Internet DRAFT - draft-qin-6man-nb-option
draft-qin-6man-nb-option
Network Working Group C. Qin, Ed.
Internet-Draft Y. Xi
Intended status: Standards Track W. Xu
Expires: August 24, 2019 Alibaba-Inc
February 20, 2019
IPv6 Router Advertisement Option for Network Boot
draft-qin-6man-nb-option-03
Abstract
This document specifies an IPv6 Router Advertisement (RA) option
(called "Boot File URL option") to allow IPv6 routers to advertise
configuration information for booting a node from the network.
Status of This Memo
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This Internet-Draft will expire on August 24, 2019.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2
2. Option . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Boot File Uniform Resource Locator (URL) Option . . . . . 3
3. Implementation Considerations . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
This document describes an IPv6 Neighbor Discovery (ND) option
(called BFURL option) that can be used to provide configuration
information for nodes to be booted from network instead of local
media.
IPv6 Stateless Address Autoconfiguration (SLAAC) [RFC4862] and IPv6
Neighbor Discovery (ND) [RFC4861] define ways to configure IPv6
addresses, on-link prefix list, default routers and other parameters.
The existing ND message (RA) is used to carry this network boot
information. Nodes can get the boot file url and parameters through
RA messages via BFRUL option. A boot file can be a boot-loader
program or a minimal OS kernel. The node firmware needs to download
the boot file and execute it.
This approach is useful in networks with no DHCPv6 infrastructure.
The intention is to simplify the implementation of first-stage
communicating functionalities of the nodes (i.e. PXE firmware), and
network. The distribution of additional information and subsequent
communications between the node and network side (e.g., an install
server) should be handled by applications built in the boot file.
The configuration of a Boot-File-URL would be required onto routers
sending RA messages. The configuration mechanism (manual or
automatic) is out of scope of this document.
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 RFC 2119 [RFC2119].
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2. Option
The option formats comply with ND options per [RFC4861].
2.1. Boot File Uniform Resource Locator (URL) Option
Routers send this option to nodes with a URL to a boot file.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | P-Len | Reserved1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Boot-File-URL (variable length) ~
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | |
+-+-+-+-+-+-+-+-+ Padding-Data (optional, 0-7 octets) +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1
Fields description:
Type TBD.
Length 8-bit unsigned integer. The length of this
option (including the Type and Length fields)
in units of 8 octets.
P-Len 4-bit unsigned integer. The length of
Padding-Data field in units of octets.
Reserved1 This field is unused. It MUST be initialized
to zero and MUST be ignored by the receiver.
Reserved2 This field is unused. It MUST be initialized
to zero and MUST be ignored by the receiver.
Boot-File-URL The URL for a boot file in string. Its
format MUST comply with [RFC3986].
Padding-Data 0-7 octets of zeros for padding the encoding
of Boot-File-URL if required. Since the
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length of option MUST be a multiple of 8
octets, for the minimum multiple, the
remaining octets following the encoding part
of Boot-File-URL MUST be padded with zeros.
3. Implementation Considerations
In the current format of BFURL option (Section 2.1), there is no
field defined to identify the architectures of nodes to be booted
from network. Implementers should be aware of the details of their
deployment environment and tailor the boot file to accommodate the
network booting nodes of different types.
A new IPv6 Router Solicitation (RS) option can be defined in the
future for nodes to send the information of architecture types they
support to the network side for the selection of appropriate boot
file.
Also, there is no field defined in the BFURL option nor any
individual option specified in this document for the network booting
parameters. We recommend that, the basic parameters required should
be embedded in the boot file itself. That can ease the configuration
of network booting functionality on the network devices. After the
boot file or the built-in application is successfully executed, they
should take the responsibility of guiding the subsequent phases of
installation.
This document puts no constraints on the protocols used to download
the boot file. While it is possible that the downloading protocol is
specified in the URL by syntax.
Domain names may be used in the boot file URL rather than an IPv6
address. That requires the network booting nodes to support DNS
implementation. The DNS server information can be also distributed
by RA options per [RFC8106].
4. IANA Considerations
This document requires a new ND option type to be allocated.
Option Name Type
Boot-File-URL TBD.
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5. Security Considerations
Rogue RA messages with wrong URL information may be received in the
untrusted environment and direct the network booting nodes to
download boot file from an attacker's file server. The Secure
Neighbor Discovery (SEND) protocol [RFC3971] is designed to allow all
ND options including the BFURL option specified in this document to
be sent with digital signature, which prevent this kind of attack.
To protect the boot file downloading process, using protocols like
HTTPS is recommended. Further, security mechanisms can be
implemented within the built-in application or the boot file to be
executed, to secure the communications in the later stage.
6. Acknowledgements
The authors would like to thank Jinhui, He Qiang for their comments
and inputs.
7. References
7.1. 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,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander,
"SEcure Neighbor Discovery (SEND)", RFC 3971,
DOI 10.17487/RFC3971, March 2005,
<https://www.rfc-editor.org/info/rfc3971>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/info/rfc4861>.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862,
DOI 10.17487/RFC4862, September 2007,
<https://www.rfc-editor.org/info/rfc4862>.
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[RFC8106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
"IPv6 Router Advertisement Options for DNS Configuration",
RFC 8106, DOI 10.17487/RFC8106, March 2017,
<https://www.rfc-editor.org/info/rfc8106>.
[UEFI23] UEFI Forum, "Unified Extensible Firmware Interface (UEFI)
Specification, Version 2.7 Errata A", August 2017,
<http://www.uefi.org/>.
7.2. Informative References
[RFC3315] Droms, R., Ed., Bound, J., Volz, B., Lemon, T., Perkins,
C., and M. Carney, "Dynamic Host Configuration Protocol
for IPv6 (DHCPv6)", RFC 3315, DOI 10.17487/RFC3315, July
2003, <https://www.rfc-editor.org/info/rfc3315>.
[RFC4578] Johnston, M. and S. Venaas, Ed., "Dynamic Host
Configuration Protocol (DHCP) Options for the Intel
Preboot eXecution Environment (PXE)", RFC 4578,
DOI 10.17487/RFC4578, November 2006,
<https://www.rfc-editor.org/info/rfc4578>.
[RFC5970] Huth, T., Freimann, J., Zimmer, V., and D. Thaler, "DHCPv6
Options for Network Boot", RFC 5970, DOI 10.17487/RFC5970,
September 2010, <https://www.rfc-editor.org/info/rfc5970>.
Authors' Addresses
Chao Qin (editor)
Alibaba-Inc
P.R.China
Email: jacni@jacni.com
Yongqing Xi
Alibaba-Inc
P.R.China
Email: yongqing.xyq@alibaba-inc.com
Wei Xu
Alibaba-Inc
P.R.China
Email: arthur.xw@alibaba-inc.com
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