman Group Transform IDs in IANA Registry - Internet Key Exchange Version 2 (IKEv2) Parameters."; } typedef auth-protocol-type { type enumeration { enum ikev2 { value 2; description "IKEv2 authentication protocol. It is the only 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 enumerate to allow new IKE versions in the Marin-Lopez, et al. Expires February 6, 2020 [Page 51] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 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 method."; reference "RFC 7296 and RFC 7427."; } enum null { description "Null authentication."; reference "RFC 7619."; } } description "Peer authentication method specified in the Peer Authorization Database (PAD)."; } container ipsec-ike { description "IKE configuration for a NSF. It includes PAD parameters, IKE connections information and state data."; container pad { description "Configuration of Peer Authorization Database Marin-Lopez, et al. Expires February 6, 2020 [Page 52] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 (PAD). The PAD contains information about IKE peer (local and remote). Therefore, the Security Controller also stores authentication information for this NSF and can include several entries for the local NSF not only remote peers. Storing local and remote information makes possible to specify that this NSF with identity A will use some particular authentication with remote NSF with identity B and what are the authentication mechanisms allowed to B."; list pad-entry { key "name"; ordered-by user; description "Peer Authorization Database (PAD) entry. It is a list of PAD entries ordered by the Security Controller."; 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."; case ipv4-address{ leaf ipv4-address { type inet:ipv4-address; description "Specifies the identity as a single four (4) octet."; } } 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 Marin-Lopez, et al. Expires February 6, 2020 [Page 53] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 2001:DB8:0:0:8:800:200C:417A."; } } case fqdn-string { leaf fqdn-string { type inet:domain-name; description "Specifies the identity as a Fully-QualifiedDomain 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 RFC822 email address string. An example is, jsmith@example.com. The string MUST NOT contain any terminators e.g., NULL, CR, etc.)."; reference "RFC 822."; } } case dnx509 { leaf dnx509 { type string; description "Specifies the identity as a ASN.1 X.500 Distinguished Name. An example is C=US,O=Example Organisation,CN=John Smith."; reference "RFC 2247."; } } case gnx509 { leaf gnx509 { type string; description "ASN.1 X.509 GeneralName. RFC Marin-Lopez, et al. Expires February 6, 2020 [Page 54] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 3280."; } } case id-key { leaf id-key { type string; 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 "ID_NULL identification used when IKE identification payload is not used." ; reference "RFC 7619."; } } } 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 use a particular peer and the credentials, which will depend on the selected authentication method."; leaf auth-method { type auth-method-type; default pre-shared; description Marin-Lopez, et al. Expires February 6, 2020 [Page 55] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 "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 uint8; mandatory true; description "EAP method type. 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 authentication method is 'eap'."; reference "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."; } 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 { Marin-Lopez, et al. Expires February 6, 2020 [Page 56] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 type uint8; description "The digital signature algorithm is specified with a value extracted from the IANA Registry. Depending on the algorithm, the following leafs must contain information. For example if digital signature involves a certificate then leaf 'cert-data' and 'private-key' will contain this information."; reference "IKEv2 Authentication Method - IANA Registry - Internet Key Exchange Version 2 (IKEv2) Parameters."; } choice public-key { mandatory true; 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."; reference "RFC XXX: Common YANG Data Types for Cryptography."; } leaf cert-data { type ct:x509; description "X.509 certificate data - PEM4."; reference "RFC XXX: Common YANG Data Types for Cryptography."; Marin-Lopez, et al. Expires February 6, 2020 [Page 57] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 } description "If the Security Controller knows that the NSF already owns a private key associated to this public key (the NSF generated the pair public key/private key out of band), it will only configure one of the leaf of this choice. 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 "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."; reference "RFC XXX: Common YANG Data Types for Cryptography."; } leaf-list ca-data { type ct:x509; description "List of trusted Certification Authorities (CA) certificates encoded using ASN.1 distinguished encoding rules (DER)."; reference "RFC XXX: Common YANG Data Types for Cryptography."; } leaf crl-data { type ct:crl; Marin-Lopez, et al. Expires February 6, 2020 [Page 58] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 description "A CertificateList structure, as specified in RFC 5280, encoded using ASN.1 distinguished encoding rules (DER),as specified in ITU-T X.690."; reference "RFC XXX: Common YANG Data Types for Cryptography."; } leaf crl-uri { type inet:uri; description "X.509 CRL certificate URI."; } leaf oscp-uri { type inet:uri; description "OCSP URI."; } 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 be translated in real time by IKE Security Associations established with these nodes."; leaf name { type string; mandatory true; description "Identifier for this connection entry."; } leaf autostartup { type autostartup-type; default add; description Marin-Lopez, et al. Expires February 6, 2020 [Page 59] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 "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 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 so far."; } leaf fragmentation { type boolean; default false; description "Whether or not to enable IKE fragmentation as per RFC 7383 (true or false)."; reference "RFC 7383."; } 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; default 0; description "Time in seconds between each IKE SA rekey.The value 0 means infinite."; } leaf reauth-time { Marin-Lopez, et al. Expires February 6, 2020 [Page 60] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 type uint32; 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; default 0; description "Time in seconds before the IKE SA is removed. The value 0 means infinite."; } reference "RFC 7296."; } leaf-list authalg { type ic:integrity-algorithm-type; default 12; ordered-by user; description "Authentication 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. If this list is empty the default integrity algorithm value assumed is NONE."; } leaf-list encalg { type ic:encryption-algorithm-type; default 12; ordered-by user; 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. If this list is empty the default encryption value assumed is Marin-Lopez, et al. Expires February 6, 2020 [Page 61] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 NULL."; } leaf dh-group { type pfs-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; description "Set the half-open IKE SA timeout duration."; reference "Section 2 in RFC 7296."; } leaf half-open-ike-sa-cookie-threshold { type uint32; description "Number of half-open IKE SAs that activate the cookie mechanism." ; reference "Section 2.6 in RFC 7296."; } container local { leaf local-pad-entry-name { type string; 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; description "Remote peer authentication information. This node points to a specific entry in the PAD where the authorization Marin-Lopez, et al. Expires February 6, 2020 [Page 62] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 information about this particular remote peer is stored. It MUST match a pad-entry-name."; } description "Remote peer authentication information."; } container encapsulation-type { uses ic: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 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; mandatory true; 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 ic:ipsec-policy-grouping; } description "List of entries which will constitute the representation of the SPD. Since we Marin-Lopez, et al. Expires February 6, 2020 [Page 63] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 have IKE in this case, 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 pfs-groups { type pfs-group; default 0; ordered-by user; description "If non-zero, it is required perfect forward secrecy when requesting new IPsec SA. The non-zero value is the required group number. 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 soft. After the lifetime the action is defined in this container in the leaf action."; uses ic:lifetime; leaf action { type ic: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 Marin-Lopez, et al. Expires February 6, 2020 [Page 64] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 in RFC 7296."; } } container child-sa-lifetime-hard { description "IPsec SA lifetime hard. The action will be to terminate the IPsec SA."; uses ic: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; 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."; } Marin-Lopez, et al. Expires February 6, 2020 [Page 65] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 container encapsulation-type { uses ic: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; description "Seconds since this IKE SA has been established."; } leaf current-rekey-time { type uint64; description "Seconds before IKE SA must be rekeyed."; } leaf current-reauth-time { type uint64; description "Seconds before IKE SA must be 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 uint64; description "Total number of active IKE SAs."; } leaf half-open { type uint64; description "Number of half-open active IKE SAs."; } leaf half-open-cookies { Marin-Lopez, et al. Expires February 6, 2020 [Page 66] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 type uint64; 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 */ } Appendix C. Appendix C: YANG model for IKE-less case file "ietf-ipsec-ikeless@2019-08-05.yang" module ietf-ipsec-ikeless { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-ipsec-ikeless"; prefix "ikeless"; import ietf-yang-types { prefix yang; } import ietf-ipsec-common { prefix ic; reference "Common Data model for SDN-based IPSec configuration."; } import ietf-netconf-acm { prefix nacm; reference "RFC 8341: Network Configuration Access Control Model."; } Marin-Lopez, et al. Expires February 6, 2020 [Page 67] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 organization "IETF I2NSF Working Group"; contact "WG Web: WG List: Author: Rafael Marin-Lopez Author: Gabriel Lopez-Millan Author: Fernando Pereniguez-Garcia "; description "Data model for IKE-less case in the SDN-base IPsec flow protection service. Copyright (c) 2019 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 "2019-08-05" { description "Revision 06"; reference "RFC XXXX: YANG model for IKE case."; } container ipsec-ikeless { description Marin-Lopez, et al. Expires February 6, 2020 [Page 68] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 "Container for configuration of the IKE-less case. The container contains two additional containers: 'spd' and 'sad'. The first allows the Security 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; mandatory true; description "SPD entry unique name to identify this entry."; } leaf direction { type ic:ipsec-traffic-direction; description "Inbound traffic or outbound traffic. In the IKE-less case the Security 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 the IKE-less model since, in the IKE case this link is handled internally by IKE."; Marin-Lopez, et al. Expires February 6, 2020 [Page 69] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 } container ipsec-policy-config { description "This container carries the configuration of a IPsec policy."; uses ic: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"; } mandatory true; description "Security Parameter Index (SPI)'s IPsec SA."; Marin-Lopez, et al. Expires February 6, 2020 [Page 70] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 } leaf ext-seq-num { type boolean; default true; description "True if this IPsec SA is using extended sequence numbers. True 64 bit counter, FALSE 32 bit."; } leaf seq-number-counter { type uint64; default 0; description "A 64-bit counter when this IPsec SA is using Extended Sequence Number or 32-bit counter when it is not. It used to generate the initial Sequence Number field in ESP headers."; } 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 this flag MUST BE false."; } leaf anti-replay-window { type uint32; default 32; description "A 32-bit counter and a bit-map (or equivalent) used to determine whether an inbound ESP packet is a replay. If set to 0 no anti-replay mechanism is performed."; } container traffic-selector { uses ic:selector-grouping; description Marin-Lopez, et al. Expires February 6, 2020 [Page 71] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 "The IPsec SA traffic selector."; } leaf protocol-parameters { type ic:ipsec-protocol-parameters; default esp; description "Security protocol of IPsec SA: Only ESP so far."; } leaf mode { type ic:ipsec-mode; 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 ic:encryption-algorithm-type; description "Configuration of ESP encryption. With AEAD algorithms, the integrity node is not used."; } leaf key { nacm:default-deny-all; type yang:hex-string; description "ESP encryption key value."; } leaf iv { nacm:default-deny-all; Marin-Lopez, et al. Expires February 6, 2020 [Page 72] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 type yang:hex-string; description "ESP encryption IV value."; } } container integrity { description "Configuration of integrity for IPSec Encapsulation Security Payload (ESP). This container allows to configure integrity algorithm when no AEAD algorithms are used, and integrity is required."; leaf integrity-algorithm { type ic:integrity-algorithm-type; description "Message Authentication Code (MAC) algorithm to provide integrity in ESP."; } leaf key { nacm:default-deny-all; type yang:hex-string; description "ESP integrity key value."; } } } /*container esp-sa*/ container sa-lifetime-hard { description "IPsec SA hard lifetime. The action associated is terminate and hold."; uses ic:lifetime; } container sa-lifetime-soft { description "IPSec SA soft lifetime."; uses ic:lifetime; leaf action { type ic:lifetime-action; description "Action lifetime: terminate-clear, terminate-hold or replace."; } Marin-Lopez, et al. Expires February 6, 2020 [Page 73] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 } container tunnel { when "../mode = 'tunnel'"; uses ic:tunnel-grouping; description "Endpoints of the IPsec tunnel."; } container encapsulation-type { uses ic: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 ic:lifetime; description "SAD lifetime current."; } container replay-stats { description "State data about the anti-replay window."; leaf replay-window { type uint64; description "Current state of the replay window."; } leaf packet-dropped { type uint64; description "Packets detected out of the replay window and dropped because they are replay packets."; Marin-Lopez, et al. Expires February 6, 2020 [Page 74] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 } leaf failed { type uint32; 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 conforms the SAD."; } /*list sad-entry*/ } /*container sad*/ }/*container ipsec-ikeless*/ /* Notifications */ notification sadb-acquire { description "An IPsec SA is required. The traffic-selector container contains information about the IP packet that triggers the acquire 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 Security 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 { Marin-Lopez, et al. Expires February 6, 2020 [Page 75] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 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 ic:selector-grouping; } } notification sadb-expire { 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 has expired. It is assumed the Security 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 (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."; uses ic:lifetime; } } notification sadb-seq-overflow { description "Sequence overflow notification."; leaf ipsec-sa-name { type string; Marin-Lopez, et al. Expires February 6, 2020 [Page 76] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 mandatory true; description "It contains the SAD entry name (unique) of the IPsec SA that is about to have sequence number overflow and rollover is not permitted. It is assumed the Security Controller will have a copy of the IPsec SA information (except the cryptographic material and state data) indexed by this name (unique identifier) so the it can know all the information (crypto algorithms, etc.) about the IPsec SA that has expired in order to perform a rekey of the IPsec SA."; } } notification sadb-bad-spi { 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."; } } }/*module ietf-ipsec*/ Appendix D. Example of IKE case, tunnel mode (gateway-to-gateway) with X.509 certificate authentication. This example shows a XML configuration file sent by the Security Controller to establish a IPsec Security Association between two NSFs in tunnel mode (gateway-to-gateway) with ESP, and authentication based on X.509 certificates using IKEv2. Marin-Lopez, et al. Expires February 6, 2020 [Page 77] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 Security Controller | /---- Southbound interface -----\ / \ / \ / \ / \ nsf_h1 nsf_h2 h1---- (:1/:100)===== IPsec_ESP_Tunnel_mode =====(:200/:1)-------h2 2001:DB8:1:/64 (2001:DB8:123:/64) 2001:DB8:2:/64 Figure 7: IKE case, tunnel mode , X.509 certicate authentication. nsf_h1_pad 2001:DB8:123::100 digital-signature base64encodedvalue== base64encodedvalue== base64encodedvalue== nsf_h2_pad 2001:DB8:123::200 ikev2 digital-signature 1 base64encodedvalue== base64encodedvalue== nsf_h1-nsf_h2 start ikev2 Marin-Lopez, et al. Expires February 6, 2020 [Page 78] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 false true 60 120 3600 7 3 18 30 15 nsf_h1_pad nsf_h2_pad nsf_h1-nsf_h2 32 2001:DB8:1::0/64 2001:DB8:2::0/64 any 0 0 0 0 protect false true Marin-Lopez, et al. Expires February 6, 2020 [Page 79] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 false false tunnel esp 2 12 false 2001:DB8:123::100 2001:DB8:123::200 clear true false 18 1000000 1000 60 replace 2000000 2000 120 Marin-Lopez, et al. Expires February 6, 2020 [Page 80] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 Appendix E. Example of IKE-less case, transport mode (host-to-host). This example shows a XML configuration file sent by the Security Controller to establish a IPsec Security association between two NSFs in transport mode (host-to-host) with ESP. Security Controller | /---- Southbound interface -----\ / \ / \ / \ / \ nsf_h1 nsf_h2 (:100)===== IPsec_ESP_Transport_mode =====(:200) (2001:DB8:123:/64) Figure 8: IKE-less case, transport mode. in/trans/2001:DB8:123::200/2001:DB8:123::100 inbound 1 2001:DB8:123::200/128 2001:DB8:123::100/128 any 0 0 0 0 protect true Marin-Lopez, et al. Expires February 6, 2020 [Page 81] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 true transport esp 2 12 out/trans/2001:DB8:123::100/2001:DB8:123::200 outbound 1 2001:DB8:123::100/128 2001:DB8:123::200/128 any 0 0 0 0 protect true true transport esp 2 12 Marin-Lopez, et al. Expires February 6, 2020 [Page 82] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 out/trans/2001:DB8:123::100/2001:DB8:123::200 1 34501 true 100 true 32 2001:DB8:123::100/128 2001:DB8:123::200/128 any 0 0 0 0 esp transport 12 01:23:45:67:89:AB:CE:DF 01:23:45:67:89:AB:CE:DF 2 01:23:45:67:89:AB:CE:DF in/trans/2001:DB8:123::200/2001:DB8:123::100 1 34502 true 100 Marin-Lopez, et al. Expires February 6, 2020 [Page 83] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 true 32 2001:DB8:123::200/128 2001:DB8:123::100/128 any 0 0 0 0 esp transport 12 01:23:45:67:89:AB:CE:DF 01:23:45:67:89:AB:CE:DF 2 01:23:45:67:89:AB:CE:DF 2000000 2000 120 1000000 1000 60 replace Marin-Lopez, et al. Expires February 6, 2020 [Page 84] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 Appendix F. Examples of notifications. Below we show several XML files that represent different types of notifications defined in the IKE-less YANG model, which are sent by the NSF to the Security Controller. The notifications happen in the IKE-less case. in/trans/2001:DB8:123::200/2001:DB8:123::100 true 1000000 1000 60 Figure 9: Example of sadb-expire notification. in/trans/2001:DB8:123::200/2001:DB8:123::100 2001:DB8:123::200/128 2001:DB8:123::100/128 any 0 0 0 0 Figure 10: Example of sadb-acquire notification. Marin-Lopez, et al. Expires February 6, 2020 [Page 85] Internet-Draft SDN-based IPsec Flow Protection Services August 2019 in/trans/2001:DB8:123::200/2001:DB8:123::100 Figure 11: Example of sadb-seq-overflow notification. 666 Figure 12: Example of sadb-bad-spi notification. Authors' Addresses 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 February 6, 2020 [Page 86]