RFC 2855

DHCP for IEEE 1394

📅 published June 2000, from ietf

DHCP for IEEE 1394 💖

RFC 2855 🎀

  • Author: Kenji Fujisawa, Sony Corporation 💅
  • Category: Standards Track ✨
  • Date: June 2000 🌸
  • Obsoletes / Updates: the original title block doesn't list anything it obsoletes or updates 🦋

Status of this Memo 📜

okay so this doc is an Internet standards track protocol for the Internet community 💜 It's also asking for discussion and suggestions for improvements 🫶 For the current standardization state and status, check the "Internet Official Protocol Standards" (STD 1) 👑 And the memo can be distributed with no limits, bestie 🌈

Copyright (C) The Internet Society (2000). All Rights Reserved. 🔒

Abstract ✨

so IEEE Std 1394-1995 is the standard for a High Performance Serial Bus 🔥 Because 1394 uses a different link-layer addressing method than conventional IEEE802/Ethernet, the usage of some fields must be clarified to achieve interoperability 🙈 This memo explains the 1394 specific usage of some fields in DHCP messages 💅

1. Introduction 🦋

Okay, the IEEE Std 1394-1995 is the standard for a High Performance Serial Bus, again 💖 The IETF IP1394 Working Group figured out how to carry IPv4 datagrams and 1394 ARP packets over an IEEE1394 network [RFC2734] 🧚

The Dynamic Host Configuration Protocol (DHCP) [RFC2131] is the framework that passes configuration info to hosts on a TCP/IP network 🌸

Since 1394 uses a different link-layer addressing method than conventional IEEE802/Ethernet, some fields must be clarified for interop 🫶 This memo covers the 1394 specific usage of some DHCP fields. For the DHCP mechanism and the explanation of each field, see [RFC2131] 📖

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] 💜 these are the iconic words that set the requirement levels, so pay attention 👑

With conventional link-layer protocols like Ethernet, the 'chaddr' (client hardware address) field can be used to return a reply message from a DHCP server (or relay-agent) to a client 🍓 But a 1394 link address (node_ID) is transient and won't stay consistent across the 1394 bridge, so we chose NOT to put it in the 'chaddr' field 🙈 A DHCP client should ask the server to send a broadcast reply by setting the BROADCAST flag when 1394 ARP isn't possible yet ✨

Note: In general, the use of a broadcast reply is discouraged, but we consider the impact in a 1394 network as a non issue. 💅

3. 1394 specific usage of DHCP message fields 🎀

Following these rules should be used when a DHCP client is connected to an IEEE1394 network 🦋

'htype' (hardware address type) MUST be 24 [ARPPARAM]. 💖

'hlen' (hardware address length) MUST be 0. 🌸

The 'chaddr' (client hardware address) field is reserved 😭 The sender MUST set this field to zero, and the recipient and the relay agent MUST ignore its value on receipt. 🫶

A DHCP client on 1394 SHOULD set a BROADCAST flag in DHCPDISCOVER and DHCPREQUEST messages (and set 'ciaddr' to zero) so the server (or the relay agent) broadcasts its reply to the client 📣

Note: As described in [RFC2131], 'ciaddr' MUST be filled in with the client's IP address during BOUND, RENEWING or REBINDING state, therefore, the BROADCAST flag MUST NOT be set. In these cases, the DHCP server unicasts DHCPACK message to the address in 'ciaddr'. The link address will be resolved by 1394 ARP. 🧚

The 'client identifier' option MUST be used in DHCP messages from the client to the server, since 'chaddr' isn't available 🔥 The 'client identifier' option may consist of any data 💅 Because every IP over 1394 node has an EUI-64 (node unique ID), the EUI-64 makes an obvious 'client identifier' 👑 1394 clients SHOULD include an EUI-64 identifier in the 'client identifier' option. The type value for the EUI-64 is 27 [ARPPARAM], and the format looks like this:

 Code  Len   Type  Client-Identifier
+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
|  61 |  9  | 27  |           EUI-64 (node unique ID)             |
+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+

Note that using other 'client identifier' types, like a fully qualified domain name (FQDN), is not precluded by this memo 🌈

For more details, see "9.14. Client-identifier" in [RFC2132] 📖

4. Security Considerations 🚨

DHCP currently provides no authentication or security mechanisms 💀 Potential exposures to attack are discussed in section 7 of the DHCP protocol specification [RFC2131] 🙈

A malicious client can falsify its EUI-64 identifier, thus masquerading as another client. 💀😭 This is an absolute villain arc, so keep an eye out for it.

Acknowledgments 🫶

The author appreciates the members of the Dynamic Host Configuration Working Group for their review and valuable comments 💖

References 📚

[RFC2734]  Johansson, P., "IPv4 over IEEE 1394", RFC 2734, December
           1999.

[RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
           Requirement Levels", RFC 2119, March 1997.

[RFC2131]  Droms, R., "Dynamic Host Configuration Protocol", RFC
           2131, March 1997.

[RFC2132]  Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
           Extensions", RFC 2132, March 1997.

[ARPPARAM] http://www.iana.org/numbers.html

Author's Address 🏠

Kenji Fujisawa
Sony Corporation
6-7-35, Kitashinagawa,
Shinagawa-ku, Tokyo, 141-0001 Japan

Phone: +81-3-5448-8507
EMail: fujisawa@sm.sony.co.jp

Copyright (C) The Internet Society (2000). All Rights Reserved.

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Acknowledgement 🌸

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