draft-ietf-shim6-multihome-shim-api-12.txt   draft-ietf-shim6-multihome-shim-api-13.txt 
SHIM6 Working Group M. Komu SHIM6 Working Group M. Komu
Internet-Draft HIIT Internet-Draft HIIT
Intended status: Informational M. Bagnulo Intended status: Informational M. Bagnulo
Expires: July 13, 2010 UC3M Expires: August 26, 2010 UC3M
K. Slavov K. Slavov
S. Sugimoto, Ed. S. Sugimoto, Ed.
Ericsson Ericsson
January 9, 2010 February 22, 2010
Socket Application Program Interface (API) for Multihoming Shim Socket Application Program Interface (API) for Multihoming Shim
draft-ietf-shim6-multihome-shim-api-12 draft-ietf-shim6-multihome-shim-api-13
Abstract
This document specifies sockets API extensions for the multihoming
shim layer. The API aims to enable interactions between applications
and the multihoming shim layer for advanced locator management, and
access to information about failure detection and path exploration.
This document is based on an assumption that a multihomed host is
equipped with a conceptual sub-layer (hereafter "shim") inside the IP
layer that maintains mappings between identifiers and locators.
Examples of the shim are SHIM6 and HIP.
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
skipping to change at page 1, line 36 skipping to change at page 1, line 48
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
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This Internet-Draft will expire on July 13, 2010. This Internet-Draft will expire on August 26, 2010.
Copyright Notice Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of Provisions Relating to IETF Documents
publication of this document (http://trustee.ietf.org/license-info). (http://trustee.ietf.org/license-info) in effect on the date of
Please review these documents carefully, as they describe your rights publication of this document. Please review these documents
and restrictions with respect to this document. carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
Abstract include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
This document specifies sockets API extensions for the multihoming described in the BSD License.
shim layer. The API aims to enable interactions between applications
and the multihoming shim layer for advanced locator management, and
access to information about failure detection and path exploration.
This document is based on an assumption that a multihomed host is
equipped with a conceptual sub-layer (hereafter "shim") inside the IP
layer that maintains mappings between identifiers and locators.
Examples of the shim are SHIM6 and HIP.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. System Overview . . . . . . . . . . . . . . . . . . . . . . . 6 3. System Overview . . . . . . . . . . . . . . . . . . . . . . . 6
4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 7 4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 7
5. Socket Options for Multihoming Shim Sub-layer . . . . . . . . 9 5. Socket Options for Multihoming Shim Sub-layer . . . . . . . . 9
5.1. SHIM_ASSOCIATED . . . . . . . . . . . . . . . . . . . . . 13 5.1. SHIM_ASSOCIATED . . . . . . . . . . . . . . . . . . . . . 12
5.2. SHIM_DONTSHIM . . . . . . . . . . . . . . . . . . . . . . 14 5.2. SHIM_DONTSHIM . . . . . . . . . . . . . . . . . . . . . . 13
5.3. SHIM_HOT_STANDBY . . . . . . . . . . . . . . . . . . . . 15 5.3. SHIM_HOT_STANDBY . . . . . . . . . . . . . . . . . . . . 14
5.4. SHIM_PATHEXPLORE . . . . . . . . . . . . . . . . . . . . 15 5.4. SHIM_LOC_LOCAL_PREF . . . . . . . . . . . . . . . . . . . 15
5.5. SHIM_LOC_LOCAL_PREF . . . . . . . . . . . . . . . . . . . 16 5.5. SHIM_LOC_PEER_PREF . . . . . . . . . . . . . . . . . . . 16
5.6. SHIM_LOC_PEER_PREF . . . . . . . . . . . . . . . . . . . 17 5.6. SHIM_LOC_LOCAL_RECV . . . . . . . . . . . . . . . . . . . 17
5.7. SHIM_LOC_LOCAL_RECV . . . . . . . . . . . . . . . . . . . 18 5.7. SHIM_LOC_PEER_RECV . . . . . . . . . . . . . . . . . . . 18
5.8. SHIM_LOC_PEER_RECV . . . . . . . . . . . . . . . . . . . 19 5.8. SHIM_LOC_LOCAL_SEND . . . . . . . . . . . . . . . . . . . 18
5.9. SHIM_LOC_LOCAL_SEND . . . . . . . . . . . . . . . . . . . 19 5.9. SHIM_LOC_PEER_SEND . . . . . . . . . . . . . . . . . . . 20
5.10. SHIM_LOC_PEER_SEND . . . . . . . . . . . . . . . . . . . 21 5.10. SHIM_LOCLIST_LOCAL . . . . . . . . . . . . . . . . . . . 20
5.11. SHIM_LOCLIST_LOCAL . . . . . . . . . . . . . . . . . . . 21 5.11. SHIM_LOCLIST_PEER . . . . . . . . . . . . . . . . . . . . 23
5.12. SHIM_LOCLIST_PEER . . . . . . . . . . . . . . . . . . . . 23 5.12. SHIM_APP_TIMEOUT . . . . . . . . . . . . . . . . . . . . 23
5.13. SHIM_APP_TIMEOUT . . . . . . . . . . . . . . . . . . . . 23 5.13. SHIM_PATHEXPLORE . . . . . . . . . . . . . . . . . . . . 24
5.14. SHIM_DEFERRED_CONTEXT_SETUP . . . . . . . . . . . . . . . 24 5.14. SHIM_DEFERRED_CONTEXT_SETUP . . . . . . . . . . . . . . . 25
5.15. Applicability . . . . . . . . . . . . . . . . . . . . . . 25 5.15. Applicability . . . . . . . . . . . . . . . . . . . . . . 26
5.16. Error Handling . . . . . . . . . . . . . . . . . . . . . 25 5.16. Error Handling . . . . . . . . . . . . . . . . . . . . . 26
6. Ancillary Data for Multihoming Shim Sub-layer . . . . . . . . 26 6. Ancillary Data for Multihoming Shim Sub-layer . . . . . . . . 26
6.1. Get Locator from Incoming Packet . . . . . . . . . . . . 27 6.1. Get Locator from Incoming Packet . . . . . . . . . . . . 27
6.2. Set Locator for Outgoing Packet . . . . . . . . . . . . . 27 6.2. Set Locator for Outgoing Packet . . . . . . . . . . . . . 28
6.3. Notification from Application to Multihoming Shim 6.3. Notification from Application to Multihoming Shim
Sub-layer . . . . . . . . . . . . . . . . . . . . . . . . 27 Sub-layer . . . . . . . . . . . . . . . . . . . . . . . . 28
6.4. Notification from Multihoming Shim Sub-layer to 6.4. Applicability . . . . . . . . . . . . . . . . . . . . . . 28
Application . . . . . . . . . . . . . . . . . . . . . . . 28
6.5. Applicability . . . . . . . . . . . . . . . . . . . . . . 28
7. Data Structures . . . . . . . . . . . . . . . . . . . . . . . 29 7. Data Structures . . . . . . . . . . . . . . . . . . . . . . . 29
7.1. Placeholder for Locator Information . . . . . . . . . . . 29 7.1. Placeholder for Locator Information . . . . . . . . . . . 29
7.1.1. Handling Locator behind NAT . . . . . . . . . . . . . 30 7.1.1. Handling Locator behind NAT . . . . . . . . . . . . . 30
7.2. Path Exploration Parameter . . . . . . . . . . . . . . . 31 7.2. Path Exploration Parameter . . . . . . . . . . . . . . . 31
7.3. Feedback Information . . . . . . . . . . . . . . . . . . 32 7.3. Feedback Information . . . . . . . . . . . . . . . . . . 32
8. System Requirements . . . . . . . . . . . . . . . . . . . . . 33 8. System Requirements . . . . . . . . . . . . . . . . . . . . . 33
9. Relation to Existing Sockets API Extensions . . . . . . . . . 33 9. Relation to Existing Sockets API Extensions . . . . . . . . . 33
10. Operational Considerations . . . . . . . . . . . . . . . . . . 34 10. Operational Considerations . . . . . . . . . . . . . . . . . . 33
10.1. Conflict Resolution . . . . . . . . . . . . . . . . . . . 34 10.1. Conflict Resolution . . . . . . . . . . . . . . . . . . . 34
10.2. Incompatiblility between IPv4 and IPv6 . . . . . . . . . 35 10.2. Incompatiblility between IPv4 and IPv6 . . . . . . . . . 34
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35
12. Protocol Constants and Variables . . . . . . . . . . . . . . . 35 12. Protocol Constants and Variables . . . . . . . . . . . . . . . 35
13. Security Considerations . . . . . . . . . . . . . . . . . . . 35 13. Security Considerations . . . . . . . . . . . . . . . . . . . 35
13.1. Treatment of Unknown Locator . . . . . . . . . . . . . . 35 13.1. Treatment of Unknown Locator . . . . . . . . . . . . . . 35
13.1.1. Treatment of Unknown Source Locator . . . . . . . . . 35 13.1.1. Treatment of Unknown Source Locator . . . . . . . . . 35
13.1.2. Treatment of Unknown Destination Locator . . . . . . . 36 13.1.2. Treatment of Unknown Destination Locator . . . . . . . 36
14. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 14. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
14.1. Changes from version 00 to version 01 . . . . . . . . . . 36 14.1. Changes from version 00 to version 01 . . . . . . . . . . 36
14.2. Changes from version 01 to version 02 . . . . . . . . . . 36 14.2. Changes from version 01 to version 02 . . . . . . . . . . 36
14.3. Changes from version 02 to version 03 . . . . . . . . . . 37 14.3. Changes from version 02 to version 03 . . . . . . . . . . 36
14.4. Changes from version 03 to version 04 . . . . . . . . . . 37 14.4. Changes from version 03 to version 04 . . . . . . . . . . 36
14.5. Changes from version 04 to version 05 . . . . . . . . . . 37 14.5. Changes from version 04 to version 05 . . . . . . . . . . 37
14.6. Changes from version 05 to version 06 . . . . . . . . . . 37 14.6. Changes from version 05 to version 06 . . . . . . . . . . 37
14.7. Changes from version 06 to version 07 . . . . . . . . . . 37 14.7. Changes from version 06 to version 07 . . . . . . . . . . 37
14.8. Changes from version 07 to version 08 . . . . . . . . . . 37 14.8. Changes from version 07 to version 08 . . . . . . . . . . 37
14.9. Changes from version 08 to version 09 . . . . . . . . . . 37 14.9. Changes from version 08 to version 09 . . . . . . . . . . 37
14.10. Changes from version 09 to version 10 . . . . . . . . . . 37 14.10. Changes from version 09 to version 10 . . . . . . . . . . 37
14.11. Changes from version 10 to version 11 . . . . . . . . . . 38 14.11. Changes from version 10 to version 11 . . . . . . . . . . 37
14.12. Changes from version 11 to version 12 . . . . . . . . . . 38 14.12. Changes from version 11 to version 12 . . . . . . . . . . 37
14.13. Changes from version 12 to version 13 . . . . . . . . . . 38
15. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 38 15. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 38
16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 38 16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 38
16.1. Normative References . . . . . . . . . . . . . . . . . . 38 16.1. Normative References . . . . . . . . . . . . . . . . . . 38
16.2. Informative References . . . . . . . . . . . . . . . . . 39 16.2. Informative References . . . . . . . . . . . . . . . . . 39
Appendix A. Context Forking . . . . . . . . . . . . . . . . . . . 39 Appendix A. Context Forking . . . . . . . . . . . . . . . . . . . 39
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 41 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 41
1. Introduction 1. Introduction
This document defines socket API extensions by which upper layer This document defines socket API extensions by which upper layer
skipping to change at page 4, line 34 skipping to change at page 4, line 34
Note that the shim sub-layer may conflict with other multihoming Note that the shim sub-layer may conflict with other multihoming
mechanisms such as SCTP and multipath mechanisms such as SCTP and multipath
TCP[I-D.ietf-shim6-applicability]. To avoid any conflict, only one TCP[I-D.ietf-shim6-applicability]. To avoid any conflict, only one
of SHIM6 and HIP should be in use. of SHIM6 and HIP should be in use.
In this document, syntax and semantics of the API are given in the In this document, syntax and semantics of the API are given in the
same way as the Posix standard [POSIX]. The API specifies how to use same way as the Posix standard [POSIX]. The API specifies how to use
ancillary data (aka cmsg) to access the locator information with ancillary data (aka cmsg) to access the locator information with
recvmsg() and/or sendmsg() I/O calls. The API is described in C recvmsg() and/or sendmsg() I/O calls. The API is described in C
language and data types are defined in the Posix format; intN_t means language and data types are defined in the Posix format; intN_t means
a singed integer of exactly N bits (e.g. int16_t) and uintN_t means a signed integer of exactly N bits (e.g. int16_t) and uintN_t means
an unsigned integer of exactly N bits (e.g. uint32_t). an unsigned integer of exactly N bits (e.g. uint32_t).
The distinction between "connected" sockets and "unconnected" sockets The distinction between "connected" sockets and "unconnected" sockets
is important when discussing the applicability of the socket API is important when discussing the applicability of the socket API
defined in this document. A connected socket is bound to a given defined in this document. A connected socket is bound to a given
peer, whereas an unconnected socket is not bound to any specific peer, whereas an unconnected socket is not bound to any specific
peers. A TCP socket becomes a connected socket when the TCP peers. A TCP socket becomes a connected socket when the TCP
connection establishment is completed. UDP sockets are unconnected, connection establishment is completed. UDP sockets are unconnected,
unless the application uses the connect() system call. unless the application uses the connect() system call.
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based manner. Applications and/or upper layer protocols may based manner. Applications and/or upper layer protocols may
provide positive feedbacks or negative feedbacks to the shim sub- provide positive feedbacks or negative feedbacks to the shim sub-
layer. Note that these feedbacks are mentioned in [RFC5534]: layer. Note that these feedbacks are mentioned in [RFC5534]:
* Applications and/or upper layer protocols (e.g., TCP) may * Applications and/or upper layer protocols (e.g., TCP) may
provide positive feedbacks to the shim sub-layer informing that provide positive feedbacks to the shim sub-layer informing that
the communication is going well. the communication is going well.
* Applications and/or upper layer protocols (e.g., TCP) may * Applications and/or upper layer protocols (e.g., TCP) may
provide negative feedbacks to the shim sub-layer informing that provide negative feedbacks to the shim sub-layer informing that
the communication status is not satisfactory. TCP may detect a the communication status is not satisfactory. TCP may detect a
problem when it does not receive any expected ACK message from problem when it does not receive any expected ACK message from
the peer. Besides, a receipt of an ICMP error message could be the peer. The REAP module may be triggered by these negative
a clue for the application to detect problems. The REAP module feedbacks and invoke the path exploration procedure.
may be triggered by these negative feedbacks and invoke the
path exploration procedure.
o Feedback from applications to the shim sub-layer. Applications o Feedback from applications to the shim sub-layer. Applications
should be able to inform the shim sub-layer of the timeout values should be able to inform the shim sub-layer of the timeout values
for detecting failures, sending keepalives, and starting the for detecting failures, sending keepalives, and starting the
exploration procedure. In particular, applications should be able exploration procedure. In particular, applications should be able
to suppress keepalives. to suppress keepalives.
o Hot-standby. Applications may request the shim sub-layer for the o Hot-standby. Applications may request the shim sub-layer for the
hot-standby capability. This means that, alternative paths are hot-standby capability. This means that, alternative paths are
known to be working in advance of a failure detection. In such a known to be working in advance of a failure detection. In such a
case, it is possible for the host to immediately replace the case, it is possible for the host to immediately replace the
current locator pair with an alternative locator pair. current locator pair with an alternative locator pair.
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should be able to obtain information about the locator pair which should be able to obtain information about the locator pair which
was actually used to send or receive the packet. was actually used to send or receive the packet.
* For inbound traffic, the application may be interested in the * For inbound traffic, the application may be interested in the
locator pair which was actually used to receive the packet. locator pair which was actually used to receive the packet.
* For outbound traffic, the application may be interested in the * For outbound traffic, the application may be interested in the
locator pair which was actually used to transmit the packet. locator pair which was actually used to transmit the packet.
In this way, applications may have additional control on the In this way, applications may have additional control on the
locator management. For example, an application becomes able to locator management. For example, an application becomes able to
verify if its preference for locator is actually applied to the verify if its preference for locator is actually applied to the
flow or not. flow or not.
o Applications should be able to specify if they want to defer the
context setup, or if they want context establishment to be started o Applications should be able to know if the shim-sublayer supports
immediately in the case where there is no available context. A deferred context setup or not.
deferred context setup means that the initiation of communication
should not be blocked to wait for completion of the context
establishment.
o An application should be able to know if the communication is now o An application should be able to know if the communication is now
being served by the shim sub-layer or not. being served by the shim sub-layer or not.
o An application should be able to use a common interface to access o An application should be able to use a common interface to access
an IPv4 locator and an IPv6 locator. an IPv4 locator and an IPv6 locator.
5. Socket Options for Multihoming Shim Sub-layer 5. Socket Options for Multihoming Shim Sub-layer
In this section, socket options that are specific to the shim sub- In this section, socket options that are specific to the shim sub-
layer are defined. layer are defined.
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fifth column shows the type of data structure specified along with fifth column shows the type of data structure specified along with
the socket option. By default, the data structure type is an the socket option. By default, the data structure type is an
integer. integer.
+-----------------------------+-----+-----+-----------------+-------+ +-----------------------------+-----+-----+-----------------+-------+
| optname | get | set | description | dtype | | optname | get | set | description | dtype |
+-----------------------------+-----+-----+-----------------+-------+ +-----------------------------+-----+-----+-----------------+-------+
| SHIM_ASSOCIATED | o | | Get the | int | | SHIM_ASSOCIATED | o | | Get the | int |
| | | | parameter which | | | | | | parameter which | |
| | | | indicates | | | | | | indicates | |
| | | | whether if the | | | | | | whether the | |
| | | | socket is | | | | | | socket is | |
| | | | associated with | | | | | | associated with | |
| | | | any shim | | | | | | any shim | |
| | | | context or not. | | | | | | context or not. | |
| SHIM_DONTSHIM | o | o | Get or set the | int | | SHIM_DONTSHIM | o | o | Get or set the | int |
| | | | parameter which | | | | | | parameter which | |
| | | | indicates | | | | | | indicates | |
| | | | whether to | | | | | | whether to | |
| | | | employ the | | | | | | employ the | |
| | | | multihoming | | | | | | multihoming | |
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| | | | packet. | | | | | | packet. | |
| SHIM_LOC_PEER_RECV | o | o | Get or set the | int | | SHIM_LOC_PEER_RECV | o | o | Get or set the | int |
| | | | parameter which | | | | | | parameter which | |
| | | | is used to | | | | | | is used to | |
| | | | request the | | | | | | request the | |
| | | | shim sub-layer | | | | | | shim sub-layer | |
| | | | to store the | | | | | | to store the | |
| | | | source locator | | | | | | source locator | |
| | | | of the received | | | | | | of the received | |
| | | | IP packet. | | | | | | IP packet. | |
| SHIM_LOC_LOCAL_SEND | o | o | Get or set the | *2 | | SHIM_LOC_LOCAL_SEND | o | o | Get or set the | *1 |
| | | | source locator | | | | | | source locator | |
| | | | of outgoing IP | | | | | | of outgoing IP | |
| | | | packets. | | | | | | packets. | |
| SHIM_LOC_PEER_SEND | o | o | Get or set the | *2 | | SHIM_LOC_PEER_SEND | o | o | Get or set the | *1 |
| | | | destination | | | | | | destination | |
| | | | locator of | | | | | | locator of | |
| | | | outgoing IP | | | | | | outgoing IP | |
| | | | packets. | | | | | | packets. | |
| SHIM_LOCLIST_LOCAL | o | o | Get or set the | *3 | | SHIM_LOCLIST_LOCAL | o | o | Get or set the | *2 |
| | | | list of | | | | | | list of | |
| | | | locators | | | | | | locators | |
| | | | associated with | | | | | | associated with | |
| | | | the local EID. | | | | | | the local EID. | |
| SHIM_LOCLIST_PEER | o | o | Get or set the | *3 | | SHIM_LOCLIST_PEER | o | o | Get or set the | *2 |
| | | | list of | | | | | | list of | |
| | | | locators | | | | | | locators | |
| | | | associated with | | | | | | associated with | |
| | | | the peer's EID. | | | | | | the peer's EID. | |
| SHIM_APP_TIMEOUT | o | o | Get or set the | int | | SHIM_APP_TIMEOUT | o | o | Get or set the | int |
| | | | timeout value | | | | | | timeout value | |
| | | | for detecting | | | | | | for detecting | |
| | | | failure. | | | | | | failure. | |
| SHIM_PATHEXPLORE | o | o | Get or set | *4 | | SHIM_PATHEXPLORE | o | o | Get or set | *3 |
| | | | parameters for | | | | | | parameters for | |
| | | | path | | | | | | path | |
| | | | exploration and | | | | | | exploration and | |
| | | | failure | | | | | | failure | |
| | | | detection. | | | | | | detection. | |
| SHIM_CONTEXT_DEFERRED_SETUP | o | o | Get or set the | int | | SHIM_CONTEXT_DEFERRED_SETUP | o | | Get the | int |
| | | | parameter which | | | | | | parameter which | |
| | | | indicates | | | | | | indicates | |
| | | | whether | | | | | | whether | |
| | | | deferred | | | | | | deferred | |
| | | | context setup | | | | | | context setup | |
| | | | is supported or | | | | | | is supported or | |
| | | | not. | | | | | | not. | |
+-----------------------------+-----+-----+-----------------+-------+ +-----------------------------+-----+-----+-----------------+-------+
Table 1: Socket options for multihoming shim sub-layer Table 1: Socket options for multihoming shim sub-layer
*1: Pointer to a shim_locator which is defined in Section 7. *1: Pointer to a shim_locator which is defined in Section 7.
*2: Pointer to shim_locator data structure. *2: Pointer to an array of shim_locator.
*3: Pointer to an array of shim_locator.
*4: Pointer to a shim_pathexplore which is defined in Section 7. *3: Pointer to a shim_pathexplore which is defined in Section 7.
Figure 2 illustrates how the shim specific socket options fit into Figure 2 illustrates how the shim specific socket options fit into
the system model of socket API. The figure shows that the shim sub- the system model of socket API. The figure shows that the shim sub-
layer and the additional protocol components (IPv4 and IPv6) below layer and the additional protocol components (IPv4 and IPv6) below
the shim sub-layer are new to the system model. As previously the shim sub-layer are new to the system model. As previously
mentioned, all the shim specific socket options are defined at the mentioned, all the shim specific socket options are defined at the
SOL_SHIM level. This design choice brings the following advantages: SOL_SHIM level. This design choice brings the following advantages:
1. The existing sockets API continue to work at the layer above the 1. The existing sockets API continue to work at the layer above the
shim sub-layer. That is, those legacy API handle IP addresses as shim sub-layer. That is, those legacy API handle IP addresses as
skipping to change at page 13, line 47 skipping to change at page 13, line 11
This option is meaningful when the locator information of the This option is meaningful when the locator information of the
received IP packet does not tell whether the identifier/locator received IP packet does not tell whether the identifier/locator
adaptation is performed or not. Note that the EID pair and the adaptation is performed or not. Note that the EID pair and the
locator pair may be identical in some cases. locator pair may be identical in some cases.
This option can be specified by getsockopt(). Thus, the option is This option can be specified by getsockopt(). Thus, the option is
read-only and the result (0/1/2) is set in the option value (the read-only and the result (0/1/2) is set in the option value (the
fourth argument of getsockopt()). fourth argument of getsockopt()).
When the application specifies the socket option to an unconnected
socket, an error code EOPNOTSUPP is returned to the application.
The data type of the option value is an integer. The option value The data type of the option value is an integer. The option value
indicates the presence of shim context. A return value 1 means that indicates the presence of shim context. A return value 1 means that
the socket is associated with a shim context at the shim sub-layer. the socket is associated with a shim context at the shim sub-layer.
A return value 0 indicates that there is no shim context associated A return value 0 indicates that there is no shim context associated
with the socket. A return value 2 means that it is not known whether with the socket. A return value 2 means that it is not known whether
the socket is associated with a shim context or not, and this must be the socket is associated with a shim context or not, and this must be
returned only when the socket is unconnected. In other words, the returned only when the socket is unconnected. In other words, the
returned value must be 0 or 1 when the socket is connected. returned value must be 0 or 1 when the socket is connected.
For example, the option can be used by the application as follows: For example, the option can be used by the application as follows:
skipping to change at page 15, line 22 skipping to change at page 14, line 37
The data type of the option value is an integer. The data type of the option value is an integer.
The option value can be set by setsockopt(). The option value can be set by setsockopt().
The option value can be read by getsockopt(). The option value can be read by getsockopt().
By default, the value is set to 0, meaning that hot-standby By default, the value is set to 0, meaning that hot-standby
connection is disabled. connection is disabled.
When the application specifies the socket option to an unconnected
socket, an error code EOPNOTSUPP is returned to the application.
When there is no shim context associated with the socket, an error
code ENOENT is returned to the application.
For example, an application can request establishment of a hot- For example, an application can request establishment of a hot-
standby connection by using the socket option as follows: standby connection by using the socket option as follows:
int optval; int optval;
optval = 1; optval = 1;
setsockopt(fd, SOL_SHIM, SHIM_HOT_STANDBY, &optval, setsockopt(fd, SOL_SHIM, SHIM_HOT_STANDBY, &optval,
sizeof(optval)); sizeof(optval));
For example, an application can get the option value by using the For example, an application can get the option value by using the
socket option as follows: socket option as follows:
int optval; int optval;
int len; int len;
len = sizeof(optval); len = sizeof(optval);
getsockopt(fd, SOL_SHIM, SHIM_HOT_STANDBY, &optval, &len); getsockopt(fd, SOL_SHIM, SHIM_HOT_STANDBY, &optval, &len);
5.4. SHIM_PATHEXPLORE 5.4. SHIM_LOC_LOCAL_PREF
The application may use this socket option to specify parameters
concerning path exploration. Path exploration is a procedure to find
an alternative locator pair to the current locator pair. As the REAP
specification defines, a peer may send Probe messages to find an
alternative locator pair.
The option is effective only when there is a shim context associated
with the socket.
The data type of the option value is a pointer to the buffer where a
set of information for path exploration is stored. The data
structure is defined in Section 7.
By default, the option value is set to NULL, meaning that the option
is disabled.
An error ENOENT is returned when there is no context associated with The SHIM_LOC_LOCAL_PREF option is used to get or set preference for a
source locator for outbound traffic within a given context. This
option is effective only when there is a shim context associated with
the socket. the socket.
For example, an application can set parameters for path exploration The preference of a locator is defined by a combination of priority
by using the socket option as follows. and weight as per DNS SRV[RFC2782]. Note that the SHIM6 base
protocol defines preference of locator in the same way.
struct shim6_pathexplore pe;
pe.pe_probenum = 4; /* times */
pe.pe_keepaliveto = 10; /* seconds */
pe.pe_initprobeto = 500; /* milliseconds */
pe.pe_reserved = 0;
setsockopt(fd, SOL_SHIM, SHIM_PATHEXPLORE, &pe, sizeof(pe));
For example, an application can get parameters for path exploration
by using the socket option as follows.
struct shim6_pathexplore pe;
int len;
len = sizeof(pe);
getsockopt(fd, SOL_SHIM, SHIM_PATHEXPLORE, &pe, &len);
5.5. SHIM_LOC_LOCAL_PREF
The SHIM_LOC_LOCAL_PREF option is used to get or set preferred
locator on local side within a given context. Hence this option is
effective only when there is a shim context associated with the
socket.
The data type of the option value is a pointer to a locator The data type of the option value is a pointer to a locator
information data structure which is defined in Section 7. information data structure which is defined in Section 7.
By default, the option value is set to NULL, meaning that the option By default, the option value is set to NULL, meaning that the option
is disabled. is disabled.
The preferred locator can be set by setsockopt(). The shim sub-layer The preferred locator can be set by setsockopt(). The shim sub-layer
shall verify requested locator before it updating the preferred shall verify requested locator before it updates the preferred
locator. locator.
An application can get the preferred locator by getsockopt(). An application can get the preferred locator by getsockopt().
An error ENOENT is returned when there is no context associated with When the application specifies the socket option to an unconnected
the socket. socket, an error code EOPNOTSUPP is returned to the application.
When there is no shim context associated with the socket, an error
code ENOENT is returned to the application.
An error EINVALIDLOCATOR is returned when the validation of the An error EINVALIDLOCATOR is returned when the validation of the
specified locator failed. specified locator fails.
For example, an application can set the preferred locator by using For example, an application can set the preferred locator by using
the socket option as follows. Note that some members of the the socket option as follows. Note that some members of the
shim_locator (lc_ifidx and lc_flags) are ignored in the set shim_locator (lc_ifidx and lc_flags) are ignored in the set
operation. operation.
struct shim_locator lc; struct shim_locator lc;
struct in6_addr ip6; struct in6_addr ip6;
/* ...set the locator (ip6)... */ /* ...set the locator (ip6)... */
memset(&lc, 0, sizeof(shim_locator)); memset(&lc, 0, sizeof(shim_locator));
lc.lc_family = AF_INET6; /* IPv6 */ lc.lc_family = AF_INET6; /* IPv6 */
lc.lc_ifidx = 0; lc.lc_ifidx = 0;
lc.lc_flags = 0; lc.lc_flags = 0;
lc.lc_preference = 255; lc.lc_prio = 1;
memcpy(lc.lc_addr, &ip6, sizeof(in6_addr)); lc.lc_weight = 10;
memcpy(&lc.lc_addr, &ip6, sizeof(in6_addr));
setsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_PREF, &lc, setsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_PREF, &lc,
sizeof(optval)); sizeof(optval));
For example, an application can get the preferred locator by using For example, an application can get the preferred locator by using
the socket option as follows. the socket option as follows.
struct shim_locator lc; struct shim_locator lc;
int len; int len;
len = sizeof(lc); len = sizeof(lc);
getsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_PREF, &lc, &len); getsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_PREF, &lc, &len);
5.6. SHIM_LOC_PEER_PREF 5.5. SHIM_LOC_PEER_PREF
The SHIM_LOC_PEER_PREF option is used to get or set preferred locator The SHIM_LOC_PEER_PREF option is used to get or set preference of a
on peer side within a given context. Hence this option is effective destination locator for outbound traffic within a given context.
only when there is a shim context associated with the socket. This option is effective only when there is a shim context associated
with the socket.
As defined earlier, the preference of a locator is defined by a
combination of priority and weight as per DNS SRV[RFC2782]. When
there are more than one candidate destination locators, the shim sub-
layer makes selection based on the priority and weight specified for
each locator.
The data type of the option value is a pointer to the locator The data type of the option value is a pointer to the locator
information data structure which is defined in Section 7. information data structure which is defined in Section 7.
By default, the option value is set to NULL, meaning that the option By default, the option value is set to NULL, meaning that the option
is disabled. is disabled.
The preferred locator can be set by setsockopt(). The shim sub-layer The preferred locator can be set by setsockopt(). The shim sub-layer
shall verify requested locator before it updating the preferred shall verify requested locator before it updating the preferred
locator. locator.
An application can get the preferred locator by getsockopt(). An application can get the preferred locator by getsockopt().
An error ENOENT is returned when there is no context associated with When the application specifies the socket option to an unconnected
the socket. socket, an error code EOPNOTSUPP is returned to the application.
When there is no shim context associated with the socket, an error
code ENOENT is returned to the application.
An error EINVALIDLOCATOR is returned when the validation of the An error EINVALIDLOCATOR is returned when the validation of the
requested locator fails. requested locator fails.
The usage of the option is same as that of SHIM_LOC_LOCAL_PREF. Note The usage of the option is same as that of SHIM_LOC_LOCAL_PREF. Note
that some members of the shim_locator (lc_ifidx and lc_flags) are that some members of the shim_locator (lc_ifidx and lc_flags) are
ignored in the set operation. ignored in the set operation.
5.7. SHIM_LOC_LOCAL_RECV 5.6. SHIM_LOC_LOCAL_RECV
The SHIM_LOC_LOCAL_RECV option can be used to request the shim sub- The SHIM_LOC_LOCAL_RECV option can be used to request the shim sub-
layer to store the destination locator of the received IP packet in layer to store the destination locator of the received IP packet in
an ancillary data object which can be accessed by recvmsg(). Hence an ancillary data object which can be accessed by recvmsg(). This
this option is effective only when there is a shim context associated option is effective only when there is a shim context associated with
with the socket. the socket.
The data type of the option value is integer. The option value The data type of the option value is integer. The option value
should be binary (0 or 1). By default, the option value is set to 0, should be binary (0 or 1). By default, the option value is set to 0,
meaning that the option is disabled. meaning that the option is disabled.
An application can set the option value by setsockopt(). An application can set the option value by setsockopt().
An application can get the option value by getsockopt(). An application can get the option value by getsockopt().
See Section 6 for the procedure to access locator information stored See Section 6 for the procedure to access locator information stored
in the ancillary data objects. in the ancillary data objects.
An error ENOENT is returned when there is no context associated with When the application specifies the socket option to an unconnected
the socket. socket, an error code EOPNOTSUPP is returned to the application.
When there is no shim context associated with the socket, an error
code ENOENT is returned to the application.
For example, an application can request the shim sub-layer to store For example, an application can request the shim sub-layer to store
destination locator by using the socket option as follows. destination locator by using the socket option as follows.
int optval; int optval;
optval = 1; optval = 1;
setsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_RECV, &optval, setsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_RECV, &optval,
sizeof(optval)); sizeof(optval));
For example, an application can get the option value as follows. For example, an application can get the option value as follows.
int optval; int optval;
int len; int len;
len = sizeof(optval); len = sizeof(optval);
getsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_RECV, &optval, &len); getsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_RECV, &optval, &len);
5.8. SHIM_LOC_PEER_RECV 5.7. SHIM_LOC_PEER_RECV
The SHIM_LOC_PEER_RECV option is used to request the shim sub-layer The SHIM_LOC_PEER_RECV option is used to request the shim sub-layer
to store the source locator of the received IP packet in an ancillary to store the source locator of the received IP packet in an ancillary
data object which can be accessed by recvmsg(). Hence this option is data object which can be accessed by recvmsg(). This option is
effective only when there is a shim context associated with the effective only when there is a shim context associated with the
socket. socket.
The data type of the option value is integer. The option value The data type of the option value is integer. The option value
should be binary (0 or 1). By default, the option value is set to 0, should be binary (0 or 1). By default, the option value is set to 0,
meaning that the option is disabled. meaning that the option is disabled.
The option value can be set by setsockopt(). The option value can be set by setsockopt().
The option value can be read by getsockopt(). The option value can be read by getsockopt().
See Section 6 for the procedure to access locator information stored See Section 6 for the procedure to access locator information stored
in the ancillary data objects. in the ancillary data objects.
An error ENOENT is returned when there is no context associated with When the application specifies the socket option to an unconnected
the socket. socket, an error code EOPNOTSUPP is returned to the application.
When there is no shim context associated with the socket, an error
code ENOENT is returned to the application.
The usage of the option is same as that of SHIM_LOC_LOCAL_RECV The usage of the option is same as that of SHIM_LOC_LOCAL_RECV
option. option.
5.9. SHIM_LOC_LOCAL_SEND 5.8. SHIM_LOC_LOCAL_SEND
The SHIM_LOC_LOCAL_SEND option is used to request the shim sub-layer The SHIM_LOC_LOCAL_SEND option is used to request the shim sub-layer
to use a specific locator as the source locator for the IP packets to to use a specific locator as the source locator for the IP packets to
be sent from the socket. Hence this option is effective only when be sent from the socket. This option is effective only when there is
there is a shim context associated with the socket. a shim context associated with the socket.
The data type of option value is pointer to shim_locator data The data type of option value is pointer to shim_locator data
structure. structure.
An application can set the local locator by setsockopt() providing a An application can set the local locator by setsockopt() providing a
valid locator which is stored in a shim_locator data structure. When valid locator which is stored in a shim_locator data structure. When
a zero-filled locator is specified, pre-existing setting of local a zero-filled locator is specified, pre-existing setting of local
locator is inactivated. locator is inactivated.
An application can get the local locator by getsockopt(). An application can get the local locator by getsockopt().
An error ENOENT is returned when there is no context associated with When the application specifies the socket option to an unconnected
the socket. socket, an error code EOPNOTSUPP is returned to the application.
An error EINVALIDLOCATOR is returned when invalid locator is When there is no shim context associated with the socket, an error
code ENOENT is returned to the application.
An error EINVALIDLOCATOR is returned when an invalid locator is
specified. specified.
For example, an application can request the shim sub-layer to use a For example, an application can request the shim sub-layer to use a
specific local locator by using the socket option as follows. specific local locator by using the socket option as follows.
struct shim_locator locator; struct shim_locator locator;
struct in6_addr ia6; struct in6_addr ia6;
/* an IPv6 address preferred for the source locator is copied /* an IPv6 address preferred for the source locator is copied
to the parameter ia6 */ to the parameter ia6 */
memset(&locator, 0, sizeof(locator)); memset(&locator, 0, sizeof(locator));
/* fill shim_locator data structure */ /* fill shim_locator data structure */
locator.lc_family = AF_INET6; locator.lc_family = AF_INET6;
locator.lc_ifidx = 1; locator.lc_ifidx = 1;
locator.lc_flags = 0; locator.lc_flags = 0;
locator.lc_preference = 0; locator.lc_prio = 0;
locator.lc_weight = 0;
memcpy(&locator.lc_addr, &ia6, sizeof(ia6)); memcpy(&locator.lc_addr, &ia6, sizeof(ia6));
setsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_SEND, &locator, setsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_SEND, &locator,
sizeof(locator)); sizeof(locator));
For example, an application can get the preferred local locator by For example, an application can get the preferred local locator by
using the socket option as follows. using the socket option as follows.
struct shim_locator locator; struct shim_locator locator;
memset(&locator, 0, sizeof(locator)); memset(&locator, 0, sizeof(locator));
getsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_SEND, &locator, getsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_SEND, &locator,
sizeof(locator)); sizeof(locator));
/* check locator */ /* check locator */
5.10. SHIM_LOC_PEER_SEND 5.9. SHIM_LOC_PEER_SEND
The SHIM_LOC_PEER_SEND option is used to request the shim sub-layer The SHIM_LOC_PEER_SEND option is used to request the shim sub-layer
to use a specific locator for the destination locator of IP packets to use a specific locator for the destination locator of IP packets
to be sent from the socket. Hence this option is effective only when to be sent from the socket. This option is effective only when there
there is a shim context associated with the socket. is a shim context associated with the socket.
The data type of the option value is a pointer to shim_locator data The data type of the option value is a pointer to shim_locator data
structure. structure.
An application can set the remote locator by setsockopt() providing a An application can set the remote locator by setsockopt() providing a
valid locator which is stored in a shim_locator data structure. When valid locator which is stored in a shim_locator data structure. When
a zero-filled locator is specified, pre-existing setting of remote a zero-filled locator is specified, pre-existing setting of remote
locator is inactivated. locator is inactivated.
An application can get the specified remote locator by getsockopt(). An application can get the specified remote locator by getsockopt().
An error ENOENT is returned when there is no context associated with When the application specifies the socket option to an unconnected
the socket. socket, an error code EOPNOTSUPP is returned to the application.
An error EINVALIDLOCATOR when invalid locator is specified. When there is no shim context associated with the socket, an error
code ENOENT is returned to the application.
The usage of the option is as the same as that of SHIM_LOC_LOCAL_SEND An error EINVALIDLOCATOR when invalid an locator is specified.
The usage of the option is the same as that of SHIM_LOC_LOCAL_SEND
option. option.
5.11. SHIM_LOCLIST_LOCAL 5.10. SHIM_LOCLIST_LOCAL
The SHIM_LOCLIST_LOCAL option is used to get or set the locator list The SHIM_LOCLIST_LOCAL option is used to get or set the locator list
associated with the local EID of the shim context associated with the associated with the local EID of the shim context associated with the
socket. Hence this option is effective only when there is a shim socket. This option is effective only when there is a shim context
context associated with the socket. associated with the socket.
The data type of the option value is a pointer to the buffer in which The data type of the option value is a pointer to the buffer in which
a locator list is stored. See Section 7 for the data structure for a locator list is stored. See Section 7 for the data structure for
storing the locator information. By default, the option value is set storing the locator information. By default, the option value is set
to NULL, meaning that the option is disabled. to NULL, meaning that the option is disabled.
An application can get the locator list by getsockopt(). Note that An application can get the locator list by getsockopt(). Note that
the size of the buffer pointed by optval argument should be large the size of the buffer pointed to by the optval argument should be
enough to store an array of locator information. The number of the large enough to store an array of locator information. The number of
locator information is not known beforehand. the locator information is not known beforehand.
The local locator list can be set by setsockopt(). The buffer The local locator list can be set by setsockopt(). The buffer
pointed by optval argument should contain an array of locator list. pointed to by the optval argument should contain an array of locator
structures.
An error ENOENT is returned when there is no context associated with When the application specifies the socket option to an unconnected
the socket. socket, an error code EOPNOTSUPP is returned to the application.
An error EINVALIDLOCATOR is returned when the validation of the When there is no shim context associated with the socket, an error
specified locator failed. code ENOENT is returned to the application.
An error EINVALIDLOCATOR is returned when the validation of any of
the specified locators failed.
An error ETOOMANYLOCATORS is returned when the number of locators An error ETOOMANYLOCATORS is returned when the number of locators
specified exceeds the limit (SHIM_MAX_LOCATORS). specified exceeds the limit (SHIM_MAX_LOCATORS), or when the size of
the buffer provided by the application is not large enough to store
the locator list provided by the shim sub-layer.
For example, an application can set a list of locators to be For example, an application can set a list of locators to be
associated with the local EID by using the socket option as follows: associated with the local EID by using the socket option as follows:
struct shim_locator locators[SHIM_MAX_LOCATORS]; struct shim_locator locators[SHIM_MAX_LOCATORS];
struct sockaddr_in *sin; struct sockaddr_in *sin;
struct sockaddr_in6 *sin6; struct sockaddr_in6 *sin6;
memset(locators, 0, sizeof(locators)); memset(locators, 0, sizeof(locators));
... ...
/* obtain local IP addresses from local interfaces */ /* obtain local IP addresses from local interfaces */
... ...
/* first locator (an IPv6 address) */ /* first locator (an IPv6 address) */
locators[0].lc_family = AF_INET6; locators[0].lc_family = AF_INET6;
locators[0].lc_ifidx = 0; locators[0].lc_ifidx = 0;
locators[0].lc_flags = 0; locators[0].lc_flags = 0;
locators[0].lc_preference = 1; locators[0].lc_prio = 1;
locators[0].lc_weight = 0;
memcpy(&locators[0].lc_addr, &sa6->sin6_addr, memcpy(&locators[0].lc_addr, &sa6->sin6_addr,
sizeof(sa6->sin6_addr)); sizeof(sa6->sin6_addr));
... ...
/* second locator (an IPv4 address) */ /* second locator (an IPv4 address) */
locators[1].lc_family = AF_INET; locators[1].lc_family = AF_INET;
locators[1].lc_ifidx = 0; locators[1].lc_ifidx = 0;
locators[1].lc_flags = 0; locators[1].lc_flags = 0;
locators[1].lc_preference = 0; locators[1].lc_prio = 0;
locators[1].lc_weight = 0;
memcpy(&locators[1].lc_addr, &sa->sin_addr, memcpy(&locators[1].lc_addr, &sa->sin_addr,
sizeof(sa->sin_addr)); sizeof(sa->sin_addr));
setsockopt(fd, SOL_SHIM, SHIM_LOCLIST_LOCAL, locators, setsockopt(fd, SOL_SHIM, SHIM_LOCLIST_LOCAL, locators,
sizeof(locators)); sizeof(locators));
For example, an application can get a list of locators that are For example, an application can get a list of locators that are
associated with the local EID by using the socket option as follows. associated with the local EID by using the socket option as follows.
struct shim_locator locators[SHIM_MAX_LOCATORS]; struct shim_locator locators[SHIM_MAX_LOCATORS];
memset(locators, 0, sizeof(locators)); memset(locators, 0, sizeof(locators));
getsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_RECV, locators, getsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_RECV, locators,
sizeof(locators)); sizeof(locators));
/* parse locators */ /* parse locators */
... ...
5.12. SHIM_LOCLIST_PEER 5.11. SHIM_LOCLIST_PEER
The SHIM_LOCLIST_PEER option is used to get or set the locator list The SHIM_LOCLIST_PEER option is used to get or set the locator list
associated with the peer EID of the shim context associated with the associated with the peer EID of the shim context associated with the
socket. Hence this option is effective only when there is a shim socket. This option is effective only when there is a shim context
context associated with the socket. associated with the socket.
The data type of the option value is a pointer to the buffer where a The data type of the option value is a pointer to the buffer where a
locator list is stored. See Section 7 for the data structure for locator list is stored. See Section 7 for the data structure for
storing the locator information. By default, the option value is set storing the locator information. By default, the option value is set
to NULL, meaning that the option is disabled. to NULL, meaning that the option is disabled.
An application can get the locator list by getsockopt(). Note that An application can get the locator list by getsockopt(). Note that
the size of the buffer pointed by optval argument should be large the size of the buffer pointed to by the optval argument should be
enough to store an array of locator information. The number of the large enough to store an array of locator information. The number of
locator information is not known beforehand. the locator information is not known beforehand.
An application can set the locator list by setsockopt(). The buffer An application can set the locator list by setsockopt(). The buffer
pointed by optval argument should contain an array of locator list. pointed to by the optval argument should contain an array of locator
list.
An error ENOENT is returned when there is no context associated with When the application specifies the socket option to an unconnected
the socket. socket, an error code EOPNOTSUPP is returned to the application.
An error EINVALIDLOCATOR is returned when the validation of the When there is no shim context associated with the socket, an error
specified locator failed. code ENOENT is returned to the application.
An error EINVALIDLOCATOR is returned when the validation of any of
the specified locators failed.
An error ETOOMANYLOCATORS is returned when the number of locators An error ETOOMANYLOCATORS is returned when the number of locators
specified exceeds the limit (SHIM_MAX_LOCATORS). specified exceeds the limit (SHIM_MAX_LOCATORS), or when the size of
the buffer provided by the application is not large enough to store
the locator list provided by the shim sub-layer.
The usage of the option is same as that of SHIM_LOCLIST_LOCAL. The usage of the option is same as that of SHIM_LOCLIST_LOCAL.
5.13. SHIM_APP_TIMEOUT 5.12. SHIM_APP_TIMEOUT
The SHIM_APP_TIMEOUT option is used to get or set the timeout value The SHIM_APP_TIMEOUT option is used to get or set the Send Timeout
for application to detect failure. Hence this option is effective value of the REAP protocol. This option is effective only when there
only when there is a shim context associated with the socket. is a shim context associated with the socket.
The data type of the option value is an integer. The value indicates The data type of the option value is an integer. The value indicates
the period of timeout in seconds to send a REAP Keepalive message the period of timeout in seconds to send a REAP Keepalive message
since the last outbound traffic. By default, the option value is set since the last outbound traffic. By default, the option value is set
to 0, meaning that the option is disabled. When the option is to 0, meaning that the option is disabled. When the option is
disabled, the REAP mechanism follows its default value of Send disabled, the REAP mechanism follows its default value of Send
Timeout value as specified in [RFC5534] Timeout value as specified in [RFC5534]
If the timeout value specified is longer than the Send Timeout When the application specifies the socket option to an unconnected
configured in the REAP component, the REAP Keepalive message should socket, an error code EOPNOTSUPP is returned to the application.
be suppressed.
An error ENOENT is returned when there is no context associated with When there is no shim context associated with the socket, an error
the socket. code ENOENT is returned to the application.
For example, an application can set the timeout value by using the For example, an application can set the timeout value by using the
socket option as follows. socket option as follows.
int optval; int optval;
optval = 15; /* 15 seconds */ optval = 15; /* 15 seconds */
setsockopt(fd, SOL_SHIM, SHIM_APP_TIMEOUT, &optval, setsockopt(fd, SOL_SHIM, SHIM_APP_TIMEOUT, &optval,
sizeof(optval)); sizeof(optval));
skipping to change at page 24, line 39 skipping to change at page 24, line 32
For example, an application can get the timeout value by using the For example, an application can get the timeout value by using the
socket option as follows. socket option as follows.
int optval; int optval;
int len; int len;
len = sizeof(optval); len = sizeof(optval);
getsockopt(fd, SOL_SHIM, SHIM_APP_TIMEOUT, &optval, &len); getsockopt(fd, SOL_SHIM, SHIM_APP_TIMEOUT, &optval, &len);
5.13. SHIM_PATHEXPLORE
The application may use this socket option to get or set parameters
concerning path exploration. Path exploration is a procedure to find
an alternative locator pair to the current locator pair. As the REAP
specification defines, a peer may send Probe messages to find an
alternative locator pair.
This option is effective only when there is a shim context associated
with the socket.
The data type of the option value is a pointer to the buffer where a
set of information for path exploration is stored. The data
structure is defined in Section 7.
By default, the option value is set to NULL, meaning that the option
is disabled.
When the application specifies the socket option to an unconnected
socket, an error code EOPNOTSUPP is returned to the application.
When there is no shim context associated with the socket, an error
code ENOENT is returned to the application.
For example, an application can set parameters for path exploration
by using the socket option as follows.
struct shim6_pathexplore pe;
pe.pe_probenum = 4; /* times */
pe.pe_keepaliveto = 10; /* seconds */
pe.pe_initprobeto = 500; /* milliseconds */
pe.pe_reserved = 0;
setsockopt(fd, SOL_SHIM, SHIM_PATHEXPLORE, &pe, sizeof(pe));
For example, an application can get parameters for path exploration
by using the socket option as follows.
struct shim6_pathexplore pe;
int len;
len = sizeof(pe);
getsockopt(fd, SOL_SHIM, SHIM_PATHEXPLORE, &pe, &len);
5.14. SHIM_DEFERRED_CONTEXT_SETUP 5.14. SHIM_DEFERRED_CONTEXT_SETUP
The SHIM_DEFERRED_CONTEXT_SETUP option is used to specify whether to The SHIM_DEFERRED_CONTEXT_SETUP option is used to check whether
enable deferred context setup or not. Deferred context setup means deferred context setup is possible or not. Deferred context setup
that the context is established in parallel with the data means that the context is established in parallel with the data
communication. Note that SHIM6 supports deferred context setup and communication. Note that SHIM6 supports deferred context setup and
HIP does not because EIDs in HIP (i.e., Host Identifiers) are non- HIP does not because EIDs in HIP (i.e., Host Identifiers) are non-
routable. routable.
The data type for the option value is an integer. The option value The data type for the option value is an integer. The option value
should be binary (0 or 1). By default, the value is set to 1, should be binary (0 or 1). The option value 1 means that the shim
meaning that the context setup is deferred. In order to disable the sub-layer supports deferred context setup.
option, the application should call setsockopt() with option value
set to 0.
Note that HIP does not support deferred context setup, by default.
When the application requests to enable deferred context setup in
case of HIP, it may mean that the application allows the system to
start TCP handshake even when there is no IPsec security association
with the peer. Such a usage of the SHIM_DEFERRED_CONTEXT_SETUP
option should be considered as experimental and left for further
study.
For example, an application can disable the deferred context setup by
using the socket option as follows:
int optval;
optval = 0;
setsockopt(fd, SOL_SHIM, SHIM_DEFERRED_CONTEXT_SETUP, When the application specifies the socket option to an unconnected
&optval, sizeof(optval)); socket, an error code EOPNOTSUPP is returned to the application.
For example, an application can get the option value as follows. For example, an application can check whether deferred context setup
is possible or not as follows:
int optval; int optval;
int len; int len;
len = sizeof(optval); len = sizeof(optval);
getsockopt(fd, SOL_SHIM, SHIM_DEFERRED_CONTEXT_SETUP, getsockopt(fd, SOL_SHIM, SHIM_DEFERRED_CONTEXT_SETUP,
&optval, &len); &optval, &len);
5.15. Applicability 5.15. Applicability
All the socket options for the shim sub-layer except for All the socket options defined in this section except for the
SHIM_HOT_STANDBY are applicable to both connected and unconnected SHIM_DONTSHIM option are applicable to applications that use
sockets. SHIM_HOT_STANDBY socket option is applicable only to connected sockets.
connected sockets. This is because the shim sub-layer cannot
initiate context establishment to create a hot standby connection All the socket options defined in this section except for the
when the peer's IP address is not known until the application writes SHIM_ASSOCIATED, SHIM_DONTSHIM and SHIM_CONTEXT_DEFERRED_SETUP
data to the unconnected socket. options are effective only when there is a shim context associated
with the socket.
5.16. Error Handling 5.16. Error Handling
If successful, getsockopt() and setsockopt() return 0; otherwise, the If successful, getsockopt() and setsockopt() return 0; otherwise, the
functions return -1 and set errno to indicate an error. functions return -1 and set errno to indicate an error.
The following are new error values defined for some shim specific The following are new error values defined for some shim specific
socket options indicating that the getsockopt() or setsockopt() socket options indicating that the getsockopt() or setsockopt()
finished incompletely: finished incompletely:
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padding if necessary padding if necessary
6.1. Get Locator from Incoming Packet 6.1. Get Locator from Incoming Packet
An application can get locator information from the received IP An application can get locator information from the received IP
packet by specifying the shim specific socket options for the socket. packet by specifying the shim specific socket options for the socket.
When SHIM_LOC_LOCAL_RECV and/or SHIM_LOC_PEER_RECV socket options are When SHIM_LOC_LOCAL_RECV and/or SHIM_LOC_PEER_RECV socket options are
set, the application can retrieve local and/or remote locator from set, the application can retrieve local and/or remote locator from
the ancillary data. the ancillary data.
When there is no shim context associated with the socket, the shim
sub-layer MUST return zero-filled locator information to the
application.
6.2. Set Locator for Outgoing Packet 6.2. Set Locator for Outgoing Packet
An application can specify the locators to be used for transmitting An application can specify the locators to be used for transmitting
an IP packet by sendmsg(). When the ancillary data of cmsg_type an IP packet by sendmsg(). When the ancillary data of cmsg_type
SHIM_LOC_LOCAL_SEND and/or SHIM_LOC_PEER_SEND are specified, the SHIM_LOC_LOCAL_SEND and/or SHIM_LOC_PEER_SEND are specified, the
application can explicitly specify the source and/or the destination application can explicitly specify the source and/or the destination
locators to be used for the communication over the socket. locators to be used for the communication over the socket. If the
specified locator pair is verified, the shim sub-layer overrides the
Note that the effect is limited to the datagram transmitted by the locator(s) of the outgoing IP packet. Note that the effect is
sendmsg(). limited to the datagram transmitted by the sendmsg().
If the specified locator pair is verified, the shim sub-layer When there is no shim context associated with the socket, an error
overrides the locators of the IP packet. code ENOENT is returned to the application.
An error EINVALIDLOCATOR is returned when validation of the specified An error code EINVALIDLOCATOR is returned when validation of the
locator failed. specified locator fails.
6.3. Notification from Application to Multihoming Shim Sub-layer 6.3. Notification from Application to Multihoming Shim Sub-layer
An application may provide feedbacks to the shim sub-layer about the An application may provide feedbacks to the shim sub-layer about the
communication status. Such feedbacks are particularly useful for the communication status. Such feedbacks are particularly useful for the
shim sub-layer in the absence of REAP mechanism to monitor the shim sub-layer in the absence of REAP mechanism to monitor the
reachability status of the currently used locator pair in a given reachability status of the currently used locator pair in a given
shim context. shim context.
The notification can be made by sendmsg() specifying a new ancillary The notification can be made by sendmsg() specifying a new ancillary
data called SHIM_FEEDBACK. The ancillary data can be handled by data called SHIM_FEEDBACK. The ancillary data can be handled by
specifying SHIM_FEEDBACK option in cmsg_type. specifying SHIM_FEEDBACK option in cmsg_type.
An error ENOENT is returned when there is no context associated with When there is no shim context associated with the socket, an error
the socket. code ENOENT is returned to the application.
See Section 7.3 for details of the data structure to be used. See Section 7.3 for details of the data structure to be used.
It is outside the scope of this document how the shim sub-layer would It is outside the scope of this document how the shim sub-layer would
react when a feedback is provided by an application. react when a feedback is provided by an application.
6.4. Notification from Multihoming Shim Sub-layer to Application 6.4. Applicability
The shim sub-layer MAY provide notification about a locator change
within a multihome shim context to applications that have concern
with the context. Such a notification may be useful, for example,
for an application which is sensitive to the characteristics of the
current path. A locator change is caused when either of local or
peer's locator (or both) is changed. Note that locators discussed
here are the ones that appear in the IP packet header, and not the
ones that are included in the locator list. A locator change may
take place asynchronously.
The notification is handled as an out-of-band data by the
application.
1. Application calls the select() system call by setting non-NULL
value for the fourth argument.
2. When there is a notification, the application reads out-of-band
data from the socket by calling recvmsg().
3. The application checks the flag in the msghdr (msg_flags) to see
if there is any notification about locator change delivered. If
the MSG_SHIM_LOCATOR_CHANGE flag is set, application parses the
chain of control message to read a pair of ancillary data objects
which contains the source locator and the destination locator.
Note that the direction of locator change is distinguished by the
value of cmsg_type; SHIM_LOC_*_RECV is used for inbound locator
change, and SHIM_LOC_*_SEND is used for outbound locator change.
There is no restriction in terms of applicability of the notification
about locator change. The notification can be delivered to any type
of socket (connected or unconnected, stream-oriented or datagram-
oriented).
6.5. Applicability
All the ancillary data for the shim sub-layer is applicable to both All the ancillary data for the shim sub-layer is applicable to
connected and unconnected sockets. connected sockets.
A care is needed when the SHIM_LOC_*_RECV socket option is used for Care is needed when the SHIM_LOC_*_RECV socket option is used for
stream-oriented sockets (e.g., TCP sockets) because there is no one- stream-oriented sockets (e.g., TCP sockets) because there is no one-
to-one mapping between a single send or receive operation and the to-one mapping between a single send or receive operation and the
data (e.g., a TCP segment) being received. In other words, there is data (e.g., a TCP segment) being received. In other words, there is
no gurantee that the locator(s) set in the SHIM_LOC_*_RECV ancillary no gurantee that the locator(s) set in the SHIM_LOC_*_RECV ancillary
data is identical to the locator(s) that appear in the IP packets data is identical to the locator(s) that appear in the IP packets
received. The shim sub-layer SHOULD provide the latest locator received. The shim sub-layer SHOULD provide the latest locator
information to the application in response to the SHIM_LOC_*_RECV information to the application in response to the SHIM_LOC_*_RECV
socket option. socket option.
7. Data Structures 7. Data Structures
This section data structures for the shim sub-layer. These data This section data structures for the shim sub-layer. These data
structures are either used as a parameter for setsockopt() or structures are either used as a parameter for setsockopt() or
getsockopt() (as mentioned in Section 5) or as a parameter for getsockopt() (as mentioned in Section 5) or as a parameter for
ancillary data to be processed by sendmsg() or recvmsg() (as ancillary data to be processed by sendmsg() or recvmsg() (as
mentioned in Section 6). mentioned in Section 6).
7.1. Placeholder for Locator Information 7.1. Placeholder for Locator Information
As defined in Section 5, the SHIM_LOC_LOCAL_PREF, SHIM_LOC_PEER_PREF, As defined in Section 5, the SHIM_LOC_*_PREF, SHIM_LOC_*_SEND, and
SHIM_LOCLIST_LOCAL, and SHIM_LOCLIST_PEER socket options need to SHIM_LOCLIST_* socket options need to handle one or more locator
handle one or more locator information. Locator information includes information. Locator information includes not only the locator
not only the locator itself but also additional information about the itself but also additional information about the locator which is
locator which is useful for locator management. A new data structure useful for locator management. A new data structure is defined to
is defined to serve as a placeholder for the locator information. serve as a placeholder for the locator information.
Figure 4 illustrates the data structure called shim_locator which Figure 4 illustrates the data structure called shim_locator which
stores a locator information. stores a locator information.
struct shim_locator { struct shim_locator {
uint8_t lc_family; /* address family */ uint8_t lc_family; /* address family */
uint8_t lc_proto; /* protocol */ uint8_t lc_proto; /* protocol */
uint16_t lc_port; /* port number */ uint16_t lc_port; /* port number */
uint16_t lc_flags; /* flags */ uint16_t lc_prio; /* preference value */
uint16_t lc_pref; /* preference value */ uint16_t lc_weight; /* weight */
uint32_t lc_ifidx; /* interface index */ uint32_t lc_ifidx; /* interface index */
struct in6_addr lc_addr; /* address */ struct in6_addr lc_addr; /* address */
uint16_t lc_flags; /* flags */
}; };
Figure 4: shim locator structure Figure 4: shim locator structure
lc_family lc_family
Address family of the locator (e.g. AF_INET, AF_INET6). It is Address family of the locator (e.g. AF_INET, AF_INET6). It is
required that the parameter contains non-zero value indicating the required that the parameter contains non-zero value indicating the
exact address family of the locator. exact address family of the locator.
lc_proto lc_proto
Internet Protocol number for the protocol which is used to handle Internet Protocol number for the protocol which is used to handle
locator behind NAT. Typically, this value is set as UDP (17) when locator behind NAT. Typically, this value is set as UDP (17) when
the locator is a UDP encapsulation interface. the locator is a UDP encapsulation interface.
lc_port lc_port
Port number which is used for handling locator behind NAT. Port number which is used for handling locator behind NAT.
lc_flags lc_prio
Each bit of the flags represents a specific characteristics of the The priority of the locator. The range is 0-65535. The lowest
locator. Hash Based Address (HBA) is defined as 0x01. priority value means the highest priority.
Cryptographically Generated Address (CGA) is defined as 0x02. lc_weight
lc_pref The weight value indicates a relative weight for locators with the
Preference of the locator. The preference is represented by an same priority value. The range is 0-65535.
integer.
lc_ifidx lc_ifidx
Interface index of the network interface to which the locator is Interface index of the network interface to which the locator is
assigned. This field should be valid only in a read assigned. This field should be valid only in a read
(getsockopt()) operation. (getsockopt()) operation.
lc_addr lc_addr
Contains the locator. In the case where a locator whose size is Contains the locator. In the case where a locator whose size is
smaller than 16 bytes, an encoding rule should be provided for smaller than 16 bytes, an encoding rule should be provided for
each locator of a given address family. For instance, in case of each locator of a given address family. For instance, in case of
AF_INET (IPv4), the locator should be in the format of an IPv4- AF_INET (IPv4), the locator should be in the format of an IPv4-
mapped IPv6 address as defined in [RFC4291]. mapped IPv6 address as defined in [RFC4291].
lc_flags
Each bit of the flags represents a specific characteristics of the
locator. Hash Based Address (HBA) is defined as 0x01.
Cryptographically Generated Address (CGA) is defined as 0x02.
7.1.1. Handling Locator behind NAT 7.1.1. Handling Locator behind NAT
Note that the locator information MAY contain a locator behind a Note that the locator information MAY contain a locator behind a
Network Address Translator (NAT). Such a situation may arise when Network Address Translator (NAT). Such a situation may arise when
the host is behind the NAT and uses a local address as a source the host is behind the NAT and uses a local address as a source
locator to communicate with the peer. Note that a NAT traversal locator to communicate with the peer. Note that a NAT traversal
mechanism for HIP is defined, which allows HIP host to tunnel control mechanism for HIP is defined, which allows HIP host to tunnel control
and data traffic over UDP[I-D.ietf-hip-nat-traversal]. Note also and data traffic over UDP[I-D.ietf-hip-nat-traversal]. Note also
that the locator behind NAT is not necessarily an IPv4 address but it that the locator behind NAT is not necessarily an IPv4 address but it
skipping to change at page 31, line 18 skipping to change at page 31, line 18
/* copy the private IPv4 address to the ia6 as an IPv4-mapped /* copy the private IPv4 address to the ia6 as an IPv4-mapped
IPv6 address */ IPv6 address */
memset(&locator, 0, sizeof(locator)); memset(&locator, 0, sizeof(locator));
/* fill shim_locator data structure */ /* fill shim_locator data structure */
locator.lc_family = AF_INET; locator.lc_family = AF_INET;
locator.lc_proto = IPPROTO_UDP; locator.lc_proto = IPPROTO_UDP;
locator.lc_port = 50500; locator.lc_port = 50500;
locator.lc_flags = 0; locator.lc_flags = 0;
locator.lc_pref = 0; locator.lc_prio = 0;
locator.lc_weight = 0;
locator.lc_ifidx = 3; locator.lc_ifidx = 3;
memcpy(&locator.lc_addr, &ia6, sizeof(ia6)); memcpy(&locator.lc_addr, &ia6, sizeof(ia6));
setsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_SEND, &locator, setsockopt(fd, SOL_SHIM, SHIM_LOC_LOCAL_SEND, &locator,
sizeof(locator)); sizeof(locator));
Figure 5: Handling locator behind NAT Figure 5: Handling locator behind NAT
7.2. Path Exploration Parameter 7.2. Path Exploration Parameter
skipping to change at page 33, line 12 skipping to change at page 33, line 12
unidirectional reachability between the locator pair in unidirectional reachability between the locator pair in
question. question.
* 3: Satisfactory. There is satisfactory unidirectional * 3: Satisfactory. There is satisfactory unidirectional
reachability between the locator pair in question. reachability between the locator pair in question.
reserved reserved
Reserved field. Must be ignored by the receiver. Reserved field. Must be ignored by the receiver.
8. System Requirements 8. System Requirements
This section gives system requirements posed by the sockets API As addressed in Section 5, most of the socket options and ancillary
defined in this document. There exist requirements for the system data defined in this document are applicable to connected sockets.
(kernel) to maintain the association between sockets and shim It is assumed that the kernel is capable of maintaining the
contexts. association between a connected socket and a shim context. This
requirement is considered to be reasonable because a pair of source
As addressed in Section 5, all the socket options and ancillary data and destination IP addresses is bound to a connected socket.
defined in this document except for the SHIM_HOT_STANDBY socket
option are applicable to both connected and unconnected sockets.
There are less system requirements to enable support for applications
that use connected sockets. This is because the kernel can maintain
the association between a connected socket and a shim context in a
static manner because a connected socket is bound to a source and
destination IP addresses (identifiers). The kernel should be able to
identify shim context associated with a connected socket by searching
shim context keyed by the pair of source and destination identifiers.
However, this is not the case for unnconnected sockets. The kernel
needs to dynamically resolve association between an unconnected
socket and a shim context, if any, upon packet processing. As to
outbound packet processing, the kernel needs to check if there is any
shim context whose EID pair matches with the source and destination
IP addresses of the user data originating from an unconnected socket.
If a matching context is found, the shim sub-layer performs packet
processing taking the application's preference into account. Note
that the shim sub-layer should be able to backtrack the socket from
which the user data was originated. As to inbound packet processing,
the shim sub-layer needs to check not only the IP header but also the
transport layer protocol header to resolve the destination socket.
If the destination socket is resolved and it contains any values
concerning the shim sub-layer socket options, the shim sub-layer
processes the IP packet as requested (e.g., set locator information
of received packet in the ancillary data).
9. Relation to Existing Sockets API Extensions 9. Relation to Existing Sockets API Extensions
This section explains relation between the sockets API defined in This section explains relation between the sockets API defined in
this document and the existing sockets API extensions. this document and the existing sockets API extensions.
As mentioned in Section 5, the basic assumption is that the existing As mentioned in Section 5, the basic assumption is that the existing
sockets API continues to work above the shim sub-layer. This means sockets API continues to work above the shim sub-layer. This means
that, the existing sockets API deals with identifiers, and the that, the existing sockets API deals with identifiers, and the
sockets API defined in this document deals with locators. sockets API defined in this document deals with locators.
SHIM_LOC_LOCAL_PREF and SHIM_LOC_PEER_PREF socket options are SHIM_LOC_LOCAL_SEND and SHIM_LOC_PEER_SEND socket options are
semantically similar to the IPV6_PKTINFO socket API in the sense that semantically similar to the IPV6_PKTINFO socket API in the sense that
both provide a means for application to set the source IP address of both provide a means for application to set the source IP address of
outbound IP packets. outbound IP packets.
SHIM_LOC_LOCAL_RECV and SHIM_LOC_PEER_RECV socket options are SHIM_LOC_LOCAL_RECV and SHIM_LOC_PEER_RECV socket options are
semantically similar to the IP_RECVDSTADDR and IPV6_PKTINFO socket semantically similar to the IP_RECVDSTADDR and IPV6_PKTINFO socket
APIs in the sense that both provides a means for application to get APIs in the sense that both provides a means for application to get
the source and/or destination IP address of inbound IP packets. the source and/or destination IP address of inbound IP packets.
getsockname() and getpeername() enable application to get 'name' of getsockname() and getpeername() enable application to get 'name' of
skipping to change at page 34, line 48 skipping to change at page 34, line 24
Socket options defined in Section 5 may cause conflicting situation Socket options defined in Section 5 may cause conflicting situation
when the target context is shared by multiple applications. In such when the target context is shared by multiple applications. In such
a case, the socket handler should inform the shim sub-layer that a case, the socket handler should inform the shim sub-layer that
context forking is required. In SHIM6, when a context is forked, an context forking is required. In SHIM6, when a context is forked, an
unique identifier called Forked Instance Identifier (FII) is assigned unique identifier called Forked Instance Identifier (FII) is assigned
to the newly forked context. The forked context is then exclusively to the newly forked context. The forked context is then exclusively
associated with the socket through which non-default preference value associated with the socket through which non-default preference value
was specified. The forked context is maintained by the shim sub- was specified. The forked context is maintained by the shim sub-
layer during the lifetime of associated socket instance. When the layer during the lifetime of associated socket instance. When the
socket is closed, the shim sub-layer SHOULD delete associated socket is closed, the shim sub-layer SHOULD delete associated
context. When a forked context is torn down, the SHIM6
implementation should notify the peer about the deletion of forked
context. context.
When the application specifies SHIM_LOC_*_SEND specifying a different
source or destination locator which does not have the highest
priority and weight specified by the SHIM_LOC_*_PREF, the shim sub-
layer SHOULD supersede the request made by SHIM_LOC_*_SEND over the
preference specified by SHIM_LOC_*_PREF.
When the peer provides preferences of the locators (e.g., a SHIM6
peer may send a locator with a Locator Preferences Option) which
conflict with preference specified by the applications either by
SHIM_LOC_PEER_SEND or SHIM_LOC_PEER_PREF, the shim sub-layer SHOULD
supersede the preference made by the application over the preference
specified by the peer.
10.2. Incompatiblility between IPv4 and IPv6 10.2. Incompatiblility between IPv4 and IPv6
The shim sub-layer performs identifier/locator adaptation. The shim sub-layer performs identifier/locator adaptation.
Therefore, in some cases, the whole IP header can be replaced with Therefore, in some cases, the whole IP header can be replaced with
new IP header of a different address family (e.g. conversion from new IP header of a different address family (e.g. conversion from
IPv4 to IPv6 or vice versa). Hence, there is an issue how to make IPv4 to IPv6 or vice versa). Hence, there is an issue how to make
the conversion with minimum impact. Note that this issue is common the conversion with minimum impact. Note that this issue is common
in other protocol conversion such as SIIT[RFC2765]. in other protocol conversion techniques
[RFC2765][I-D.ietf-behave-v6v4-xlate].
As addressed in the SIIT specification, some of the features (IPv6 As studied in the previous works on protocol
routing headers, hop-by-hop extension headers, or destination conversion[RFC2765][I-D.ietf-behave-v6v4-xlate], some of the features
(IPv6 routing headers, hop-by-hop extension headers, and destination
headers) from IPv6 are not convertible to IPv4. In addition, notion headers) from IPv6 are not convertible to IPv4. In addition, notion
of source routing is not exactly the same in IPv4 and IPv6. This of source routing is not exactly the same in IPv4 and IPv6. This
means that an error may occur during the conversion of identifier and means that an error may occur during the conversion of identifier and
locator. It is ffs exactly how the shim sub-layer should behave in locator. It is ffs exactly how the shim sub-layer should behave in
such erroneous cases. such erroneous cases.
11. IANA Considerations 11. IANA Considerations
This document contains no IANA consideration. This document contains no IANA consideration.
skipping to change at page 36, line 12 skipping to change at page 35, line 45
any of the local interface. If not, the shim sub-layer MUST reject any of the local interface. If not, the shim sub-layer MUST reject
the request and return an error message with the EINVALIDLOCATOR code the request and return an error message with the EINVALIDLOCATOR code
to the application. If the locator is confirmed to be available, the to the application. If the locator is confirmed to be available, the
shim sub-layer SHOULD initiate the procedure to update the locator shim sub-layer SHOULD initiate the procedure to update the locator
list. list.
Use of the following socket options and ancillary data may require Use of the following socket options and ancillary data may require
treatment of unknown source locator: treatment of unknown source locator:
o SHIM_LOC_LOCAL_SEND o SHIM_LOC_LOCAL_SEND
o SHIM_LOC_LOCAL_PREF o SHIM_LOC_LOCAL_PREF
o SHIM_LOC_LIST_LOCAL o SHIM_LOCLIST_LOCAL
13.1.2. Treatment of Unknown Destination Locator 13.1.2. Treatment of Unknown Destination Locator
If the shim sub-layer turns out to be SHIM6, the SHIM6 implementation If the shim sub-layer turns out to be SHIM6, the SHIM6 implementation
MUST reject the request for using unknown destination locator. MUST reject the request for using unknown destination locator.
If the shim sub-layer turns out to be HIP, the HIP implementation MAY If the shim sub-layer turns out to be HIP, the HIP implementation MAY
accept the request for using unknown destination locator. accept the request for using unknown destination locator.
Use of the following socket options and ancillary data may require Use of the following socket options and ancillary data may require
treatment of unknown destination locator: treatment of unknown destination locator:
o SHIM_LOC_PEER_SEND o SHIM_LOC_PEER_SEND
o SHIM_LOC_PEER_PREF o SHIM_LOC_PEER_PREF
o SHIM_LOC_LIST_PEER o SHIM_LOCLIST_PEER
14. Changes 14. Changes
14.1. Changes from version 00 to version 01 14.1. Changes from version 00 to version 01
o Define shim_locator{} data type which is a placeholder for o Define shim_locator{} data type which is a placeholder for
locator. locator.
o Define shim_pathexplore{} data type in which a set of REAP o Define shim_pathexplore{} data type in which a set of REAP
parameters are stored. parameters are stored.
o Remove descriptions about "stickiness" of socket options. o Remove descriptions about "stickiness" of socket options.
skipping to change at page 38, line 14 skipping to change at page 38, line 4
14.11. Changes from version 10 to version 11 14.11. Changes from version 10 to version 11
o Added short descriptions about connected sockets and unconnected o Added short descriptions about connected sockets and unconnected
sockets. sockets.
o Relaxed applicability of the socket options. o Relaxed applicability of the socket options.
o Relaxed applicability of the ancillary data. o Relaxed applicability of the ancillary data.
o Added notification about locator change. o Added notification about locator change.
14.12. Changes from version 11 to version 12 14.12. Changes from version 11 to version 12
o Reflected comments from Brian Karpenter.
o Reflected comments from Michael Scharf.
o Reflected comments from Brian Karpenter 14.13. Changes from version 12 to version 13
o Reflected comments from Michael Scharf
o Reflected comments from Sebastien Barre.
o Removed the description about the notification from the shim sub-
layer to applications.
o Narrowed down the scope of the applicability of the socket options
and the ancillary data.
15. Acknowledgments 15. Acknowledgments
Authors would like to thank Jari Arkko who participated in the Authors would like to thank Jari Arkko who participated in the
discussion that lead to the first version of this document, and discussion that lead to the first version of this document, and
Tatuya Jinmei who thoroughly reviewed the early version of this draft Tatuya Jinmei who thoroughly reviewed the early version of this draft
and provided detailed comments on sockets API related issues. Thomas and provided detailed comments on sockets API related issues. Thomas
Henderson provided valuable comments especially from HIP Henderson provided valuable comments especially from HIP
perspectives. perspectives.
Authors sincerely thank to the following people for their help to Authors sincerely thank to the following people for their helpful
improve this document: Samu Varjonen and Dmitriy Kuptsov. comments to the document: Samu Varjonen, Dmitriy Kuptsov, Brian
Carpenter, Michael Scharf, and Sebastien Barre
16. References 16. References
16.1. Normative References 16.1. Normative References
[POSIX] "IEEE Std. 1003.1-2001 Standard for Information Technology [POSIX] "IEEE Std. 1003.1-2001 Standard for Information Technology
-- Portable Operating System Interface (POSIX). Open group -- Portable Operating System Interface (POSIX). Open group
Technical Standard: Base Specifications, Issue 6, Technical Standard: Base Specifications, Issue 6,
http://www.opengroup.org/austin", December 2001. http://www.opengroup.org/austin", December 2001.
skipping to change at page 39, line 8 skipping to change at page 39, line 7
[RFC5533] Bagnulo, M. and E. Nordmark, "Level 3 multihoming shim [RFC5533] Bagnulo, M. and E. Nordmark, "Level 3 multihoming shim
protocol", RFC 5533, June 2009. protocol", RFC 5533, June 2009.
[RFC5534] Arkko, J. and I. Beijnum, "Failure Detection and Locator [RFC5534] Arkko, J. and I. Beijnum, "Failure Detection and Locator
Pair Exploration Protocol for IPv6 Multihoming", RFC 5534, Pair Exploration Protocol for IPv6 Multihoming", RFC 5534,
June 2009. June 2009.
16.2. Informative References 16.2. Informative References
[I-D.ietf-behave-v6v4-xlate]
Li, X., Bao, C., and F. Baker, "IP/ICMP Translation
Algorithm", draft-ietf-behave-v6v4-xlate-05 (work in
progress), December 2009.
[I-D.ietf-hip-nat-traversal] [I-D.ietf-hip-nat-traversal]
Komu, M., Henderson, T., Tschofenig, H., Melen, J., and A. Komu, M., Henderson, T., Tschofenig, H., Melen, J., and A.
Keranen, "Basic HIP Extensions for Traversal of Network Keranen, "Basic HIP Extensions for Traversal of Network
Address Translators", Internet Address Translators", Internet
Draft draft-ietf-hip-nat-traversal-09, October 2009. Draft draft-ietf-hip-nat-traversal-09, October 2009.
[I-D.ietf-shim6-app-refer] [I-D.ietf-shim6-app-refer]
Nordmark, E., "Shim6 Application Referral Issues", Nordmark, E., "Shim6 Application Referral Issues",
draft-ietf-shim6-app-refer-00 (work in progress), draft-ietf-shim6-app-refer-00 (work in progress),
July 2005. July 2005.
[I-D.ietf-shim6-applicability] [I-D.ietf-shim6-applicability]
Abley, J., Bagnulo, M., and A. Garcia-Martinez, Abley, J., Bagnulo, M., and A. Garcia-Martinez,
"Applicability Statement for the Level 3 Multihoming Shim "Applicability Statement for the Level 3 Multihoming Shim
Protocol (Shim6)", draft-ietf-shim6-applicability-04 (work Protocol (Shim6)", draft-ietf-shim6-applicability-04 (work
in progress), November 2009. in progress), November 2009.
[RFC2765] Nordmark, E., "Stateless IP/ICMP Translation Algorithm [RFC2765] Nordmark, E., "Stateless IP/ICMP Translation Algorithm
(SIIT)", RFC 2765, February 2000. (SIIT)", RFC 2765, February 2000.
[RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)", RFC 2782,
February 2000.
[RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)",
RFC 3972, March 2005. RFC 3972, March 2005.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006. Architecture", RFC 4291, February 2006.
[RFC5535] Bagnulo, M., "Hash Based Addresses (HBA)", RFC 5535, [RFC5535] Bagnulo, M., "Hash Based Addresses (HBA)", RFC 5535,
June 2009. June 2009.
Appendix A. Context Forking Appendix A. Context Forking
 End of changes. 106 change blocks. 
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