Constrained Join Proxy for Bootstrapping Protocols
draft-ietf-anima-constrained-join-proxy-03
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| Authors | Michael Richardson , Peter Van der Stok , Panos Kampanakis | ||
| Last updated | 2021-08-09 | ||
| Replaces | draft-vanderstok-anima-constrained-join-proxy | ||
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draft-ietf-anima-constrained-join-proxy-03
anima Working Group M. Richardson
Internet-Draft Sandelman Software Works
Intended status: Standards Track P. van der Stok
Expires: February 10, 2022 vanderstok consultancy
P. Kampanakis
Cisco Systems
August 09, 2021
Constrained Join Proxy for Bootstrapping Protocols
draft-ietf-anima-constrained-join-proxy-03
Abstract
This document defines a protocol to securely assign a Pledge to a
domain, represented by a Registrar, using an intermediary node
between Pledge and Registrar. This intermediary node is known as a
"constrained Join Proxy".
This document extends the work of [RFC8995] by replacing the Circuit-
proxy between Pledge and Registrar by a stateless/stateful
constrained (CoAP) Join Proxy. It relays join traffic from the
Pledge to the Registrar.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 10, 2022.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
4. Join Proxy functionality . . . . . . . . . . . . . . . . . . 4
5. Join Proxy specification . . . . . . . . . . . . . . . . . . 5
5.1. Statefull Join Proxy . . . . . . . . . . . . . . . . . . 5
5.2. Stateless Join Proxy . . . . . . . . . . . . . . . . . . 7
5.3. Stateless Message structure . . . . . . . . . . . . . . . 8
6. Comparison of stateless and statefull modes . . . . . . . . . 9
7. Discovery . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7.1. Join-Proxy discovers Registrar . . . . . . . . . . . . . 11
7.1.1. CoAP discovery . . . . . . . . . . . . . . . . . . . 11
7.1.2. Autonomous Network . . . . . . . . . . . . . . . . . 11
7.1.3. 6tisch discovery . . . . . . . . . . . . . . . . . . 11
7.2. Pledge discovers Join Proxy . . . . . . . . . . . . . . . 12
7.2.1. Autonomous Network . . . . . . . . . . . . . . . . . 12
7.2.2. CoAP discovery . . . . . . . . . . . . . . . . . . . 12
7.2.3. 6tisch discovery . . . . . . . . . . . . . . . . . . 12
7.3. Join Proxy discovers Registrar join port . . . . . . . . 12
7.3.1. CoAP discovery . . . . . . . . . . . . . . . . . . . 12
8. Security Considerations . . . . . . . . . . . . . . . . . . . 13
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
9.1. Resource Type registry . . . . . . . . . . . . . . . . . 13
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 14
12. Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . 14
12.1. 02 to 03 . . . . . . . . . . . . . . . . . . . . . . . . 14
12.2. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . 14
12.3. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . 14
12.4. 00 to 00 . . . . . . . . . . . . . . . . . . . . . . . . 14
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
13.1. Normative References . . . . . . . . . . . . . . . . . . 15
13.2. Informative References . . . . . . . . . . . . . . . . . 16
Appendix A. Stateless Proxy payload examples . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
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1. Introduction
Enrolment of new nodes into networks with enrolled nodes present is
described in [RFC8995] ("BRSKI") and makes use of Enrolment over
Secure Transport (EST) [RFC7030] with [RFC8366] vouchers to securely
enroll devices. BRSKI connects a new joining device (called Pledge)
to "Registrars" via a Join Proxy.
The specified solutions use https and may be too large in terms of
code space or bandwidth required for constrained devices.
Constrained devices possibly part of constrained networks [RFC7228]
typically implement the IPv6 over Low-Power Wireless personal Area
Networks (6LoWPAN) [RFC4944] and Constrained Application Protocol
(CoAP) [RFC7252].
CoAP can be run with the Datagram Transport Layer Security (DTLS)
[RFC6347] as a security protocol for authenticity and confidentiality
of the messages. This is known as the "coaps" scheme. A constrained
version of EST, using Coap and DTLS, is described in
[I-D.ietf-ace-coap-est]. The [I-D.ietf-anima-constrained-voucher]
extends [I-D.ietf-ace-coap-est] with BRSKI artefacts such as voucher,
request voucher, and the protocol extensions for constrained Pledges.
DTLS is a client-server protocol relying on the underlying IP layer
to perform the routing between the DTLS Client and the DTLS Server.
However, the new Pledge will not be IP routable until it is
authenticated to the network. A new Pledge can only initially use a
link-local IPv6 address to communicate with a neighbour on the same
link [RFC6775] until it receives the necessary network configuration
parameters. However, before the Pledge can receive these
configuration parameters, it needs to authenticate itself to the
network to which it connects.
During enrollment, a DTLS connection is required between Pledge and
Registrar.
This document specifies a new form of Join Proxy and protocol to act
as intermediary between Pledge and Registrar to relay DTLS messages
between Pledge and Registrar. Two versions of the Join Proxy are
specified:
1 A stateful Join Proxy that locally stores IP addresses
during the connection.
2 A stateless Join Proxy that where the connection state
is stored in the messages.
This document is very much inspired by text published earlier in
[I-D.kumar-dice-dtls-relay].
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[I-D.richardson-anima-state-for-joinrouter] outlined the various
options for building a join proxy. [RFC8995] adopted only the
Circuit Proxy method (1), leaving the other methods as future work.
This document standardizes the CoAP/DTLS (method 4).
2. Terminology
The following terms are defined in [RFC8366], and are used
identically as in that document: artifact, imprint, domain, Join
Registrar/Coordinator (JRC), Manufacturer Authorized Signing
Authority (MASA), Pledge, Trust of First Use (TOFU), and Voucher.
The term "installation network" refers to all devices in the
installation and the network connections between them. The term
"installation IP_address" refers to the set of adresses which are
routable over the whole installation network.
3. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
4. Join Proxy functionality
As depicted in the Figure 1, the Pledge (P), in an LLN mesh can be
more than one hop away from the Registrar (R) and not yet
authenticated into the network.
In this situation, the Pledge can only communicate one-hop to its
nearest neighbour, the Join Proxy (J) using their link-local IPv6
addresses. However, the Pledge (P) needs to communicate with end-to-
end security with a Registrar to authenticate and get the relevant
system/network parameters. If the Pledge (P), knowing the IP-address
of the Registrar, initiates a DTLS connection to the Registrar, then
the packets are dropped at the Join Proxy (J) since the Pledge (P) is
not yet admitted to the network or there is no IP routability to
Pledge (P) for any returned messages from the Registrar.
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++++ multi-hop
|R |---- mesh +--+ +--+
| | \ |J |........|P |
++++ \-----| | | |
+--+ +--+
Registrar Join Proxy Pledge
Figure 1: multi-hop enrolment.
Without routing the Pledge (P) cannot establish a secure connection
to the Registrar (R) over multiple hops in the network.
Furthermore, the Pledge (P) cannot discover the IP address of the
Registrar (R) over multiple hops to initiate a DTLS connection and
perform authentication.
To overcome the problems with non-routability of DTLS packets and/or
discovery of the destination address of the Registrar, the Join Proxy
is introduced. This Join Proxy functionality is configured into all
authenticated devices in the network which may act as a Join Proxy
for Pledges. The Join Proxy allows for routing of the packets from
the Pledge using IP routing to the intended Registrar. An
authenticated Join Proxy can discover the routable IP address of the
Registrar over multiple hops. The following Section 5 specifies the
two Join Proxy modes. A comparison is presented in Section 6.
5. Join Proxy specification
A Join Proxy can operate in two modes:
o Statefull mode
o Stateless mode
A Join Proxy MUST implement one of the two modes. A Join Proxy MAY
implement both, with an unspecified mechanism to switch between the
two modes.
5.1. Statefull Join Proxy
In stateful mode, the Join Proxy forwards the DTLS messages to the
Registrar.
Assume that the Pledge does not know the IP address of the Registrar
it needs to contact. The Join Proxy has has been enrolled via the
Registrar and learns the IP address and port of the Registrar, for
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example by using the discovery mechanism described in Section 7. The
Pledge first discovers (see Section 7) and selects the most
appropriate Join Proxy. (Discovery can also be based upon [RFC8995]
section 4.1, or via DNS-SD service discovery [RFC6763]). The Pledge
initiates its request as if the Join Proxy is the intended Registrar.
The Join Proxy receives the message at a discoverable "Join" port.
The Join Proxy constructs an IP packet by copying the DTLS payload
from the message received from the Pledge, and provides source and
destination addresses to forward the message to the intended
Registrar. The Join Proxy maintains a 4-tuple array to translate the
DTLS messages received from the Registrar and forward it back to the
Pledge.
In Figure 2 the various steps of the message flow are shown, with
5684 being the standard coaps port:
+------------+------------+-------------+--------------------------+
| Pledge | Join Proxy | Registrar | Message |
| (P) | (J) | (R) | Src_IP:port | Dst_IP:port|
+------------+------------+-------------+-------------+------------+
| --ClientHello--> | IP_P:p_P | IP_Ja:p_J |
| --ClientHello--> | IP_Jb:p_Jb| IP_R:5684 |
| | | |
| <--ServerHello-- | IP_R:5684 | IP_Jb:p_Jb |
| : | | |
| <--ServerHello-- : | IP_Ja:p_J | IP_P:p_P |
| : : | | |
| [DTLS messages] | : | : |
| : : | : | : |
| --Finished--> : | IP_P:p_P | IP_Ja:p_J |
| --Finished--> | IP_Jb:p_Jb| IP_R:5684 |
| | | |
| <--Finished-- | IP_R:5684 | IP_Jb:p_Jb |
| <--Finished-- | IP_Ja:p_J | IP_P:p_P |
| : : | : | : |
+---------------------------------------+-------------+------------+
IP_P:p_P = Link-local IP address and port of Pledge (DTLS Client)
IP_R:5684 = Routable IP address and coaps port of Registrar
IP_Ja:P_J = Link-local IP address and join port of Join Proxy
IP_Jb:p_Rb = Routable IP address and client port of Join proxy
Figure 2: constrained statefull joining message flow with Registrar
address known to Join Proxy.
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5.2. Stateless Join Proxy
The stateless Join Proxy aims to minimize the requirements on the
constrained Join Proxy device. Stateless operation requires no
memory in the Join Proxy device, but may also reduce the CPU impact
as the device does not need to search through a state table.
If an untrusted Pledge that can only use link-local addressing wants
to contact a trusted Registrar, and the Registrar is more than one
hop away, it sends its DTLS messages to the Join Proxy.
When a Pledge attempts a DTLS connection to the Join Proxy, it uses
its link-local IP address as its IP source address. This message is
transmitted one-hop to a neighbouring (Join Proxy) node. Under
normal circumstances, this message would be dropped at the neighbour
node since the Pledge is not yet IP routable or is not yet
authenticated to send messages through the network. However, if the
neighbour device has the Join Proxy functionality enabled, it routes
the DTLS message to its Registrar of choice.
The Join Proxy sends a "new" JPY message which includes the DTLS data
as payload.
The JPY message payload consists of two parts:
o Header (H) field: consisting of the source link-local address and
port of the Pledge (P), and
o Contents (C) field: containing the original DTLS payload.
On receiving the JPY message, the Registrar (or proxy) retrieves the
two parts.
The Registrar transiently stores the Header field information. The
Registrar uses the Contents field to execute the Registrar
functionality. However, when the Registrar replies, it also extends
its DTLS message with the header field in a JPY message and sends it
back to the Join Proxy. The Registrar SHOULD NOT assume that it can
decode the Header Field, it should simply repeat it when responding.
The Header contains the original source link-local address and port
of the Pledge from the transient state stored earlier and the
Contents field contains the DTLS payload.
On receiving the JPY message, the Join Proxy retrieves the two parts.
It uses the Header field to route the DTLS message containing the
DTLS payload retrieved from the Contents field to the Pledge.
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In this scenario, both the Registrar and the Join Proxy use
discoverable "Join" ports, which may be the default ports.
The Figure 3 depicts the message flow diagram:
+--------------+------------+---------------+-----------------------+
| Pledge | Join Proxy | Registrar | Message |
| (P) | (J) | (R) |Src_IP:port|Dst_IP:port|
+--------------+------------+---------------+-----------+-----------+
| --ClientHello--> | IP_P:p_P |IP_Ja:p_Ja |
| --JPY[H(IP_P:p_P),--> | IP_Jb:p_Jb|IP_R:p_Ra |
| C(ClientHello)] | | |
| <--JPY[H(IP_P:p_P),-- | IP_R:p_Ra |IP_Jb:p_Jb |
| C(ServerHello)] | | |
| <--ServerHello-- | IP_Ja:p_Ja|IP_P:p_P |
| : | | |
| [ DTLS messages ] | : | : |
| : | : | : |
| --Finished--> | IP_P:p_P |IP_Ja:p_Ja |
| --JPY[H(IP_P:p_P),--> | IP_Jb:p_Jb|IP_R:p_Ra |
| C(Finished)] | | |
| <--JPY[H(IP_P:p_P),-- | IP_R:p_Ra |IP_Jb:p_Jb |
| C(Finished)] | | |
| <--Finished-- | IP_Ja:p_Ja|IP_P:p_P |
| : | : | : |
+-------------------------------------------+-----------+-----------+
IP_P:p_P = Link-local IP address and port of the Pledge
IP_R:p_Ra = Routable IP address and join port of Registrar
IP_Ja:p_Ja = Link-local IP address and join port of Join Proxy
IP_Jb:p_Jb = Routable IP address and port of Join Proxy
JPY[H(),C()] = Join Proxy message with header H and content C
Figure 3: constrained stateless joining message flow.
5.3. Stateless Message structure
The JPY message is constructed as a payload with media-type
aplication/cbor
Header and Contents fields togther are one cbor array of 5 elements:
1. header field: containing a CBOR array [RFC7049] with the Pledge
IPv6 Link Local address as a cbor byte string, the Pledge's UDP
port number as a CBOR integer, the IP address family (IPv4/IPv6)
as a cbor integer, and the proxy's ifindex or other identifier
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for the physical port as cbor integer. The header field is not
DTLS encrypted.
2. Content field: containing the DTLS payload as a CBOR byte string.
The join_proxy cannot decrypt the DTLS payload and has no knowledge
of the transported media type.
JPY_message =
[
ip : bstr,
port : int,
family : int,
index : int
payload : bstr
]
Figure 4: CDDL representation of JPY message
The content fields are DTLS encrypted. In CBOR diagnostic notation
the payload JPY[H(IP_P:p_P)], will look like:
[h'IP_p', p_P, family, ident, h'DTLS-payload']
Examples are shown in Appendix A.
6. Comparison of stateless and statefull modes
The stateful and stateless mode of operation for the Join Proxy have
their advantages and disadvantages. This section should enable to
make a choice between the two modes based on the available device
resources and network bandwidth.
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+-------------+----------------------------+------------------------+
| Properties | Stateful mode | Stateless mode |
+-------------+----------------------------+------------------------+
| State |The Join Proxy needs | No information is |
| Information |additional storage to | maintained by the Join |
| |maintain mapping between | Proxy. Registrar needs |
| |the address and port number | to store the packet |
| |of the Pledge and those | header. |
| |of the Registrar. | |
+-------------+----------------------------+------------------------+
|Packet size |The size of the forwarded |Size of the forwarded |
| |message is the same as the |message is bigger than |
| |original message. |the original,it includes|
| | |additional IP-addresses |
+-------------+----------------------------+------------------------+
|Specification|The Join Proxy needs |New JPY message to |
|complexity |additional functionality |encapsulate DTLS payload|
| |to maintain state |The Registrar |
| |information, and specify |and the Join Proxy |
| |the source and destination |have to understand the |
| |addresses of the DTLS |JPY message in order |
| |handshake messages |to process it. |
+-------------+----------------------------+------------------------+
| Ports | Join Proxy needs |Join Proxy and Registrar|
| | discoverable "Join" port |need discoverable |
| | | "Join" ports |
+-------------+----------------------------+------------------------+
Figure 5: Comparison between stateful and stateless mode
7. Discovery
It is assumed that Join Proxy seamlessly provides a coaps connection
between Pledge and Registrar. In particular this section replaces
section 4.1 of [RFC8995].
The discovery follows two steps with two alternatives for step 1:
1. Two alternatives:
a. The Pledge is one hop away from the Registrar. The Pledge
discovers the link-local address of the Registrar as described in
[I-D.ietf-ace-coap-est]. From then on, it follows the BRSKI process
as described in [I-D.ietf-ace-coap-est] and
[I-D.ietf-anima-constrained-voucher], using link-local addresses.
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b. The Pledge is more than one hop away from a relevant Registrar,
and discovers the link-local address and join port of a Join Proxy.
The Pledge then follows the BRSKI procedure using the link-local
address of the Join Proxy.
1. Once enrolled, the Join Proxy discovers the join port of the
Registrar.
Once a Pledge is enrolled, it may function as Join Proxy. The Join
Proxy functions are advertised as descibed below. In principle, the
Join Proxy functions are offered via a "join" port, and not the
standard coaps port. Also the Registrar offers a "join" port to
which the stateless join proxy sends the JPY message. The Join Proxy
and Registrar show the extra join port number when reponding to a
/.well-known/core discovery request addressed to the standard coap/
coaps port.
Three discovery cases are discussed: Join_proxy discovers Registrar,
Pledge discovers Registrar, and Pledge discovers Join-proxy. Each
discovery case considers threa alternatives: coap discovery, 6tisch
discovery and GRASP discovery.
7.1. Join-Proxy discovers Registrar
In this section, the Pledge and Join Proxy are assumed to communicate
via Link-Local addresses. This section describes the discovery of
the Registrar by the Join-Proxy.
7.1.1. CoAP discovery
The discovery of the coaps Registrar, using coap discovery, by the
Join Proxy follows section 6 of [I-D.ietf-ace-coap-est].
7.1.2. Autonomous Network
In the context of autonomous networks, the Join Proxy uses the DULL
GRASP M_FLOOD mechanism to announce itself. Section 4.1.1 of
[RFC8995] discusses this in more detail. The Registrar announces
itself using ACP instance of GRASP using M_FLOOD messages.
Autonomous Network Join Proxies MUST support GRASP discovery of
Registrar as decribed in section 4.3 of [RFC8995] .
7.1.3. 6tisch discovery
The discovery of Registrar by the Join-Proxy uses the enhanced
beacons as discussed in [I-D.ietf-6tisch-enrollment-enhanced-beacon].
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7.2. Pledge discovers Join Proxy
7.2.1. Autonomous Network
The Pledge MUST listen for GRASP M_FLOOD [I-D.ietf-anima-grasp]
announcements of the objective: "AN_Proxy". See section
Section 4.1.1 [RFC8995] for the details of the objective.
7.2.2. CoAP discovery
In the context of a coap network without Autonomous Network support,
discovery follows the standard coap policy. The Pledge can discover
a Join Proxy by sending a link-local multicast message to ALL CoAP
Nodes with address FF02::FD. Multiple or no nodes may respond. The
handling of multiple responses and the absence of responses follow
section 4 of [RFC8995].
The join port of the Join Proxy is discovered by sending a GET
request to "/.well-known/core" including a resource type (rt)
parameter with the value "brski-proxy" [RFC6690]. Upon success, the
return payload will contain the join port.
The example below shows the discovery of the join port of the Join
Proxy.
REQ: GET coap://[FF02::FD]/.well-known/core?rt=brski-proxy
RES: 2.05 Content
<coaps://[IP_address]:join-port>; rt="brski-proxy"
Port numbers are assumed to be the default numbers 5683 and 5684 for
coap and coaps respectively (sections 12.6 and 12.7 of [RFC7252] when
not shown in the response. Discoverable port numbers are usually
returned for Join Proxy resources in the <href> of the payload (see
section 5.1 of [I-D.ietf-ace-coap-est]).
7.2.3. 6tisch discovery
Not applicable.
7.3. Join Proxy discovers Registrar join port
7.3.1. CoAP discovery
The stateless Join Proxy can discover the join port of the Registrar
by sending a GET request to "/.well-known/core" including a resource
type (rt) parameter with the value "join-proxy" [RFC6690]. Upon
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success, the return payload will contain the join Port of the
Registrar.
REQ: GET coap://[IP_address]/.well-known/core?rt=join-proxy
RES: 2.05 Content
<coaps://[IP_address]:join-port>; rt="join-proxy"
The discoverable port numbers are usually returned for Join Proxy
resources in the <href> of the payload (see section 5.1 of
[I-D.ietf-ace-coap-est]).
8. Security Considerations
It should be noted here that the contents of the CBOR map used to
convey return address information is not protected. However, the
communication is between the Proxy and a known registrar are over the
already secured portion of the network, so are not visible to
eavesdropping systems.
All of the concerns in [RFC8995] section 4.1 apply. The Pledge can
be deceived by malicious Join_Proxy announcements. The Pledge will
only join a network to which it receives a valid [RFC8366] voucher
[I-D.ietf-anima-constrained-voucher].
If the communicatione between Join-Proxy and Registrar passed over an
unsecure network, then an attacker could change the cbor array,
causing the Pledge to send traffic to another node. If the such
scenario needed to be supported, then it would be reasonable for the
Proxy to encrypt the CBOR array using a locally generated symmetric
key. The Registrar would not be able to examine the result, but it
does not need to do so. This is a topic for future work.
9. IANA Considerations
This document needs to create a registry for key indices in the CBOR
map. It should be given a name, and the amending formula should be
IETF Specification.
9.1. Resource Type registry
This specification registers a new Resource Type (rt=) Link Target
Attributes in the "Resource Type (rt=) Link Target Attribute Values"
subregistry under the "Constrained RESTful Environments (CoRE)
Parameters" registry.
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rt="brski-proxy". This BRSKI resource is used to query and return
the supported BRSKI port of the Join Proxy.
rt="join-proxy". This BRSKI resource is used to query and return
the supported BRSKI port of the Registrar.
10. Acknowledgements
Many thanks for the comments by Brian Carpenter and Esko Dijk.
11. Contributors
Sandeep Kumar, Sye loong Keoh, and Oscar Garcia-Morchon are the co-
authors of the draft-kumar-dice-dtls-relay-02. Their draft has
served as a basis for this document. Much text from their draft is
copied over to this draft.
12. Changelog
12.1. 02 to 03
* Terminology updated
* Several clarifications on discovery and routability
* DTLS payload introduced
12.2. 01 to 02
o Discovery of Join Proxy and Registrar ports
12.3. 00 to 01
o Registrar used throughout instead of EST server
o Emphasized additional Join Proxy port for Join Proxy and Registrar
o updated discovery accordingly
o updated stateless Join Proxy JPY header
o JPY header described with CDDL
o Example simplified and corrected
12.4. 00 to 00
o copied from vanderstok-anima-constrained-join-proxy-05
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13. References
13.1. Normative References
[I-D.ietf-6tisch-enrollment-enhanced-beacon]
(editor), D. D. and M. Richardson, "Encapsulation of
6TiSCH Join and Enrollment Information Elements", draft-
ietf-6tisch-enrollment-enhanced-beacon-14 (work in
progress), February 2020.
[I-D.ietf-ace-coap-est]
Stok, P. V. D., Kampanakis, P., Richardson, M. C., and S.
Raza, "EST over secure CoAP (EST-coaps)", draft-ietf-ace-
coap-est-18 (work in progress), January 2020.
[I-D.ietf-anima-constrained-voucher]
Richardson, M., Stok, P. V. D., Kampanakis, P., and E.
Dijk, "Constrained Voucher Artifacts for Bootstrapping
Protocols", draft-ietf-anima-constrained-voucher-13 (work
in progress), July 2021.
[I-D.ietf-anima-grasp]
Bormann, C., Carpenter, B., and B. Liu, "GeneRic Autonomic
Signaling Protocol (GRASP)", draft-ietf-anima-grasp-15
(work in progress), July 2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <https://www.rfc-editor.org/info/rfc6347>.
[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
October 2013, <https://www.rfc-editor.org/info/rfc7049>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8366] Watsen, K., Richardson, M., Pritikin, M., and T. Eckert,
"A Voucher Artifact for Bootstrapping Protocols",
RFC 8366, DOI 10.17487/RFC8366, May 2018,
<https://www.rfc-editor.org/info/rfc8366>.
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[RFC8995] Pritikin, M., Richardson, M., Eckert, T., Behringer, M.,
and K. Watsen, "Bootstrapping Remote Secure Key
Infrastructure (BRSKI)", RFC 8995, DOI 10.17487/RFC8995,
May 2021, <https://www.rfc-editor.org/info/rfc8995>.
13.2. Informative References
[I-D.kumar-dice-dtls-relay]
Kumar, S. S., Keoh, S. L., and O. Garcia-Morchon, "DTLS
Relay for Constrained Environments", draft-kumar-dice-
dtls-relay-02 (work in progress), October 2014.
[I-D.richardson-anima-state-for-joinrouter]
Richardson, M. C., "Considerations for stateful vs
stateless join router in ANIMA bootstrap", draft-
richardson-anima-state-for-joinrouter-03 (work in
progress), September 2020.
[RFC4944] Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,
"Transmission of IPv6 Packets over IEEE 802.15.4
Networks", RFC 4944, DOI 10.17487/RFC4944, September 2007,
<https://www.rfc-editor.org/info/rfc4944>.
[RFC6690] Shelby, Z., "Constrained RESTful Environments (CoRE) Link
Format", RFC 6690, DOI 10.17487/RFC6690, August 2012,
<https://www.rfc-editor.org/info/rfc6690>.
[RFC6763] Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", RFC 6763, DOI 10.17487/RFC6763, February 2013,
<https://www.rfc-editor.org/info/rfc6763>.
[RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C.
Bormann, "Neighbor Discovery Optimization for IPv6 over
Low-Power Wireless Personal Area Networks (6LoWPANs)",
RFC 6775, DOI 10.17487/RFC6775, November 2012,
<https://www.rfc-editor.org/info/rfc6775>.
[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030,
DOI 10.17487/RFC7030, October 2013,
<https://www.rfc-editor.org/info/rfc7030>.
[RFC7228] Bormann, C., Ersue, M., and A. Keranen, "Terminology for
Constrained-Node Networks", RFC 7228,
DOI 10.17487/RFC7228, May 2014,
<https://www.rfc-editor.org/info/rfc7228>.
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[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252,
DOI 10.17487/RFC7252, June 2014,
<https://www.rfc-editor.org/info/rfc7252>.
Appendix A. Stateless Proxy payload examples
The examples show the request "GET coaps://192.168.1.200:5965/est/
crts" to a Registrar. The header generated between Join-Proxy and
Registrar and from Registrar to Join-Proxy are shown in detail. The
DTLS payload is not shown.
The request from Join Proxy to Registrar looks like:
85 # array(5)
50 # bytes(16)
FE800000000000000000FFFFC0A801C8 #
19 BDA7 # unsigned(48551)
0A # unsigned(10)
00 # unsigned(0)
58 2D # bytes(45)
<cacrts DTLS encrypted request>
In CBOR Diagnostic:
[h'FE800000000000000000FFFFC0A801C8', 48551, 10, 0,
h'<cacrts DTLS encrypted request>']
The response is:
85 # array(5)
50 # bytes(16)
FE800000000000000000FFFFC0A801C8 #
19 BDA7 # unsigned(48551)
0A # unsigned(10)
00 # unsigned(0)
59 026A # bytes(618)
<cacrts DTLS encrypted response>
In CBOR diagnostic:
[h'FE800000000000000000FFFFC0A801C8', 48551, 10, 0,
h'<cacrts DTLS encrypted response>']
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Authors' Addresses
Michael Richardson
Sandelman Software Works
Email: mcr+ietf@sandelman.ca
Peter van der Stok
vanderstok consultancy
Email: consultancy@vanderstok.org
Panos Kampanakis
Cisco Systems
Email: pkampana@cisco.com
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