Network Working Group S. Sivakumar Internet-Draft Cisco Systems Intended status: Standards Track M. Boucadair Expires: January 4, 2018 Orange S. Vinapamula Juniper Networks July 3, 2017 YANG Data Model for Network Address Translation (NAT) draft-sivakumar-yang-nat-07 Abstract For the sake of network automation and the need for programming NAT function in particular, a data model for configuring and managing the NAT device is essential. This document defines a YANG data model for the NAT function. Both the NAT44 and NAT64 are covered in this document. 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 http://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 January 4, 2018. Copyright Notice Copyright (c) 2017 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 (http://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 Sivakumar, et al. Expires January 4, 2018 [Page 1] Internet-Draft Yang Model for NAT July 2017 include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 2 2. Overview of the NAT YANG Data Model . . . . . . . . . . . . . 3 3. NAT YANG Module . . . . . . . . . . . . . . . . . . . . . . . 9 4. Sample Examples . . . . . . . . . . . . . . . . . . . . . . . 34 5. Security Considerations . . . . . . . . . . . . . . . . . . . 34 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 35 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 35 8.1. Normative References . . . . . . . . . . . . . . . . . . 35 8.2. Informative References . . . . . . . . . . . . . . . . . 36 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 37 1. Introduction This document defines a data model for Network Address Translation (NAT) using the YANG data modeling language [RFC6020]. Traditional NAT is defined in [RFC2663] and Carrier Grade NAT is defined in [RFC6888]. This document covers the NAT features in both documents. This document also covers the NAT64 as defined in [RFC6146]. This document assumes [RFC4787][RFC5382][RFC5508] are enabled by default. 1.1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. The usage of the term "NAT device" in this document refer to any NAT44 and NAT64 devices. This document uses the term "Session" as it is defined in [RFC2663] and the term BIB as it is defined in [RFC6146]. 1.2. Tree Diagrams The meaning of the symbols in these diagrams is as follows: o Brackets "[" and "]" enclose list keys. Sivakumar, et al. Expires January 4, 2018 [Page 2] Internet-Draft Yang Model for NAT July 2017 o Curly braces "{" and "}" contain names of optional features that make the corresponding node conditional. o Abbreviations before data node names: "rw" means configuration (read-write), "ro" state data (read-only). o Symbols after data node names: "?" means an optional node, "!" a container with presence, and "*" denotes a "list" or "leaf-list". o Parentheses enclose choice and case nodes, and case nodes are also marked with a colon (":"). o Ellipsis ("...") stands for contents of subtrees that are not shown. 2. Overview of the NAT YANG Data Model The NAT data model is designed to cover both configuration and state retrieval, nevertheless this document covers dynamic (implicit) mapping while PCP-related functionality to instruct dynamic explicit mapping is defined in [I-D.boucadair-pcp-yang]. In order to cover, in particular, both NAT64 and NAT44 flavors, the NAT mapping structure allows to include an IPv4 or IPv6 address as an internal IP address. Remaining fields are common to both NAT schemes. NPTv6 is also in scope [RFC6296]. This document assumes [RFC4787][RFC5382][RFC5508] are enabled by default. Also, the data model relies on the recommendations in [RFC6888] and [RFC7857]. A single NAT device can have multiple NAT instances; each responsible to service a group of internal hosts. This document does make any assumption how internal hosts are attached to a given NAT instance. The data model assumes that each NAT instance can: be enable/ disabled, be provisioned with a dedicated configuration data, and maintain its own mapping table. This data model assumes that blocks of IP global addresses can be provisioned to the NAT function. These blocks may be contiguous or non-contiguous [RFC6888]. A NAT function can either assign individual port numbers or port sets (e.g., [RFC7753]). Both features are supported in the YANG data model. Sivakumar, et al. Expires January 4, 2018 [Page 3] Internet-Draft Yang Model for NAT July 2017 To accommodate deployments where [RFC6302] is not enabled, this YANG model allows to instruct a NAT function to log the destination port number. The reader may refer to [I-D.ietf-behave-ipfix-nat-logging] which provides the templates to log the destination ports. This document does not cover the following functionalities: o Dynamic explicit mappings. o DSCP-related operations. o Deterministic NAT assignment scheme [RFC7422]. The tree structure of the NAT data model is provided below: module: ietf-nat +--rw nat-config | +--rw nat-instances | +--rw nat-instance* [id] | +--rw id uint32 | +--rw name? string | +--rw enable? boolean | +--rw external-ip-address-pool* [pool-id] | | +--rw pool-id uint32 | | +--rw external-ip-pool? inet:ipv4-prefix | +--rw subscriber-mask-v6? uint8 | +--rw subscriber-mask-v4* [sub-mask-id] | | +--rw sub-mask-id uint32 | | +--rw sub-mask inet:ipv4-prefix | +--rw paired-address-pooling? boolean | +--rw nat-mapping-type? enumeration | +--rw nat-filtering-type? enumeration | +--rw port-quota? uint16 | +--rw port-set | | +--rw port-set-enable? boolean | | +--rw port-set-size? uint16 | | +--rw port-set-timeout? uint32 | +--rw port-allocation-type? enumeration | +--rw address-roundrobin-enable? boolean | +--rw udp-timeout? uint32 | +--rw tcp-idle-timeout? uint32 | +--rw tcp-trans-open-timeout? uint32 | +--rw tcp-trans-close-timeout? uint32 | +--rw tcp-in-syn-timeout? uint32 | +--rw fragment-min-timeout? uint32 | +--rw icmp-timeout? uint32 | +--rw per-port-timeout* [port-number] | | +--rw port-number inet:port-number | | +--rw port-timeout inet:port-number | +--rw hold-down-timeout? uint32 Sivakumar, et al. Expires January 4, 2018 [Page 4] Internet-Draft Yang Model for NAT July 2017 | +--rw logging-info | | +--rw destination-address inet:ipv4-prefix | | +--rw destination-port inet:port-number | +--rw connection-limit | | +--rw limit-per-subscriber? uint32 | | +--rw limit-per-vrf? uint32 | | +--rw limit-per-subnet? inet:ipv4-prefix | | +--rw limit-per-instance uint32 | | +--rw limit-per-udp uint32 | | +--rw limit-per-tcp uint32 | | +--rw limit-per-icmp uint32 | +--rw mapping-limit | | +--rw limit-per-subscriber? uint32 | | +--rw limit-per-vrf? uint32 | | +--rw limit-per-subnet? inet:ipv4-prefix | | +--rw limit-per-instance uint32 | | +--rw limit-per-transport uint8 | +--rw ftp-alg-enable? boolean | +--rw dns-alg-enable? boolean | +--rw tftp-alg-enable? boolean | +--rw msrpc-alg-enable? boolean | +--rw netbios-alg-enable? boolean | +--rw rcmd-alg-enable? boolean | +--rw ldap-alg-enable? boolean | +--rw sip-alg-enable? boolean | +--rw rtsp-alg-enable? boolean | +--rw h323-alg-enable? boolean | +--rw all-algs-enable? boolean | +--rw notify-pool-usage | | +--rw pool-id? uint32 | | +--rw notify-pool-hi-threshold percent | | +--rw notify-pool-low-threshold? percent | +--rw nat64-prefixes* [nat64-prefix-id] | | +--rw nat64-prefix-id uint32 | | +--rw nat64-prefix? inet:ipv6-prefix | | +--rw destination-ipv4-prefix* [ipv4-prefix-id] | | +--rw ipv4-prefix-id uint32 | | +--rw ipv4-prefix? inet:ipv4-prefix | +--rw mapping-table | +--rw mapping-entry* [index] | +--rw index uint32 | +--rw type? enumeration | +--rw internal-src-address inet:ip-address | +--rw internal-src-port | | +--rw (port-type)? | | +--:(single-port-number) | | | +--rw single-port-number? inet:port-number | | +--:(port-range) Sivakumar, et al. Expires January 4, 2018 [Page 5] Internet-Draft Yang Model for NAT July 2017 | | +--rw start-port-number? inet:port-number | | +--rw end-port-number? inet:port-number | +--rw external-src-address inet:ipv4-address | +--rw external-src-port | | +--rw (port-type)? | | +--:(single-port-number) | | | +--rw single-port-number? inet:port-number | | +--:(port-range) | | +--rw start-port-number? inet:port-number | | +--rw end-port-number? inet:port-number | +--rw transport-protocol uint8 | +--rw internal-dst-address? inet:ipv4-prefix | +--rw internal-dst-port | | +--rw (port-type)? | | +--:(single-port-number) | | | +--rw single-port-number? inet:port-number | | +--:(port-range) | | +--rw start-port-number? inet:port-number | | +--rw end-port-number? inet:port-number | +--rw external-dst-address? inet:ipv4-address | +--rw external-dst-port | | +--rw (port-type)? | | +--:(single-port-number) | | | +--rw single-port-number? inet:port-number | | +--:(port-range) | | +--rw start-port-number? inet:port-number | | +--rw end-port-number? inet:port-number | +--rw lifetime uint32 +--ro nat-state +--ro nat-instances +--ro nat-instance* [id] +--ro id int32 +--ro nat-capabilities | +--ro nat44-support? boolean | +--ro nat64-support? boolean | +--ro nptv6-support? boolean | +--ro static-mapping-support? boolean | +--ro port-set-support? boolean | +--ro port-randomization-support? boolean | +--ro port-range-preservation-support? boolean | +--ro port-preservation-suport? boolean | +--ro port-parity-preservation-support? boolean | +--ro address-roundrobin-support? boolean | +--ro ftp-alg-support? boolean | +--ro dns-alg-support? boolean | +--ro tftp-support? boolean | +--ro msrpc-alg-support? boolean | +--ro netbios-alg-support? boolean Sivakumar, et al. Expires January 4, 2018 [Page 6] Internet-Draft Yang Model for NAT July 2017 | +--ro rcmd-alg-support? boolean | +--ro ldap-alg-support? boolean | +--ro sip-alg-support? boolean | +--ro rtsp-alg-support? boolean | +--ro h323-alg-support? boolean | +--ro paired-address-pooling-support? boolean | +--ro endpoint-independent-mapping-support? boolean | +--ro address-dependent-mapping-support? boolean | +--ro address-and-port-dependent-mapping-support? boolean | +--ro endpoint-independent-filtering-support? boolean | +--ro address-dependent-filtering? boolean | +--ro address-and-port-dependent-filtering? boolean +--ro nat-current-config | +--ro external-ip-address-pool* [pool-id] | | +--ro pool-id uint32 | | +--ro external-ip-pool? inet:ipv4-prefix | +--ro subscriber-mask-v6? uint8 | +--ro subscriber-mask-v4* [sub-mask-id] | | +--ro sub-mask-id uint32 | | +--ro sub-mask inet:ipv4-prefix | +--ro paired-address-pooling? boolean | +--ro nat-mapping-type? enumeration | +--ro nat-filtering-type? enumeration | +--ro port-quota? uint16 | +--ro port-set | | +--ro port-set-enable? boolean | | +--ro port-set-size? uint16 | | +--ro port-set-timeout? uint32 | +--ro port-allocation-type? enumeration | +--ro address-roundrobin-enable? boolean | +--ro udp-timeout? uint32 | +--ro tcp-idle-timeout? uint32 | +--ro tcp-trans-open-timeout? uint32 | +--ro tcp-trans-close-timeout? uint32 | +--ro tcp-in-syn-timeout? uint32 | +--ro fragment-min-timeout? uint32 | +--ro icmp-timeout? uint32 | +--ro per-port-timeout* [port-number] | | +--ro port-number inet:port-number | | +--ro port-timeout inet:port-number | +--ro hold-down-timeout? uint32 | +--ro logging-info | | +--ro destination-address inet:ipv4-prefix | | +--ro destination-port inet:port-number | +--ro connection-limit | | +--ro limit-per-subscriber? uint32 | | +--ro limit-per-vrf? uint32 | | +--ro limit-per-subnet? inet:ipv4-prefix Sivakumar, et al. Expires January 4, 2018 [Page 7] Internet-Draft Yang Model for NAT July 2017 | | +--ro limit-per-instance uint32 | | +--ro limit-per-udp uint32 | | +--ro limit-per-tcp uint32 | | +--ro limit-per-icmp uint32 | +--ro mapping-limit | | +--ro limit-per-subscriber? uint32 | | +--ro limit-per-vrf? uint32 | | +--ro limit-per-subnet? inet:ipv4-prefix | | +--ro limit-per-instance uint32 | | +--ro limit-per-transport uint8 | +--ro ftp-alg-enable? boolean | +--ro dns-alg-enable? boolean | +--ro tftp-alg-enable? boolean | +--ro msrpc-alg-enable? boolean | +--ro netbios-alg-enable? boolean | +--ro rcmd-alg-enable? boolean | +--ro ldap-alg-enable? boolean | +--ro sip-alg-enable? boolean | +--ro rtsp-alg-enable? boolean | +--ro h323-alg-enable? boolean | +--ro all-algs-enable? boolean | +--ro notify-pool-usage | | +--ro pool-id? uint32 | | +--ro notify-pool-hi-threshold percent | | +--ro notify-pool-low-threshold? percent | +--ro nat64-prefixes* [nat64-prefix-id] | +--ro nat64-prefix-id uint32 | +--ro nat64-prefix? inet:ipv6-prefix | +--ro destination-ipv4-prefix* [ipv4-prefix-id] | +--ro ipv4-prefix-id uint32 | +--ro ipv4-prefix? inet:ipv4-prefix +--ro mapping-table | +--ro mapping-entry* [index] | +--ro index uint32 | +--ro type? enumeration | +--ro internal-src-address inet:ip-address | +--ro internal-src-port | | +--ro (port-type)? | | +--:(single-port-number) | | | +--ro single-port-number? inet:port-number | | +--:(port-range) | | +--ro start-port-number? inet:port-number | | +--ro end-port-number? inet:port-number | +--ro external-src-address inet:ipv4-address | +--ro external-src-port | | +--ro (port-type)? | | +--:(single-port-number) | | | +--ro single-port-number? inet:port-number Sivakumar, et al. Expires January 4, 2018 [Page 8] Internet-Draft Yang Model for NAT July 2017 | | +--:(port-range) | | +--ro start-port-number? inet:port-number | | +--ro end-port-number? inet:port-number | +--ro transport-protocol uint8 | +--ro internal-dst-address? inet:ipv4-prefix | +--ro internal-dst-port | | +--ro (port-type)? | | +--:(single-port-number) | | | +--ro single-port-number? inet:port-number | | +--:(port-range) | | +--ro start-port-number? inet:port-number | | +--ro end-port-number? inet:port-number | +--ro external-dst-address? inet:ipv4-address | +--ro external-dst-port | | +--ro (port-type)? | | +--:(single-port-number) | | | +--ro single-port-number? inet:port-number | | +--:(port-range) | | +--ro start-port-number? inet:port-number | | +--ro end-port-number? inet:port-number | +--ro lifetime uint32 +--ro statistics +--ro total-mappings? uint32 +--ro total-tcp-mappings? uint32 +--ro total-udp-mappings? uint32 +--ro total-icmp-mappings? uint32 +--ro pool-stats +--ro pool-id? uint32 +--ro address-allocated? uint32 +--ro address-free? uint32 +--ro port-stats +--ro ports-allocated? uint32 +--ro ports-free? uint32 notifications: +---n nat-event +--ro id? -> /nat-state/nat-instances/nat-instance/id +--ro notify-pool-threshold percent 3. NAT YANG Module file "ietf-nat@2017-07-03.yang" module ietf-nat { namespace "urn:ietf:params:xml:ns:yang:ietf-nat"; //namespace to be assigned by IANA Sivakumar, et al. Expires January 4, 2018 [Page 9] Internet-Draft Yang Model for NAT July 2017 prefix "nat"; import ietf-inet-types { prefix "inet"; } organization "IETF NetMod Working Group"; contact "Senthil Sivakumar Mohamed Boucadair Suresh Vinapamula "; description "This module is a YANG module for NAT implementations (including both NAT44 and NAT64 flavors). Copyright (c) 2017 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Simplified BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX; see the RFC itself for full legal notices."; revision 2017-07-03 { description "Integrates comments from D. Wing and T. Zhou."; reference "-06"; } revision 2015-09-08 { description "Fixes few YANG errors."; reference "-02"; } revision 2015-09-07 { description "Completes the NAT64 model."; reference "01"; } revision 2015-08-29 { description "Initial version."; reference "00"; } typedef percent { Sivakumar, et al. Expires January 4, 2018 [Page 10] Internet-Draft Yang Model for NAT July 2017 type uint8 { range "0 .. 100"; } description "Percentage"; } /* * Grouping */ grouping timeouts { description "Configure values of various timeouts."; leaf udp-timeout { type uint32; default 300; description "UDP inactivity timeout."; } leaf tcp-idle-timeout { type uint32; default 7440; description "TCP Idle timeout, as per RFC 5382 should be no 2 hours and 4 minutes."; } leaf tcp-trans-open-timeout { type uint32; units "seconds"; default 240; description "The value of the transitory open connection idle-timeout. Section 2.1 of [RFC7857] clarifies that a NAT should provide different configurable parameters for configuring the open and closing idle timeouts. To accommodate deployments that consider a partially open timeout of 4 minutes as being excessive from a security standpoint, a NAT may allow the configured timeout to be less than 4 minutes. However, a minimum default transitory connection idle-timeout of 4 minutes is recommended."; Sivakumar, et al. Expires January 4, 2018 [Page 11] Internet-Draft Yang Model for NAT July 2017 } leaf tcp-trans-close-timeout { type uint32; units "seconds"; default 240; description "The value of the transitory close connection idle-timeout. Section 2.1 of [RFC7857] clarifies that a NAT should provide different configurable parameters for configuring the open and closing idle timeouts."; } leaf tcp-in-syn-timeout { type uint32; default 6; description "6 seconds, as defined in [RFC5382]."; } leaf fragment-min-timeout { type uint32; default 2; description "As long as the NAT has available resources, the NAT allows the fragments to arrive over fragment-min-timeout interval. The default value is inspired from RFC6146."; } leaf icmp-timeout { type uint32; default 60; description "60 seconds, as defined in [RFC5508]."; } list per-port-timeout { key port-number; description "Some NATs are configurable with short timeouts for some ports, e.g., as 10 seconds on port 53 (DNS) and NTP (123) and longer timeouts on other ports."; Sivakumar, et al. Expires January 4, 2018 [Page 12] Internet-Draft Yang Model for NAT July 2017 leaf port-number { type inet:port-number; description " A port number."; } leaf port-timeout { type inet:port-number; mandatory true; description "Timeout for this port"; } } leaf hold-down-timeout { type uint32; units "seconds"; default 120; description "Hold down timer. Ports in the hold down pool are not reassigned until this timer expires. The length of time and the maximum number of ports in this state must be configurable by the administrator [RFC6888]. This is necessary in order to prevent collisions between old and new mappings and sessions. It ensures that all established sessions are broken instead of redirected to a different peer. The default value is defined in REQ#8 from [RFC6888]."; } } // port numbers: single or port range grouping port-number { description "Individual port or a range of ports."; choice port-type { default single-port-number; description "Port type: single or port-range."; case single-port-number { leaf single-port-number { Sivakumar, et al. Expires January 4, 2018 [Page 13] Internet-Draft Yang Model for NAT July 2017 type inet:port-number; description "Used for single port numbers."; } } case port-range { leaf start-port-number { type inet:port-number; description "Begining of the port range."; } leaf end-port-number { type inet:port-number; description "End of the port range."; } } } } grouping mapping-entry { description "NAT mapping entry."; leaf index { type uint32; description "A unique identifier of a mapping entry."; } leaf type { type enumeration { enum "static" { description "The mapping entry is manually configured."; } enum "dynamic" { description "This mapping is created by an outgoing packet."; } } description "Indicates the type of a mapping entry. E.g., a mapping can be: static or dynamic"; Sivakumar, et al. Expires January 4, 2018 [Page 14] Internet-Draft Yang Model for NAT July 2017 } leaf internal-src-address { type inet:ip-address; mandatory true; description "Corresponds to the source IPv4/IPv6 address of the IPv4 packet"; } container internal-src-port { description "Corresponds to the source port of the IPv4 packet."; uses port-number; } leaf external-src-address { type inet:ipv4-address; mandatory true; description "External IPv4 address assigned by NAT"; } container external-src-port { description "External source port number assigned by NAT."; uses port-number; } leaf transport-protocol { type uint8; mandatory true; description "Upper-layer protocol associated with this mapping. Values are taken from the IANA protocol registry. For example, this field contains 6 (TCP) for a TCP mapping or 17 (UDP) for a UDP mapping."; } leaf internal-dst-address { type inet:ipv4-prefix; description "Corresponds to the destination IPv4 address of the IPv4 packet, for example, some NAT implementation support translating both source and destination address and ports referred to as Twice NAT"; Sivakumar, et al. Expires January 4, 2018 [Page 15] Internet-Draft Yang Model for NAT July 2017 } container internal-dst-port { description "Corresponds to the destination port of the IPv4 packet."; uses port-number; } leaf external-dst-address { type inet:ipv4-address; description "External destination IPv4 address"; } container external-dst-port { description "External source port number."; uses port-number; } leaf lifetime { type uint32; mandatory true; description "Lifetime of the mapping. Tracks the connection that is fully-formed (e.g., 3WHS TCP is completd."; } } grouping nat-parameters { description "NAT parameters for a given instance"; list external-ip-address-pool { key pool-id; description "Pool of external IP addresses used to service internal hosts. Both contiguous and non-contiguous pools can be configured for NAT."; leaf pool-id { type uint32; description Sivakumar, et al. Expires January 4, 2018 [Page 16] Internet-Draft Yang Model for NAT July 2017 "An identifier of the address pool."; } leaf external-ip-pool { type inet:ipv4-prefix; description "An IPv4 prefix used for NAT purposes."; } } leaf subscriber-mask-v6 { type uint8 { range "0 .. 128"; } description "The subscriber-mask is an integer that indicates the length of significant bits to be applied on the source IP address (internal side) to unambiguously identify a CPE. Subscriber-mask is a system-wide configuration parameter that is used to enforce generic per-subscriberpolicies (e.g., port-quota). The enforcement of these generic policies does not require the configuration of every subscriber's prefix. Example: suppose the 2001:db8:100:100::/56 prefix is assigned to a NAT64 serviced CPE. Suppose also that 2001:db8:100:100::1 is the IPv6 address used by the client that resides in that CPE. When the NAT64 receives a packet from this client, it applies the subscriber-mask (e.g., 56) on the source IPv6 address to compute the associated prefix for this client (2001:db8:100:100::/56). Then, the NAT64 enforces policies based on that prefix (2001:db8:100:100::/56), not on the exact source IPv6 address."; } list subscriber-mask-v4 { key sub-mask-id; description Sivakumar, et al. Expires January 4, 2018 [Page 17] Internet-Draft Yang Model for NAT July 2017 "IPv4 subscriber mask."; leaf sub-mask-id { type uint32; description "An identifier of the subscriber masks."; } leaf sub-mask { type inet:ipv4-prefix; mandatory true; description "The IP address subnets that matches should be translated. E.g., If the private realms that are to be translated by NAT would be 192.0.2.0/24"; } } leaf paired-address-pooling { type boolean; default true; description "Paired address pooling is indicating to NAT that all the flows from an internal IP address must be assigned the same external address. This is defined in RFC 4007."; } leaf nat-mapping-type { type enumeration { enum "eim" { description "endpoint-independent-mapping. Refer section 4 of RFC 4787."; } enum "adm" { description "address-dependent-mapping. Refer section 4 of RFC 4787."; } enum "edm" { description "address-and-port-dependent-mapping. Refer section 4 of RFC 4787."; } } Sivakumar, et al. Expires January 4, 2018 [Page 18] Internet-Draft Yang Model for NAT July 2017 description "Indicates the type of a NAT mapping."; } leaf nat-filtering-type { type enumeration { enum "eif" { description "endpoint-independent- filtering. Refer section 5 of RFC 4787."; } enum "adf" { description "address-dependent- filtering. Refer section 5 of RFC 4787."; } enum "edf" { description "address-and-port-dependent- filtering. Refer section 5 of RFC 4787."; } } description "Indicates the type of a NAT filtering."; } leaf port-quota { type uint16; description "Configures a port quota to be assigned per subscriber. It corresponds to the maximum number of ports to be used by a subscriber."; } container port-set { description "Manages port-set assignments."; leaf port-set-enable { type boolean; description "Enable/Disable port set assignment."; } leaf port-set-size { type uint16; description Sivakumar, et al. Expires January 4, 2018 [Page 19] Internet-Draft Yang Model for NAT July 2017 "Indicates the size of assigned port sets."; } leaf port-set-timeout { type uint32; description "Inactivty timeout for port sets."; } } leaf port-allocation-type { type enumeration { enum "random" { description "Port port randomization."; } enum "port-preservation" { description "Indicates whether the PCP server should preserve the internal port number."; } enum "port-range-preservation" { description "Indicates whether the NAT device should preserve the internal port range."; } enum "port-parity-preservation" { description "Indicates whether the PCP server should preserve the port parity of the internal port number."; } } description "Indicates the type of a NAT mapping."; } leaf address-roundrobin-enable { type boolean; description "Enable/disable address allocation round robin."; } Sivakumar, et al. Expires January 4, 2018 [Page 20] Internet-Draft Yang Model for NAT July 2017 uses timeouts; container logging-info { description "Information about Logging NAT events"; leaf destination-address { type inet:ipv4-prefix; mandatory true; description "Address of the collector that receives the logs"; } leaf destination-port { type inet:port-number; mandatory true; description "Destination port of the collector."; } } container connection-limit { description "Information on the config parameters that rate limit the translations based on various criteria"; leaf limit-per-subscriber { type uint32; description "Maximum number of NAT mappings per subscriber."; } leaf limit-per-vrf { type uint32; description "Maximum number of NAT mappings per VLAN/VRF."; } leaf limit-per-subnet { type inet:ipv4-prefix; description "Maximum number of NAT mappings per subnet."; } leaf limit-per-instance { type uint32; mandatory true; description Sivakumar, et al. Expires January 4, 2018 [Page 21] Internet-Draft Yang Model for NAT July 2017 "Maximum number of NAT mappings per instance."; } leaf limit-per-udp { type uint32; mandatory true; description "Maximum number of UDP NAT mappings per instance."; } leaf limit-per-tcp { type uint32; mandatory true; description "Maximum number of TCP NAT mappings per instance."; } leaf limit-per-icmp { type uint32; mandatory true; description "Maximum number of ICMP NAT mappings per instance."; } } container mapping-limit { description "Information on the config parameters that rate limit the mappings based on various criteria"; leaf limit-per-subscriber { type uint32; description "Maximum number of NAT mappings per subscriber."; } leaf limit-per-vrf { type uint32; description "Maximum number of NAT mappings per VLAN/VRF."; } leaf limit-per-subnet { type inet:ipv4-prefix; description "Maximum number of NAT mappings per Sivakumar, et al. Expires January 4, 2018 [Page 22] Internet-Draft Yang Model for NAT July 2017 subnet."; } leaf limit-per-instance { type uint32; mandatory true; description "Maximum number of NAT mappings per instance."; } leaf limit-per-transport { type uint32; mandatory true; description "Maximum number of NAT mappings per transport protocol."; } } leaf ftp-alg-enable { type boolean; description "Enable/Disable FTP ALG"; } leaf dns-alg-enable { type boolean; description "Enable/Disable DNSALG"; } leaf tftp-alg-enable { type boolean; description "Enable/Disable TFTP ALG"; } leaf msrpc-alg-enable { type boolean; description "Enable/Disable MS-RPC ALG"; } leaf netbios-alg-enable { type boolean; description "Enable/Disable NetBIOS ALG"; } Sivakumar, et al. Expires January 4, 2018 [Page 23] Internet-Draft Yang Model for NAT July 2017 leaf rcmd-alg-enable { type boolean; description "Enable/Disable rcmd ALG"; } leaf ldap-alg-enable { type boolean; description "Enable/Disable LDAP ALG"; } leaf sip-alg-enable { type boolean; description "Enable/Disable SIP ALG"; } leaf rtsp-alg-enable { type boolean; description "Enable/Disable RTSP ALG"; } leaf h323-alg-enable { type boolean; description "Enable/Disable H323 ALG"; } leaf all-algs-enable { type boolean; description "Enable/Disable all the ALGs"; } container notify-pool-usage { description "Notification of Pool usage when certain criteria is met"; leaf pool-id { type uint32; description "Pool-ID for which the notification criteria is defined"; } Sivakumar, et al. Expires January 4, 2018 [Page 24] Internet-Draft Yang Model for NAT July 2017 leaf notify-pool-hi-threshold { type percent; mandatory true; description "Notification must be generated when the defined high threshold is reached. For example, if a notification is required when the pool utilization reaches 90%, this configuration parameter must be set to 90%"; } leaf notify-pool-low-threshold { type percent; description "Notification must be generated when the defined low threshold is reached. For example, if a notification is required when the pool utilization reaches below 10%, this configuration parameter must be set to 10%"; } } list nat64-prefixes { key nat64-prefix-id; description "Provides one or a list of NAT64 prefixes With or without a list of destination IPv4 prefixes. Destination-based Pref64::/n is discussed in Section 5.1 of [RFC7050]). For example: 192.0.2.0/24 is mapped to 2001:db8:122:300::/56. 198.51.100.0/24 is mapped to 2001:db8:122::/48."; leaf nat64-prefix-id { type uint32; description "An identifier of the NAT64 prefix."; } leaf nat64-prefix { type inet:ipv6-prefix; default "64:ff9b::/96"; description "A NAT64 prefix. Can be NSP or WKP [RFC6052]."; } Sivakumar, et al. Expires January 4, 2018 [Page 25] Internet-Draft Yang Model for NAT July 2017 list destination-ipv4-prefix { key ipv4-prefix-id; description "An IPv4 prefix/address."; leaf ipv4-prefix-id { type uint32; description "An identifier of the IPv4 prefix/address."; } leaf ipv4-prefix { type inet:ipv4-prefix; description "An IPv4 address/prefix. "; } } } } //nat-parameters group container nat-config { description "NAT"; container nat-instances { description "nat instances"; list nat-instance { key "id"; description "A NAT instance."; leaf id { type uint32; description "NAT instance identifier [RFC7659]."; } leaf name { type string; description "A name associated with the NAT instance."; } Sivakumar, et al. Expires January 4, 2018 [Page 26] Internet-Draft Yang Model for NAT July 2017 leaf enable { type boolean; description "Status of the the NAT instance."; } uses nat-parameters; container mapping-table { description "NAT dynamic mapping table used to track sessions"; list mapping-entry { key "index"; description "NAT mapping entry."; uses mapping-entry; } } } } } /* * NAT State */ container nat-state { config false; description "nat-state"; container nat-instances { description "nat instances"; list nat-instance { key "id"; description "nat instance"; leaf id { type int32; description Sivakumar, et al. Expires January 4, 2018 [Page 27] Internet-Draft Yang Model for NAT July 2017 "The identifier of the nat instance."; } container nat-capabilities { description "NAT Capabilities"; leaf nat44-support { type boolean; description "Indicates NAT44 support"; } leaf nat64-support { type boolean; description "Indicates NAT64 support"; } leaf nptv6-support { type boolean; description "Indicates NPTv6 support"; } leaf static-mapping-support { type boolean; description "Indicates whether static mappings are supported."; } leaf port-set-support { type boolean; description "Indicates port set assignment support "; } leaf port-randomization-support { type boolean; description "Indicates whether port randomization is supported."; } leaf port-range-preservation-support { type boolean; Sivakumar, et al. Expires January 4, 2018 [Page 28] Internet-Draft Yang Model for NAT July 2017 description "Indicates whether port range preservation is supported."; } leaf port-preservation-suport { type boolean; description "Indicates whether port preservation is supported."; } leaf port-parity-preservation-support { type boolean; description "Indicates whether port parity preservation is supported."; } leaf address-roundrobin-support { type boolean; description "Indicates whether address allocation round robin is supported."; } leaf ftp-alg-support { type boolean; description "Indicates whether FTP ALG is supported"; } leaf dns-alg-support { type boolean; description "Indicates whether DNSALG is supported"; } leaf tftp-support { type boolean; description "Indicates whether TFTP ALG is supported"; } leaf msrpc-alg-support { type boolean; description "Indicates whether MS-RPC ALG is supported"; Sivakumar, et al. Expires January 4, 2018 [Page 29] Internet-Draft Yang Model for NAT July 2017 } leaf netbios-alg-support { type boolean; description "Indicates whether NetBIOS ALG is supported"; } leaf rcmd-alg-support { type boolean; description "Indicates whether rcmd ALG is supported"; } leaf ldap-alg-support { type boolean; description "Indicates whether LDAP ALG is supported"; } leaf sip-alg-support { type boolean; description "Indicates whether SIP ALG is supported"; } leaf rtsp-alg-support { type boolean; description "Indicates whether RTSP ALG is supported"; } leaf h323-alg-support { type boolean; description "Indicates whether H323 ALG is supported"; } leaf paired-address-pooling-support { type boolean; description "Indicates whether paired-address-pooling is supported"; } leaf endpoint-independent-mapping-support { type boolean; description Sivakumar, et al. Expires January 4, 2018 [Page 30] Internet-Draft Yang Model for NAT July 2017 "Indicates whether endpoint-independent-mapping in Section 4 of RFC 4787 is supported."; } leaf address-dependent-mapping-support { type boolean; description "Indicates whether endpoint-independent-mapping in Section 4 of RFC 4787 is supported."; } leaf address-and-port-dependent-mapping-support { type boolean; description "Indicates whether endpoint-independent-mapping in section 4 of RFC 4787 is supported."; } leaf endpoint-independent-filtering-support { type boolean; description "Indicates whether endpoint-independent-mapping in section 5 of RFC 4787 is supported."; } leaf address-dependent-filtering { type boolean; description "Indicates whether endpoint-independent-mapping in section 5 of RFC 4787 is supported."; } leaf address-and-port-dependent-filtering { type boolean; description "Indicates whether endpoint-independent-mapping in section 5 of RFC 4787 is supported."; } } container nat-current-config { description "current config"; uses nat-parameters; } Sivakumar, et al. Expires January 4, 2018 [Page 31] Internet-Draft Yang Model for NAT July 2017 container mapping-table { description "Mapping table"; list mapping-entry { key "index"; description "mapping entry"; uses mapping-entry; } } container statistics { description "Statistics related to the NAT instance"; leaf total-mappings { type uint32; description "Total number of NAT Mappings present at the time. This includes all the static and dynamic mappings"; } leaf total-tcp-mappings { type uint32; description "Total number of TCP Mappings present at the time."; } leaf total-udp-mappings { type uint32; description "Total number of UDP Mappings present at the time."; } leaf total-icmp-mappings { type uint32; description "Total number of ICMP Mappings present at the time."; } container pool-stats { description "Statistics related to Pool usage"; leaf pool-id { type uint32; description "Unique Identifier that represents a pool"; Sivakumar, et al. Expires January 4, 2018 [Page 32] Internet-Draft Yang Model for NAT July 2017 } leaf address-allocated { type uint32; description "Number of allocated addresses in the pool"; } leaf address-free { type uint32; description "Number of free addresses in the pool.The sum of free addresses and allocated addresses are the total addresses in the pool"; } container port-stats { description "Statistics related to port usage."; leaf ports-allocated { type uint32; description "Number of allocated ports in the pool"; } leaf ports-free { type uint32; description "Number of free addresses in the pool"; } } } } //statistics } //nat-instance } //nat-instances } //nat-state /* * Notifications */ notification nat-event { description "Notifications must be generated when the defined high/low threshold is reached. Related configuration parameters must be provided to trigger Sivakumar, et al. Expires January 4, 2018 [Page 33] Internet-Draft Yang Model for NAT July 2017 the notifications."; leaf id { type leafref { path "/nat-state/nat-instances/" + "nat-instance/id"; } description "NAT instance ID."; } leaf notify-pool-threshold { type percent; mandatory true; description "A treshhold has been fired."; } } } //module nat 4. Sample Examples TBC 5. Security Considerations The YANG module defined in this memo is designed to be accessed via the NETCONF protocol [RFC6241]. The lowest NETCONF layer is the secure transport layer and the support of SSH is mandatory to implement secure transport [RFC6242]. The NETCONF access control model [RFC6536] provides means to restrict access for particular NETCONF users to a pre-configured subset of all available NETCONF protocol operations and contents. All data nodes defined in the YANG module which can be created, modified and deleted (i.e., config true, which is the default). These data nodes are considered sensitive. Write operations (e.g., edit-config) applied to these data nodes without proper protection can negatively affect network operations. 6. IANA Considerations This document requests IANA to register the following URI in the "IETF XML Registry" [RFC3688]: Sivakumar, et al. Expires January 4, 2018 [Page 34] Internet-Draft Yang Model for NAT July 2017 URI: urn:ietf:params:xml:ns:yang:ietf-nat Registrant Contact: The IESG. XML: N/A; the requested URI is an XML namespace. This document requests IANA to register the following YANG module in the "YANG Module Names" registry [RFC6020]. name: ietf-nat namespace: urn:ietf:params:xml:ns:yang:ietf-nat prefix: nat reference: RFC XXXX 7. Acknowledgements Many thanks to Dan Wing and Tianran Zhou for the review. 8. References 8.1. 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, . [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [RFC4787] Audet, F., Ed. and C. Jennings, "Network Address Translation (NAT) Behavioral Requirements for Unicast UDP", BCP 127, RFC 4787, DOI 10.17487/RFC4787, January 2007, . [RFC5382] Guha, S., Ed., Biswas, K., Ford, B., Sivakumar, S., and P. Srisuresh, "NAT Behavioral Requirements for TCP", BCP 142, RFC 5382, DOI 10.17487/RFC5382, October 2008, . [RFC5508] Srisuresh, P., Ford, B., Sivakumar, S., and S. Guha, "NAT Behavioral Requirements for ICMP", BCP 148, RFC 5508, DOI 10.17487/RFC5508, April 2009, . Sivakumar, et al. Expires January 4, 2018 [Page 35] Internet-Draft Yang Model for NAT July 2017 [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful NAT64: Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146, April 2011, . [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, . [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, DOI 10.17487/RFC6536, March 2012, . [RFC6888] Perreault, S., Ed., Yamagata, I., Miyakawa, S., Nakagawa, A., and H. Ashida, "Common Requirements for Carrier-Grade NATs (CGNs)", BCP 127, RFC 6888, DOI 10.17487/RFC6888, April 2013, . [RFC7857] Penno, R., Perreault, S., Boucadair, M., Ed., Sivakumar, S., and K. Naito, "Updates to Network Address Translation (NAT) Behavioral Requirements", BCP 127, RFC 7857, DOI 10.17487/RFC7857, April 2016, . 8.2. Informative References [I-D.boucadair-pcp-yang] Boucadair, M., Jacquenet, C., Sivakumar, S., and S. Vinapamula, "YANG Data Models for the Port Control Protocol (PCP)", draft-boucadair-pcp-yang-04 (work in progress), May 2017. [I-D.ietf-behave-ipfix-nat-logging] Sivakumar, S. and R. Penno, "IPFIX Information Elements for logging NAT Events", draft-ietf-behave-ipfix-nat- logging-13 (work in progress), January 2017. Sivakumar, et al. Expires January 4, 2018 [Page 36] Internet-Draft Yang Model for NAT July 2017 [RFC2663] Srisuresh, P. and M. Holdrege, "IP Network Address Translator (NAT) Terminology and Considerations", RFC 2663, DOI 10.17487/RFC2663, August 1999, . [RFC6296] Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix Translation", RFC 6296, DOI 10.17487/RFC6296, June 2011, . [RFC6302] Durand, A., Gashinsky, I., Lee, D., and S. Sheppard, "Logging Recommendations for Internet-Facing Servers", BCP 162, RFC 6302, DOI 10.17487/RFC6302, June 2011, . [RFC7422] Donley, C., Grundemann, C., Sarawat, V., Sundaresan, K., and O. Vautrin, "Deterministic Address Mapping to Reduce Logging in Carrier-Grade NAT Deployments", RFC 7422, DOI 10.17487/RFC7422, December 2014, . [RFC7659] Perreault, S., Tsou, T., Sivakumar, S., and T. Taylor, "Definitions of Managed Objects for Network Address Translators (NATs)", RFC 7659, DOI 10.17487/RFC7659, October 2015, . [RFC7753] Sun, Q., Boucadair, M., Sivakumar, S., Zhou, C., Tsou, T., and S. Perreault, "Port Control Protocol (PCP) Extension for Port-Set Allocation", RFC 7753, DOI 10.17487/RFC7753, February 2016, . Authors' Addresses Senthil Sivakumar Cisco Systems 7100-8 Kit Creek Road Research Triangle Park, North Carolina 27709 USA Phone: +1 919 392 5158 Email: ssenthil@cisco.com Mohamed Boucadair Orange Rennes 35000 France Email: mohamed.boucadair@orange.com Sivakumar, et al. Expires January 4, 2018 [Page 37] Internet-Draft Yang Model for NAT July 2017 Suresh Vinapamula Juniper Networks 1133 Innovation Way Sunnyvale 94089 USA Sivakumar, et al. Expires January 4, 2018 [Page 38]