Network Working Group M. Bjorklund Internet-Draft Tail-f Systems Intended status: Standards Track September 5, 2012 Expires: March 9, 2013 A YANG Data Model for IP Configuration draft-ietf-netmod-ip-cfg-06 Abstract This document defines a YANG data model for configuration of IP implementations. 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 March 9, 2013. Copyright Notice Copyright (c) 2012 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 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. Bjorklund Expires March 9, 2013 [Page 1] Internet-Draft YANG IP Configuration September 2012 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 2. IP Data Model . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Relationship to IP-MIB . . . . . . . . . . . . . . . . . . . . 6 4. IP configuration YANG Module . . . . . . . . . . . . . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14 6. Security Considerations . . . . . . . . . . . . . . . . . . . 15 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 16 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17 8.1. Normative References . . . . . . . . . . . . . . . . . . . 17 8.2. Informative References . . . . . . . . . . . . . . . . . . 17 Appendix A. Example: NETCONF reply . . . . . . . . . . . . 19 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 20 Bjorklund Expires March 9, 2013 [Page 2] Internet-Draft YANG IP Configuration September 2012 1. Introduction This document defines a YANG [RFC6020] data model for configuration of IP implementations. The initial version of this data model focuses on configuration parameters for interfaces. Future revisions of this data model might add other kinds of IP configuration parameters. Configuration parameters to control IP routing are defined in [I-D.ietf-netmod-routing-cfg]. 1.1. Terminology The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14, [RFC2119]. The following terms are defined in [RFC6241] and are not redefined here: o client o server The following terms are defined in [RFC6020] and are not redefined here: o augment o data model o data node Bjorklund Expires March 9, 2013 [Page 3] Internet-Draft YANG IP Configuration September 2012 2. IP Data Model The module "ietf-ip" augments the "interface" list defined in the "ietf-interfaces" module [I-D.ietf-netmod-interfaces-cfg] with the following data nodes, where square brackets are used to enclose a list's keys, and "?" means that the node is optional. Choice and case nodes are enclosed in parenthesis, and a case node is marked with a colon (":"). +--rw if:interfaces +--rw if:interface [name] ... +--rw ipv4? | +--rw enabled? boolean | +--rw ip-forwarding? boolean | +--rw address [ip] | | +--rw ip inet:ipv4-address | | +--rw (subnet)? | | +--:(prefix-length) | | | +--rw ip:prefix-length? uint8 | | +--:(netmask) | | +--rw ip:netmask? inet:ipv4-address | +--rw neighbor [ip] | +--rw ip inet:ipv4-address | +--rw phys-address? yang:phys-address +--rw ipv6? +--rw enabled? boolean +--rw ip-forwarding? boolean +--rw address [ip] | +--rw ip inet:ipv6-address | +--rw prefix-length? uint8 +--rw neighbor [ip] | +--rw ip inet:ipv6-address | +--rw phys-address? yang:phys-address +--rw dup-addr-detect-transmits? uint32 +--rw autoconf +--rw create-global-addresses? boolean +--rw create-temporary-addresses? boolean +--rw temporary-valid-lifetime? uint32 +--rw temporary-preferred-lifetime? uint32 The data model defines two containers, "ipv4" and "ipv6", representing the IPv4 and IPv6 address families. In each container, there is a leaf "enabled" that controls if the address family is enabled on that interface, and a leaf "ip-forwarding" that controls if ip packet forwarding for the address family is enabled on the interface. In each container, there is also a list of manually configured addresses, and a list of manually configured mappings from Bjorklund Expires March 9, 2013 [Page 4] Internet-Draft YANG IP Configuration September 2012 ip addresses to physical addresses. Bjorklund Expires March 9, 2013 [Page 5] Internet-Draft YANG IP Configuration September 2012 3. Relationship to IP-MIB If the device implements IP-MIB [RFC4293], each entry in the "ipv4/ address" and "ipv6/address" lists is mapped to one ipAddressEntry, where the ipAddressIfIndex refers to the interface where the "address" entry is configured. The IP-MIB defines objects to control IPv6 Router Advertisement. The corresponding YANG data nodes are defined in [I-D.ietf-netmod-routing-cfg]. The entries in "ipv4/neighbor" and "ipv6/neighbor" are mapped to ipNetToPhysicalTable. The object ipAddressStatus is writable in the IP-MIB but does not represent configuration, and is thus not mapped to the YANG module. The following table lists the YANG data nodes with corresponding objects in the IP-MIB. +--------------------+-----------------------------------+ | YANG data node | IP-MIB object | +--------------------+-----------------------------------+ | ipv4/enabled | ipv4InterfaceEnableStatus | | ipv4/address | ipAddressEntry | | ipv4/address/ip | ipAddressAddrType / ipAddressAddr | | ipv4/neighbor | ipNetToPhysicalTable | | ipv6/enabled | ipv6InterfaceEnableStatus | | ipv6/ip-forwarding | ipv6InterfaceForwarding | | ipv6/address | ipAddressEntry | | ipv6/address/ip | ipAddressAddrType / ipAddressAddr | | ipv6/neighbor | ipNetToPhysicalTable | +--------------------+-----------------------------------+ Mapping of YANG data nodes to IP-MIB objects Bjorklund Expires March 9, 2013 [Page 6] Internet-Draft YANG IP Configuration September 2012 4. IP configuration YANG Module This module imports typedefs from [RFC6021] and [I-D.ietf-netmod-interfaces-cfg], and references [RFC0826], [RFC4861], [RFC4862], and [RFC4941]. RFC Ed.: update the date below with the date of RFC publication and remove this note. file "ietf-ip@2012-09-05.yang" module ietf-ip { namespace "urn:ietf:params:xml:ns:yang:ietf-ip"; prefix ip; import ietf-interfaces { prefix if; } import ietf-inet-types { prefix inet; } import ietf-yang-types { prefix yang; } organization "IETF NETMOD (NETCONF Data Modeling Language) Working Group"; contact "WG Web: WG List: WG Chair: David Kessens WG Chair: Juergen Schoenwaelder Editor: Martin Bjorklund "; description "This module contains a collection of YANG definitions for configuring IP implementations. Copyright (c) 2012 IETF Trust and the persons identified as authors of the code. All rights reserved. Bjorklund Expires March 9, 2013 [Page 7] Internet-Draft YANG IP Configuration September 2012 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."; // RFC Ed.: replace XXXX with actual RFC number and remove this // note. // RFC Ed.: update the date below with the date of RFC publication // and remove this note. revision 2012-09-05 { description "Initial revision."; reference "RFC XXXX: A YANG Data Model for IP Configuration"; } /* Features */ feature ipv4-non-contiguous-netmasks { description "Indicates support for configuring non-contiguous subnet masks."; } feature ipv6-privacy-autoconf { description "Indicates support for Privacy Extensions for Stateless Address Autoconfiguration in IPv6."; reference "RFC 4941: Privacy Extensions for Stateless Address Autoconfiguration in IPv6"; } /* Data nodes */ augment "/if:interfaces/if:interface" { description "Parameters for configuring IP on interfaces. If an interface is not capable of running IP, the server must not allow the client to configure these parameters."; Bjorklund Expires March 9, 2013 [Page 8] Internet-Draft YANG IP Configuration September 2012 container ipv4 { presence "Configure IPv4 on this interface."; description "Parameters for the IPv4 address family."; leaf enabled { type boolean; default true; description "Controls if IPv4 is enabled or disabled on this interface."; } leaf ip-forwarding { type boolean; default false; description "Controls if IPv4 packet forwarding is enabled or disabled on this interface."; } list address { key "ip"; description "The list of IPv4 addresses on the interface."; leaf ip { type inet:ipv4-address; description "The IPv4 address on the interface."; } choice subnet { default prefix-length; description "The subnet can be specified as a prefix-length, or, if the server supports non-contiguous netmasks, as a netmask. The default subnet is a prefix-length of 32."; leaf prefix-length { type uint8 { range "0..32"; } default 32; description "The length of the subnet prefix."; } leaf netmask { if-feature ipv4-non-contiguous-netmasks; type inet:ipv4-address; Bjorklund Expires March 9, 2013 [Page 9] Internet-Draft YANG IP Configuration September 2012 description "The subnet specified as a netmask."; } } } list neighbor { key "ip"; description "A list of mappings from IPv4 addresses to physical addresses. Entries in this list are used as static entries in the ARP cache."; reference "RFC 826: An Ethernet Address Resolution Protocol"; leaf ip { type inet:ipv4-address; description "The IPv4 address of a neighbor node."; } leaf phys-address { type yang:phys-address; description "The physical level address of the neihgbor node."; } } } container ipv6 { presence "Configure IPv6 on this interface."; description "Parameters for the IPv6 address family."; leaf enabled { type boolean; default true; description "Controls if IPv6 is enabled or disabled on this interface."; } leaf ip-forwarding { type boolean; default false; description "Controls if IPv6 packet forwarding is enabled or disabled on this interface."; reference Bjorklund Expires March 9, 2013 [Page 10] Internet-Draft YANG IP Configuration September 2012 "RFC 4861: Neighbor Discovery for IP version 6 (IPv6) Section 6.2.1, IsRouter"; } list address { key "ip"; description "The list of IPv6 addresses on the interface."; leaf ip { type inet:ipv6-address; description "The IPv6 address on the interface."; } leaf prefix-length { type uint8 { range "0..128"; } default 128; description "The length of the subnet prefix."; } } list neighbor { key "ip"; description "A list of mappings from IPv6 addresses to physical addresses. Entries in this list are used as static entries in the Neighbor Cache."; reference "RFC 4861: Neighbor Discovery for IP version 6 (IPv6)"; leaf ip { type inet:ipv6-address; description "The IPv6 address of a neighbor node."; } leaf phys-address { type yang:phys-address; description "The physical level address of the neighbor node."; } } leaf dup-addr-detect-transmits { type uint32; default 1; description Bjorklund Expires March 9, 2013 [Page 11] Internet-Draft YANG IP Configuration September 2012 "The number of consecutive Neighbor Solicitation messages sent while performing Duplicate Address Detection on a tentative address. A value of zero indicates that Duplicate Address Detection is not performed on tentative addresses. A value of one indicates a single transmission with no follow-up retransmissions."; reference "RFC 4862: IPv6 Stateless Address Autoconfiguration"; } container autoconf { description "Parameters to control the autoconfiguration of IPv6 addresses, as described in RFC 4862."; reference "RFC 4862: IPv6 Stateless Address Autoconfiguration"; leaf create-global-addresses { type boolean; default true; description "If enabled, the host creates global addresses as described in section 5.5 of RFC 4862."; reference "RFC 4862: IPv6 Stateless Address Autoconfiguration"; } leaf create-temporary-addresses { if-feature ipv6-privacy-autoconf; type boolean; default false; description "If enabled, the host creates temporary addresses as described in RFC 4941."; reference "RFC 4941: Privacy Extensions for Stateless Address Autoconfiguration in IPv6"; } leaf temporary-valid-lifetime { if-feature ipv6-privacy-autoconf; type uint32; units "seconds"; default 604800; description "The time period during which the temporary address is valid."; reference "RFC 4941: Privacy Extensions for Stateless Address Autoconfiguration in IPv6 - TEMP_VALID_LIFETIME"; Bjorklund Expires March 9, 2013 [Page 12] Internet-Draft YANG IP Configuration September 2012 } leaf temporary-preferred-lifetime { if-feature ipv6-privacy-autoconf; type uint32; units "seconds"; default 86400; description "The time period during which the temporary address is preferred."; reference "RFC 4941: Privacy Extensions for Stateless Address Autoconfiguration in IPv6 - TEMP_PREFERED_LIFETIME"; } } } } } Bjorklund Expires March 9, 2013 [Page 13] Internet-Draft YANG IP Configuration September 2012 5. IANA Considerations This document registers a URI in the IETF XML registry [RFC3688]. Following the format in RFC 3688, the following registration is requested to be made. URI: urn:ietf:params:xml:ns:yang:ietf-ip Registrant Contact: The NETMOD WG of the IETF. XML: N/A, the requested URI is an XML namespace. This document registers a YANG module in the YANG Module Names registry [RFC6020]. name: ietf-ip namespace: urn:ietf:params:xml:ns:yang:ietf-ip prefix: ip reference: RFC XXXX Bjorklund Expires March 9, 2013 [Page 14] Internet-Draft YANG IP Configuration September 2012 6. 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 mandatory-to-implement secure transport is SSH [RFC6242]. There are a number of data nodes defined in the YANG module which 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: ipv4/enabled and ipv6/enabled: These leafs are used to enable or disable IPv4 and IPv6 on a specific interface. By enabling a protocol on an interface, an attacker might be able to create an unsecured path into a node (or through it if routing is also enabled). By disabling a protocol on an interface, an attacker might be able to force packets to be routed through some other interface or deny access to some or all of the network via that protocol. ipv4/address and ipv6/address: These lists specify the configured IP addresses on an interface. By modifying this information, an attacker can cause a node to either ignore messages destined to it or accept (at least at the IP layer) messages it would otherwise ignore. The use of filtering or security associations may reduce the potential damage in the latter case. ipv4/ip-forwarding and ipv6/ip-forwarding: These leafs allow a client to enable or disable the forwarding functions on the entity. By disabling the forwarding functions, an attacker would possibly be able to deny service to users. By enabling the forwarding functions, an attacker could open a conduit into an area. This might result in the area providing transit for packets it shouldn't or might allow the attacker access to the area bypassing security safeguards. ipv6/autoconf: The leafs in this branch control the autoconfiguration of IPv6 addresses and in particular whether temporary addresses are used or not. By modifying the corresponding leafs, an attacker might impact the addresses used by a node and thus indirectly the privacy of the users using the node. Bjorklund Expires March 9, 2013 [Page 15] Internet-Draft YANG IP Configuration September 2012 7. Acknowledgments The author wishes to thank Ladislav Lhotka, Juergen Schoenwaelder, and Dave Thaler for their helpful comments. Bjorklund Expires March 9, 2013 [Page 16] Internet-Draft YANG IP Configuration September 2012 8. References 8.1. Normative References [I-D.ietf-netmod-interfaces-cfg] Bjorklund, M., "A YANG Data Model for Interface Configuration", draft-ietf-netmod-interfaces-cfg-05 (work in progress), July 2012. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January 2004. [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, September 2007. [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless Address Autoconfiguration", RFC 4862, September 2007. [RFC4941] Narten, T., Draves, R., and S. Krishnan, "Privacy Extensions for Stateless Address Autoconfiguration in IPv6", RFC 4941, September 2007. [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, October 2010. [RFC6021] Schoenwaelder, J., "Common YANG Data Types", RFC 6021, October 2010. 8.2. Informative References [I-D.ietf-netmod-routing-cfg] Lhotka, L., "A YANG Data Model for Routing Configuration", draft-ietf-netmod-routing-cfg-04 (work in progress), July 2012. [RFC0826] Plummer, D., "Ethernet Address Resolution Protocol: Or converting network protocol addresses to 48.bit Ethernet address for transmission on Ethernet hardware", STD 37, RFC 826, November 1982. [RFC4293] Routhier, S., "Management Information Base for the Internet Protocol (IP)", RFC 4293, April 2006. Bjorklund Expires March 9, 2013 [Page 17] Internet-Draft YANG IP Configuration September 2012 [RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. Bierman, "Network Configuration Protocol (NETCONF)", RFC 6241, June 2011. [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, June 2011. Bjorklund Expires March 9, 2013 [Page 18] Internet-Draft YANG IP Configuration September 2012 Appendix A. Example: NETCONF reply This section gives an example of a reply to the NETCONF request for a device that implements the data model defined in this document. eth0 ethernetCsmacd 0 2
192.0.2.1 24
2001:DB8::1 32
0
Bjorklund Expires March 9, 2013 [Page 19] Internet-Draft YANG IP Configuration September 2012 Author's Address Martin Bjorklund Tail-f Systems Email: mbj@tail-f.com Bjorklund Expires March 9, 2013 [Page 20]