Extensible Provisioning Protocol (EPP) Transport over QUIC

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Table of Contents

2. Terminology

This document makes use of the following terms:¶

EoQ:

The acronym used for the EPP over QUIC transport that defines the use of QUIC as an EPP transport following the considerations in Section 2.1 of [RFC5730].¶

EoQ connection:

Is a client-initiated bidirectional QUIC stream established on a QUIC connection using the "EoQ" Application-Layer Protocol Negotiation (ALPN) [RFC7301] value. The EoQ connection maps to the client-server connection defined in Section 2.1 of [RFC5730], where the server returns an EPP <greeting>. A single QUIC connection supports many EoQ connections.¶

EoQ session:

Is an authenticated EoQ connection, which occurs after a successful EPP <login>.¶

EoQ Connection Start Packet:

Used by clients to complete the creation of an EoQ connection by signaling the server to create the QUIC stream and return the EPP <greeting> needed for an EPP connection. Section 6 formally defines the EoQ Connection Start Packet.¶

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.¶

3. Session Management

Mapping EPP session management facilities onto the QUIC service is accomplished with a combination of a QUIC connection with the "EoQ" ALPN [RFC7301] value and client-initiated, bidirectional QUIC streams. QUIC supports four stream types (Section 2.1 of [RFC9000]), but EoQ only supports the client-initiated, bidirectional stream type.¶

An EPP session first requires creation of a QUIC connection between two peers, one that initiates the connection request and one that responds to the connection request. The initiating peer is called the "client", and the responding peer is called the "server". By default, an EPP server MUST listen for QUIC connection requests on a well-known UDP port number assigned by IANA (see Section 8.2), unless there is a mutual agreement to use another port number.¶

A successfully established QUIC connection is secured by the native TLS support that QUIC provides using the "EoQ" ALPN value.¶

Once the QUIC connection is established, the EPP client MUST then create a bidirectional QUIC stream by sending the EoQ Connection Start Packet (Section 6). [RFC9000] states that "streams are created by sending data". If the EPP server accepts the QUIC stream, it reads the EoQ Connection Start Packet (Section 6) and returns an EPP <greeting> to the client on the same QUIC stream. After reading the EPP <greeting> message, and absent processing errors, the EPP client sends EPP commands and receives EPP responses on the same stream. A QUIC stream corresponds to an EPP connection, which is referred to as an EoQ connection. An authenticated QUIC stream, via a successful EPP <login>, corresponds to an EPP session, which is referred to as an EoQ session.¶

An EPP session is normally ended by the client issuing an EPP <logout> command. A server receiving an EPP <logout> command MUST end the EPP session and close the QUIC stream. A client MAY end an EoQ session by closing the QUIC stream and the server MUST end the EoQ session by closing the QUIC stream.¶

EoQ connections are established as described in the QUIC transport specification [RFC9000]. During connection establishment, EoQ support is indicated using the "EoQ" ALPN value in the cryptographic handshake.¶

A single QUIC connection may allow multiple QUIC streams. This means that a single QUIC connection may support multiple EoQ sessions. A server MAY limit the life span of an established EoQ session. EoQ sessions that are inactive for more than a server-defined period MAY be ended by the server closing the QUIC stream. A server MAY close EoQ sessions that have been open and active for longer than a server-defined limit. Once the last QUIC stream for a QUIC connection is closed, the server MAY end the QUIC connection immediately.¶

5. Data Unit Format

The EPP data unit contains two fields: a 32-bit header that describes the total length of the data unit, and the EPP XML instance. The length of the EPP XML instance is determined by subtracting four octets from the total length of the data unit. A receiver must successfully read that many octets to retrieve the complete EPP XML instance before processing the EPP message. The EPP Data Unit Format is depicted in Figure 2 (one tick mark represents one bit position).¶

     0                   1                   2                   3
     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                           Total Length                        |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                         EPP XML Instance                      |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+//-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                          Figure 2: EPP Data Unit Format

The description of the fields shown in Figure 2 is as follows:

Total Length (32 bits): The total length of the EPP data unit measured in octets in network (big endian) byte order. The octets contained in this field MUST be included in the total length calculation. EPP XML Instance (variable length): The EPP XML instance carried in the data unit.¶

6. EoQ Connection Start Packet

The EoQ Connection Start Packet is written by the client after creating a QUIC stream to signal to the server to create the QUIC stream. Absent processing errors or local policy, the server accepts the QUIC stream, reads the EoQ Connection Start Packet, and returns the EPP <greeting> to the client on same QUIC stream.¶

The EoQ Connection Start Packet follows the Data Unit Format (Section 5) with two fields: a 32-bit header that describes the total length of the data unit, and the constant value of "EoQ Connection Start" instead of an "EPP XML Instance". The length of a valid data unit MUST be 24 octets that includes 4 octets for the Total Length and 20 octets for the "EoQ Connection Start" constant value.¶

8. IANA Considerations

RFC Editor Note: Please replace all occurrences of XXXX with the RFC number to be assigned to this document.¶

9. Implementation Status

Note to RFC Editor: Please remove this section and the reference to RFC 7942 [RFC7942] before publication.¶

This section records the status of known implementations of the protocol defined by this specification at the time of posting of this Internet-Draft, and is based on a proposal described in RFC 7942 [RFC7942]. The description of implementations in this section is intended to assist the IETF in its decision processes in progressing drafts to RFCs. Please note that the listing of any individual implementation here does not imply endorsement by the IETF. Furthermore, no effort has been spent to verify the information presented here that was supplied by IETF contributors. This is not intended as, and must not be construed to be, a catalog of available implementations or their features. Readers are advised to note that other implementations may exist.¶

According to RFC 7942 [RFC7942], "this will allow reviewers and working groups to assign due consideration to documents that have the benefit of running code, which may serve as evidence of valuable experimentation and feedback that have made the implemented protocols more mature. It is up to the individual working groups to use this information as they see fit".¶

10. Operational Considerations

11. Security Considerations

EPP over QUIC provides the similar security with EPP over TCP with TLS. Some related security issues have been discussed in [RFC5734] and [RFC9000].¶

EoQ servers run the risk of a resource exhaustion attack by allowing the creation of unlimited QUIC streams per QUIC connection. Servers SHOULD limit a client to a maximum number of QUIC streams per QUIC connection based on server capabilities and operational load. Absent such limit, the server may be subject to overload that would exhaust its resources.¶

12. Acknowledgements

The authors wish to thank the following persons for their feedback and suggestions: Scott Hollenbeck, Lucas Pardue, Martin Thompson, and Mohamed Boucadair.¶

Authors' Addresses