IPv6 Socket API for Source Address Selection
RFC 5014
| Document | Type |
RFC - Informational
(September 2007; No errata)
Was draft-chakrabarti-ipv6-addrselect-api (individual in int area)
|
|
|---|---|---|---|
| Last updated | 2015-10-14 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 5014 (Informational) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Jari Arkko | ||
| Send notices to | ipv6-chairs@ietf.org | ||
Network Working Group E. Nordmark
Request for Comments: 5014 Sun Microsystems, Inc.
Category: Informational S. Chakrabarti
Azaire Networks
J. Laganier
DoCoMo Euro-Labs
September 2007
IPv6 Socket API for Source Address Selection
Status of This Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Abstract
The IPv6 default address selection document (RFC 3484) describes the
rules for selecting source and destination IPv6 addresses, and
indicates that applications should be able to reverse the sense of
some of the address selection rules through some unspecified API.
However, no such socket API exists in the basic (RFC 3493) or
advanced (RFC 3542) IPv6 socket API documents. This document fills
that gap partially by specifying new socket-level options for source
address selection and flags for the getaddrinfo() API to specify
address selection based on the source address preference in
accordance with the socket-level options that modify the default
source address selection algorithm. The socket API described in this
document will be particularly useful for IPv6 applications that want
to choose between temporary and public addresses, and for Mobile IPv6
aware applications that want to use the care-of address for
communication. It also specifies socket options and flags for
selecting Cryptographically Generated Address (CGA) or non-CGA source
addresses.
Nordmark, et al. Informational [Page 1]
RFC 5014 Socket API for Source Address Selection September 2007
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Definition Of Terms . . . . . . . . . . . . . . . . . . . . . 5
3. Usage Scenario . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Design Alternatives . . . . . . . . . . . . . . . . . . . . . 6
5. Address Preference Flags . . . . . . . . . . . . . . . . . . . 7
6. Additions to the Socket Interface . . . . . . . . . . . . . . 9
7. Additions to the Protocol-Independent Nodename Translation . . 10
8. Application Requirements . . . . . . . . . . . . . . . . . . . 11
9. Usage Example . . . . . . . . . . . . . . . . . . . . . . . . 13
10. Implementation Notes . . . . . . . . . . . . . . . . . . . . . 13
11. Mapping to Default Address Selection Rules . . . . . . . . . . 14
12. IPv4-Mapped IPv6 Addresses . . . . . . . . . . . . . . . . . . 16
13. Validating Source Address Preferences . . . . . . . . . . . . 16
14. Summary of New Definitions . . . . . . . . . . . . . . . . . . 19
15. Security Considerations . . . . . . . . . . . . . . . . . . . 19
16. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19
17. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20
17.1. Normative References . . . . . . . . . . . . . . . . . . 20
17.2. Informative References . . . . . . . . . . . . . . . . . 20
Appendix A. Per-Packet Address Selection Preference . . . . . . . 21
Appendix B. Intellectual Property Statement . . . . . . . . . . . 22
1. Introduction
[RFC3484] specifies the default address selection rules for IPv6
[RFC2460]. This document defines socket API extensions that allow
applications to override the default choice of source address
selection. It therefore indirectly affects the destination address
selection through getaddrinfo(). Privacy considerations [RFC3041]
have introduced "public" and "temporary" addresses. IPv6 Mobility
[RFC3775] introduces "home address" and "care-of address" definitions
in the mobile systems.
The default address selection rules in [RFC3484], in summary, are
that a public address is preferred over a temporary address, that a
mobile IPv6 home address is preferred over a care-of address, and
that a larger scope address is preferred over a smaller scope
address. Although it is desirable to have default rules for address
selection, an application may want to reverse certain address
selection rules for efficiency and other application-specific
reasons.
Currently, IPv6 socket API extensions provide mechanisms to choose a
specific source address through simple bind() operation or
IPV6_PKTINFO socket option [RFC3542]. However, in order to use
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