UCLouvain

maxime.piraux@uclouvain.be

UCLouvain

olivier.bonaventure@uclouvain.be

Apple Inc.

adi@apple.com

Transport QUIC Working Group Internet-Draft This document specifies methods for tunneling Ethernet frames and Internet protocols such as TCP, UDP, IP and QUIC inside a QUIC connection.

Mobile devices such as laptops, smartphones or tablets have different requirements than the traditional fixed devices. These mobile devices often change their network attachment. They are often attached to trusted networks, but sometimes they need to be connected to untrusted networks where their communications can be eavesdropped, filtered or modified. In these situations, the classical approach is to rely on VPN protocols such as DTLS or IPSec. These VPN protocols provide the encryption and authentication functions to protect those mobile clients from malicious behaviors in untrusted networks. However, some networks have deployed filters that block these VPN protocols. When faced with such filters, users can either switch off their connection or find alternatives, e.g. by using TLS to access some services over TCP port 443. The planned deployment of QUIC opens a new opportunity for such users. Since QUIC will be used to access web sites, it should be less affected by filters than VPN solutions such as IPSec or DTLS. Furthermore, the flexibility of QUIC makes it possible to easily extend the protocol to support VPN services. This document shares some goals with the MASQUE framework . The proposed QUIC tunnel protocol contributes to the effort of defining a signaling for conveying multiple proxied flows inside a QUIC connection. While this document specifies its own protocol, further work could adapt the mechanisms presented in this proposal to use HTTP/3. On the other hand, today's mobile devices are often multihomed and many expect to be able to perform seamless handovers from one access network to another without breaking the established VPN sessions. In some situations it can also be beneficial to combine two or more access networks together to increase the available host bandwidth. A protocol such as Multipath TCP supports those handovers and allows aggregating the bandwidth of different access links. It could be combined with single-path VPN protocols to support both seamless handovers and bandwidth aggregation above VPN tunnels. Unfortunately, Multipath TCP is not yet deployed on most Internet servers and thus few applications would benefit from such a use case. In this document, we explore how QUIC could be used to enable multi-homed mobile devices to communicate securely in untrusted networks. The QUIC protocol opens up a new way to find a clean solution to this problem. First, QUIC includes the same encryption and authentication techniques as deployed VPN protocols. Second, QUIC is intended to be widely used to support web-based services, making it unlikely to be filtered in many networks, in contrast with VPN protocols. Third, the QUIC migration mechanism enables handovers between several network interfaces. This document is organized as follows. describes our reference environment. Then, we propose two mode of operations, explained in and , that use the recently proposed datagram extension () for QUIC to transport plain IP packets over a QUIC connection. specifies how a connection is established in this document proposal. details the format of the messages introduced by this document.

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 when, and only when, they appear in all capitals, as shown here.

Our first scenario is a client that uses a QUIC tunnel to send all its packets to a concentrator. The concentrator decrypts the packets received over the QUIC connection and forwards them to their final destination. It also receives the packets destined to the client and tunnels them through the QUIC connection.

| destination | +--------+ +--------------+ | server | ^ +---------+ ^ +-------------+ | | Access | | | | network | | Legend: .----| |----. --- QUIC connection +---------+ === TCP/UDP flow ]]>

However, there are several situations where the client is attached to two or more access networks. This client can be multihomed, dual-stack, … This is illustrated in , in which a client-initiated flow is tunneled through the concentrator. We also discuss inbound connections in this document in .

| destination | +--------+ +--------------+ | server | ^ +---------+ ^ +-------------+ | | Access | | | | network | | Legend: .----| B |----. --- QUIC connection +---------+ === TCP/UDP flow ]]>

Such a client would like to benefit from the different access networks available to reach the concentrator. These access networks can be used for load-sharing, failover or other purposes. One possibility to efficiently use these two access networks is to rely on the proposed Multipath extensions to QUIC . Another approach is to create one QUIC connection using the single-path QUIC protocol over each access network and glue these different sessions together on the concentrator. Given the migration capabilities of QUIC, this approach could support failover with a single active QUIC connection at a time. In a nutshell, the solution proposed in this document works as follows. The client opens a QUIC connection to a concentrator. The concentrator authenticates the client through means that are outside the scope of this document such as client certificates, usernames/passwords, OAuth, … If the authentication succeeds, the client can use the tunnel to exchange Ethernet frames and IP packets with the concentrator over the QUIC session. If the client uses IP, then the concentrator can allocate an IP address to the client at the end of the authentication phase. The client can then send packets via the concentrator by tunneling them through the concentrator. The concentrator captures the IP packets destined to the client and tunnels them over the QUIC connection. Our solution is intended to provide a similar service as the one provided by IPSec tunnels or DTLS.

Our first mode of operation is very simple. It leverages the recently proposed QUIC datagram extension . In a nutshell, to send a packet to a remote host, the client simply encodes the entire packet inside a QUIC DATAGRAM frame sent over the QUIC connection established with the concentrator. This QUIC DATAGRAM frame is then encrypted and authenticated in a QUIC packet. This transmission is subject to congestion control, but the frame that contains the packet is not retransmitted in case of losses as specified in . This mode adds a minimal byte overhead for packet encapsulation in QUIC. It does not define ways of indicating the protocol of the conveyed packets, which can be useful in deployments for which out-of-band signalling can be used.

Our second mode of operation, called the datagram mode in this document, enables the client and the concentrator to exchange packets of several network protocols through the QUIC tunnel connection at the same time. It also leverages the QUIC datagram extension . This document specifies the following format for encoding packets in QUIC DATAGRAM frame. It allows encoding packets from several protocols by identifying the corresponding protocol of the packet in each QUIC DATAGRAM frame. describes this encoding.

This encoding defines three fields. Protocol Type: The Protocol Type field contains the protocol type of the payload packet. The values for the different protocols are defined as "ETHER TYPES" in . A QUIC tunnel that receives a Protocol Type representing an unsupported protocol MAY drop the associated Packet. QUIC tunnel endpoints willing to exchange Ethernet frames can use the value 0x6558 for . Packet Tag: An opaque 16-bit value. The QUIC tunnel application is free to decide its semantic value. For instance, a QUIC tunnel endpoint MAY encode the sending order of packets in the Packet Tag, e.g. as a timestamp or a sequence number, to allow reordering on the receiver. Packet: The packet conveyed inside the QUIC tunnel connection.

+----------+ | | IP | QUIC packet | +----------+ containing | | UDP | a DATAGRAM | +----------+ frame | | QUIC | | |..........| | | DATAGRAM | | | P. Type | | | P. Tag | | |+--------+|<-. | || IP || | | |+--------+| | Tunneled | || UDP || | UDP packet | |+--------+| | | | .... |<-. `->+----------+ ]]>

illustrates how a UDP packet is tunneled using the datagram mode. The main advantage of the datagram mode is that it supports IP and any protocol above the network layer. Any IP packet can be transported using the datagram extension over a QUIC connection. However, this advantage comes with a large per-packet overhead since each packet contains both a network and a transport header. All these headers must be transmitted in addition with the IP/UDP/QUIC headers of the QUIC connection. For TCP connections for instance, the per-packet overhead can be large.

If the client is multihomed, it can use Multipath QUIC to efficiently use its different access networks. This version of the document does not elaborate in details on this possibility. If the concentrator does not support Multipath QUIC, then the client creates several QUIC connections and joins them at the application layer. This works as illustrated in figure . Each message is exchanged over a dedicated unidirectional QUIC stream. Their format is detailed in . When the client opens the first QUIC connection with the concentrator, (1) it can request a QUIC tunnel session identifier. (2) The concentrator replies with a variable-length opaque value that identifies the QUIC tunneling session. When opening a QUIC connection over another access network, (3) the client can send this identifier to join the QUIC tunneling session. The concentrator matches the session identifier with the existing session with the client. It can then use both sessions to reach the client and received tunneled packets from the client.

.-----------------------------. | <-Sess. ID.-2 | v v +--------+ +--------------+ | Client | | Concentrator | +--------+ +--------------+ ^ ^ | 3-Join. Sess.-> | Legend: .-----------------------------. --- QUIC connection ]]>

Joining a tunneling session allows grouping several QUIC connections to the concentrator. Each endpoint can then coordinate the use of the Packet Tag across the tunneling session as presented in . Both QUIC tunnel endpoints open their first unidirectional stream (i.e. stream 2 and 3), hereafter named the QUIC tunnel control stream, to exchange these messages. A QUIC tunnel endpoint MUST NOT close its unidirectional stream and SHOULD provide enough flow control credit to its peer. The messages format used for this purpose are described in . The client initiates the procedure and MAY either start a new session or join an existing session. This negotiation MUST NOT take place more than once per QUIC connection.

When using the datagram mode, each packet is associated with a 16-bit value called Packet Tag. This document leaves defining the meaning of this value to implementations. This section provides some examples on how it can be used to implement packet reordering across several QUIC tunnel connections grouped in a tunneling session. A first simple example of use is to encode the timestamp at which the datagram was sent. Using a millisecond precision and encoding the 16 lower bits of the timestamp makes the value wrapping around in a bit more than 65 seconds. Another example of use is to maintain a value counting the datagrams sent over all QUIC tunnel connections of the tunneling session. The 16-bit value allows distinguishing at most 32768 packets in flight. The QUIC tunnel receiver can then distinguish, buffer and reorder packets based on this value. Mechanisms for managing the datagram buffer and negotiating the use of the Packet Tag are out of scope of this document.

During connection establishment, the QUIC tunnel datagram mode (resp. lite mode) support is indicated by setting the ALPN token "qt" (resp. "qt-lite") in the TLS handshake. Draft-version implementations MAY specify a particular draft version by suffixing the token, e.g. "qt-00" (resp. "qt-lite-03") refers to the first (resp. fourth) version of this document. After the QUIC connection is established, the client can start using the datagram or the stream mode. The client may use PCP to request the concentrator to accept inbound connections on their behalf. After the negotiation of such port mappings, the concentrator can start sending packets containing inbound connections in QUIC DATAGRAM frame.

In the following sections, we specify the format of each message introduced in this document. They are encoded as TLVs, i.e. (Type, Length, Value) tuples, as illustrated in . All TLV fields are encoded in network-byte order.

The Type field is encoded as a byte and identifies the type of the TLV. The Length field is encoded as a byte and indicate the length of the Value field. A value of zero indicates that no Value field is present. The Value field is a type-specific value whose length is determined by the Length field.

This document specifies the following QUIC tunnel control TLVs:

The Access Report TLV is sent by the client to periodically report on access networks availability. Each Access Report TLV MUST be sent on a separate unidirectional stream. When the datagram mode is in use, this separate stream MUST be other than the QUIC tunnel control stream. The New Session TLV is used by the client to initiate a new tunneling session. The Session ID TLV is used by the concentrator to communicate to the client the Session ID identifying this tunneling session. The Join Session TLV is used to join a given tunneling session, identified by a Session ID. All QUIC these tunnel control TLVs MUST NOT be sent on other streams than the QUIC tunnel control streams.

The Access Report TLV contains the following: AI (Access ID) - a four-bit-long field that identifies the access network, e.g., 3GPP (Radio Access Technologies specified by 3GPP) or Non-3GPP (accesses that are not specified by 3GPP) . The value is one of those listed below (all other values are invalid and the TLV that contains it MUST be discarded):

R (Reserved) - a four-bit-long field that MUST be zeroed on transmission and ignored on receipt. Signal - a one-octet-long field that identifies the report signal, e.g., available or unavailable. The value is supplied to the QUIC tunnel through some mechanism that is outside the scope of this document. The value is one of those listed in . The client that includes the Access Report TLV sets the value of the Access ID field according to the type of access network it reports on. Also, the client sets the value of the Signal field to reflect the operational state of the access network. The mechanism to determine the state of the access network is outside the scope of this specification. The client MUST be able to cancel the sending of an Access Report TLV that is pending delivery, i.e. by resetting its corresponding unidirectional stream. This can be used when the information contained in the TLV is no longer relevant, e.g. the access network availability has changed. The time of canceling is based on local policies and network environment. Reporting the unavailability an access network to the concentrator can serve as an advisory signal to preventively stop sending packets over this network while maintaining the QUIC tunnel connection. Upon reporting of the availability of this network, the concentrator can quickly resume sending packets over this network.

The New Session TLV does not contain a value. It initiates a new tunneling session at the concentrator. The concentrator MUST send a Session ID TLV in response, with the Session ID corresponding to the tunneling session created. After sending a New Session TLV, the client MUST close the QUIC tunnel control stream. The concentrator MUST NOT send New Session TLVs.

The Session ID TLV contains an opaque value that identifies the current tunneling session. It can be used by the client in subsequent QUIC connections to join them to this tunneling session. The concentrator MUST send a Session ID TLV in response of a New Session TLV, with the Session ID corresponding to the tunneling session created. The client MUST NOT send a Session ID TLV. The concentrator MUST close the QUIC tunnel control stream after sending a Session ID TLV.

The Join Session TLV contains an opaque value that identifies a tunneling session to join. The client can send a Join Session TLV to join the QUIC connection to a particular tunneling session. The tunneling session is identified by the Session ID. After sending a Join Session TLV, the client MUST close the QUIC tunnel control stream. The concentrator MUST NOT send Join Session TLVs. After receiving a Join Session TLV, the concentrator MUST use the Session ID to join this QUIC connection to the tunneling session. Joining the tunneling session implies merging the state of this QUIC tunnel connection to the session. A successful joining of connection is indicated by the closure of the QUIC tunnel control stream of the concentrator. In cases of failure when joining a tunneling session, the concentrator MUST send a RESET_STREAM with an application error code discerning the cause of the failure. The possible codes are listed below: UNKNOWN_ERROR (0x0): An unknown error occurred when joining the tunneling session. QUIC tunnel endpoints SHOULD use more specific error codes when applicable. UNKNOWN_SESSION_ID (0x1): The Session ID used in the Join Session TLV is not a valid ID. It was not issued in a Session ID TLV or refers to an expired tunneling session. CONFLICTING_STATE (0x2): The current state of the QUIC tunnel connection could not be merged with the tunneling session.

The Concentrator has access to all the packets it processes. It MUST be protected as a core IP router, e.g. as specified in .

Ingress filtering policies MUST be enforced at the network boundaries, i.e. as specified in .

This document creates two new registrations for the identification of the QUIC tunnel protocol in the "Application Layer Protocol Negotiation (ALPN) Protocol IDs" registry established in . The "qt" string identifies the QUIC tunnel protocol datagram mode. QUIC Tunnel 0x71 0x74 ("qt") This document The "qt-lite" string identifies the QUIC tunnel protocol lightweight mode. QUIC Tunnel lightweight mode 0x71 0x74 0x55 0x6c 0x69 0x74 0x65 ("qt-lite") This document

IANA is requested to create a new "QUIC tunnel control Parameters" registry. The following subsections detail new registries within "QUIC tunnel control Parameters" registry.

IANA is request to create the "QUIC tunnel control TLVs Types" sub-registry. New values are assigned via IETF Review (Section 4.8 of ). The initial values to be assigned at the creation of the registry are as follows:

This document establishes a registry for QUIC tunnel control stream error codes. The "QUIC tunnel control Error Code" registry manages a 62-bit space. New values are assigned via IETF Review (Section 4.8 of ). The initial values to be assigned at the creation of the registry are as follows:

This document establishes a registry for QUIC tunnel Access Report Signal codes. The "QUIC tunnel Access Report Signal Code" registry manages a 62-bit space. New values are assigned via IETF Review (Section 4.8 of ). The initial values to be assigned at the creation of the registry are as follows:

In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. This document specifies a protocol for performing encapsulation of an arbitrary network layer protocol over another arbitrary network layer protocol. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. 3GPP (3rd Generation Partnership Project) RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. This document defines an extension to the QUIC transport protocol to add support for sending and receiving unreliable datagrams over a QUIC connection. Discussion of this work is encouraged to happen on the QUIC IETF mailing list quic@ietf.org [1] or on the GitHub repository which contains the draft: https://github.com/tfpauly/draft-pauly-quic- datagram [2]. This document describes MASQUE (Multiplexed Application Substrate over QUIC Encryption). MASQUE is a framework that allows concurrently running multiple networking applications inside an HTTP/3 connection. For example, MASQUE can allow a QUIC client to negotiate proxying capability with an HTTP/3 server, and subsequently make use of this functionality while concurrently processing HTTP/3 requests and responses. This document is a straw-man proposal. It does not contain enough details to implement the protocol, and is currently intended to spark discussions on the approach it is taking. Discussion of this work is encouraged to happen on the MASQUE IETF mailing list masque@ietf.org (mailto:masque@ietf.org) or on the GitHub repository which contains the draft: https://github.com/DavidSchinazi/masque-drafts (https://github.com/DavidSchinazi/masque-drafts). This document defines the core of the QUIC transport protocol. Accompanying documents describe QUIC's loss detection and congestion control and the use of TLS for key negotiation. Note to Readers Discussion of this draft takes place on the QUIC working group mailing list (quic@ietf.org (mailto:quic@ietf.org)), which is archived at https://mailarchive.ietf.org/arch/search/?email_list=quic Working Group information can be found at https://github.com/quicwg; source code and issues list for this draft can be found at https://github.com/quicwg/base-drafts/labels/-transport. This document describes how Transport Layer Security (TLS) is used to secure QUIC. Note to Readers Discussion of this draft takes place on the QUIC working group mailing list (quic@ietf.org (mailto:quic@ietf.org)), which is archived at https://mailarchive.ietf.org/arch/ search/?email_list=quic. Working Group information can be found at https://github.com/quicwg; source code and issues list for this draft can be found at https://github.com/quicwg/base-drafts/labels/-tls. This document specifies extensions to the QUIC protocol to enable the simultaneous usage of multiple paths for a single connection. The proposed extensions remain compliant with the current single-path QUIC design and preserve the QUIC privacy features. This memo defines and discusses requirements for devices that perform the network layer forwarding function of the Internet protocol suite. [STANDARDS-TRACK] This paper discusses a simple, effective, and straightforward method for using ingress traffic filtering to prohibit DoS (Denial of Service) attacks which use forged IP addresses to be propagated from 'behind' an Internet Service Provider's (ISP) aggregation point. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. The Port Control Protocol allows an IPv6 or IPv4 host to control how incoming IPv6 or IPv4 packets are translated and forwarded by a Network Address Translator (NAT) or simple firewall, and also allows a host to optimize its outgoing NAT keepalive messages. This document describes a Transport Layer Security (TLS) extension for application-layer protocol negotiation within the TLS handshake. For instances in which multiple application protocols are supported on the same TCP or UDP port, this extension allows the application layer to negotiate which protocol will be used within the TLS connection. Many protocols make use of points of extensibility that use constants to identify various protocol parameters. To ensure that the values in these fields do not have conflicting uses and to promote interoperability, their allocations are often coordinated by a central record keeper. For IETF protocols, that role is filled by the Internet Assigned Numbers Authority (IANA).To make assignments in a given registry prudently, guidance describing the conditions under which new values should be assigned, as well as when and how modifications to existing values can be made, is needed. This document defines a framework for the documentation of these guidelines by specification authors, in order to assure that the provided guidance for the IANA Considerations is clear and addresses the various issues that are likely in the operation of a registry.This is the third edition of this document; it obsoletes RFC 5226. TCP/IP communication is currently restricted to a single path per connection, yet multiple paths often exist between peers. The simultaneous use of these multiple paths for a TCP/IP session would improve resource usage within the network and, thus, improve user experience through higher throughput and improved resilience to network failure.Multipath TCP provides the ability to simultaneously use multiple paths between peers. This document presents a set of extensions to traditional TCP to support multipath operation. The protocol offers the same type of service to applications as TCP (i.e., reliable bytestream), and it provides the components necessary to establish and use multiple TCP flows across potentially disjoint paths. This document defines an Experimental Protocol for the Internet community. This document specifies a protocol for performing encapsulation of an arbitrary network layer protocol over another arbitrary network layer protocol. This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind.

Add the lightweight mode

Add the Access Report TLV for reporting access networks availability Add a section with examples of use of the Packet Tag

Separate the document in two and put the stream mode in another document Remove TCP Extended TLV Add a mechanism for joining QUIC connections in a QUIC tunneling session Add a format for encoding any network-layer protocol packets and Ethernet frames in QUIC DATAGRAM frames

Thanks to Quentin De Coninck and Francois Michel for their comments and the proofreading of the first version of this document. Thanks to Gregory Vander Schueren for his comments on the first version of this document.