Google LLC

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Google LLC

1600 Amphitheatre Parkway Mountain View, California 94043 United States of America dallasmccall@google.com

Google LLC

1600 Amphitheatre Parkway Mountain View, California 94043 United States of America dschinazi.ietf@gmail.com

MASQUE Internet-Draft This document describes the CONNECT-IP HTTP method. CONNECT-IP is similar to CONNECT-UDP, but allows transmitting IP packets, without being limited to just TCP like CONNECT or UDP like CONNECT-UDP. Discussion Venues Discussion of this document takes place on the Multiplexed Application Substrate over QUIC Encryption Working Group mailing list (masque@ietf.org), which is archived at . Source for this draft and an issue tracker can be found at .

Introduction This document describes the CONNECT-IP HTTP method. CONNECT-IP is similar to CONNECT-UDP, but allows transmitting IP packets, without being limited to just TCP like CONNECT or UDP like CONNECT-UDP. CONNECT-IP allows endpoints to set up an IP tunnel between one another. This can be used to implement a consumer VPN, point-to-point, point-to-network, and network-to-network capabilities as described in .

Conventions and Definitions 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. In this document, we use the term "proxy" to refer to the HTTP server that responds to the CONNECT-IP request. If there are HTTP intermediaries (as defined in Section 2.3 of ) between the client and the proxy, those are referred to as "intermediaries" in this document.

The CONNECT-IP Method The CONNECT-IP method establishes a stream to an endpoint server that then permits the exchange of control data, such as IP address information, reachable IP ranges, and other relevant information for successfully transmitting IP datagrams between hosts. The request-target of a CONNECT-IP request is a URI which uses the "https" scheme and an immutable path of "/". When using HTTP/2 or later, CONNECT-IP requests use HTTP pseudo-headers with the following requirements:

• The ":method" pseudo-header field is set to "CONNECT-IP".
• The ":scheme" pseudo-header field is set to "https".
• The ":path" pseudo-header field is set to "/".
• The ":authority" pseudo-header field contains the host and port of the proxy. The target of a CONNECT-IP request is the server providing the CONNECT-IP featureset, not an individual endpoint with which a connection is desired.

A CONNECT-IP request that does not conform to these restrictions is malformed (see , Section 8.1.2.6). Any 2xx (Successful) response indicates that the proxy is willing to open an IP tunnel between it and the client. Any response other than a successful response indicates that the tunnel has not yet been formed. A proxy MUST NOT send any Transfer-Encoding or Content-Length header fields in a 2xx (Successful) response to CONNECT-IP. A client MUST treat a successful response to CONNECT-IP containing any Content-Length or Transfer-Encoding header fields as malformed. A payload within a CONNECT-IP request message has no defined semantics; a CONNECT-IP request with a non-empty payload is malformed. Note that the CONNECT-IP stream is used to convey control messages, but they are not semantically part of the request or response themselves. Responses to the CONNECT-IP method are not cacheable. The lifetime of the tunnel is tied to the CONNECT-IP stream. Closing the stream (via the FIN bit on a QUIC STREAM frame, or a QUIC RESET_STREAM frame) closes the associated tunnel.

Transmitting IP Packets using HTTP Datagrams When the HTTP connection supports HTTP/3 datagrams , IP packets can be sent using them. The HTTP/3 Datagram Payload contains a full IP packet, from the IP Version field until the last byte of the IP Payload.

Routes Endpoints have the ability to advertise and reject routes using the ROUTE_ADVERTISEMENT () and ROUTE_REJECTION () messages. Note that these messages are purely informational: receipt of a ROUTE_ADVERTISEMENT message does not require the recipient to start routing traffic to its peer. Additionally, if an endpoint receives a ROUTE_REJECTION for a given prefix that it had previously received a ROUTE_ADVERTISEMENT message for, then the two cancel out and the endpoint MUST remove its state from the ROUTE_ADVERTISEMENT message instead of installing new state for the ROUTE_REJECTION message. Conversely, the same is true of a ROUTE_ADVERTISEMENT that matches a previous ROUTE_REJECTION. Routes are handled via longest-prefix-first preference, meaning that if a given IP prefix is covered by multiple route advertisement and route rejections, the one with the longest prefix is used.

Stream Chunks The DATA stream tied to the bidirectional stream that the CONNECT-IP request was sent on is a sequence of CONNECT-IP Stream Chunks, which are defined as a sequence of type-length-value tuples using the following format (using the notation from the "Notational Conventions" section of ):

CONNECT-IP Stream Format

CONNECT-IP Stream Chunk Format

CONNECT-IP Stream Chunk Type:

A variable-length integer indicating the Type of the CONNECT-IP Stream Chunk. Endpoints that receive a chunk with an unknown CONNECT-IP Stream Chunk Type MUST silently skip over that chunk.

CONNECT-IP Stream Chunk Length:

The length of the CONNECT-IP Stream Chunk Value field following this field. Note that this field can have a value of zero.

CONNECT-IP Stream Chunk Value:

The payload of this chunk. Its semantics are determined by the value of the CONNECT-IP Stream Chunk Type field.

Messages

IP_PACKET Message The IP_PACKET message allows conveying IP Packets when HTTP/3 Datagrams are not available. This message uses a CONNECT-IP Stream Chunk Type of 0x00. Its value uses the following format:

IP_PACKET Message Format

IP Packet:

A full IP packet, from the IP Version field until the last byte of the IP Payload.

Note that this message MAY still be used even when HTTP/3 datagrams are available.

ADDRESS_ASSIGN Message The ADDRESS_ASSIGN message allows an endpoint to inform its peer that it has assigned an IP address to it. It allows assigning a prefix which can contain multiple addresses. This message uses a CONNECT-IP Stream Chunk Type of 0x01. Its value uses the following format:

ADDRESS_ASSIGN Message Format

IP Version:

IP Version of this address assignment. MUST be either 4 or 6.

IP Address:

Assigned IP address. If the IP Version field has value 4, the IP Address field SHALL have a length of 32 bits. If the IP Version field has value 6, the IP Address field SHALL have a length of 128 bits.

IP Prefix Length:

Length of the IP Prefix assigned, in bits. MUST be lesser or equal to the length of the IP Address field, in bits.

ADDRESS_REQUEST Message The ADDRESS_REQUEST message allows an endpoint to request assignment of an IP address from its peer. It allows the endpoint to optionally indicate a preference for which address it would get assigned. This message uses a CONNECT-IP Stream Chunk Type of 0x02. Its value uses the following format:

ADDRESS_REQUEST Message Format

IP Version:

IP Version of this address request. MUST be either 4 or 6.

IP Address:

Requested IP address. If the IP Version field has value 4, the IP Address field SHALL have a length of 32 bits. If the IP Version field has value 6, the IP Address field SHALL have a length of 128 bits.

IP Prefix Length:

Length of the IP Prefix requested, in bits. MUST be lesser or equal to the length of the IP Address field, in bits.

Upon receiving the ADDRESS_REQUEST message, an endpoint SHOULD assign an IP address to its peer, and then respond with an ADDRESS_ASSIGN message to inform the peer of the assignment.

ROUTE_ADVERTISEMENT Message The ROUTE_ADVERTISEMENT message allows an endpoint to communicate to its peer that it is willing to route traffic to a given prefix. This message uses a CONNECT-IP Stream Chunk Type of 0x03. Its value uses the following format:

ROUTE_ADVERTISEMENT Message Format

IP Version:

IP Version of this route advertisement. MUST be either 4 or 6.

IP Address:

IP address of the advertised route. If the IP Version field has value 4, the IP Address field SHALL have a length of 32 bits. If the IP Version field has value 6, the IP Address field SHALL have a length of 128 bits.

IP Prefix Length:

Length of the IP Prefix of the advertised route, in bits. MUST be lesser or equal to the length of the IP Address field, in bits.

Upon receiving the ROUTE_ADVERTISEMENT message, an endpoint MAY start routing IP packets in that prefix to its peer.

ROUTE_REJECTION Message The ROUTE_REJECTION message allows an endpoint to communicate to its peer that it is not willing to route traffic to a given prefix. This message uses a CONNECT-IP Stream Chunk Type of 0x04. Its value uses the following format:

ROUTE_REJECTION Message Format

IP Version:

IP Version of this route rejection. MUST be either 4 or 6.

IP Address:

IP address of the rejected route. If the IP Version field has value 4, the IP Address field SHALL have a length of 32 bits. If the IP Version field has value 6, the IP Address field SHALL have a length of 128 bits.

IP Prefix Length:

Length of the IP Prefix of the advertised route, in bits. MUST be lesser or equal to the length of the IP Address field, in bits.

Upon receiving the ROUTE_REJECTION message, an endpoint MUST stop routing IP packets in that prefix to its peer. Note that this message can be reordered with DATAGRAM frames, and therefore an endpoint that receives packets for routes it has rejected MUST NOT treat that as an error.

ROUTE_RESET Message The ROUTE_RESET message allows an endpoint to cancel any routes it had previously advertised or denied. This message uses a CONNECT-IP Stream Chunk Type of 0x05. Its value uses the following format:

ROUTE_RESET Message Format

Upon receiving the ROUTE_RESET message, an endpoint MUST stop routing IP packets to its peer. Note that this message can be reordered with DATAGRAM frames, and therefore an endpoint that receives packets for routes it has rejected MUST NOT treat that as an error. The main purpose of the ROUTE_RESET message is to allow endpoints to not have to remember the full list of routes they have shared with their peer. In practice, it is expected that ROUTE_RESET messages will be closely followed by ROUTE_ADVERTISEMENT messages that will refill the routing table that was just cleared.

SHUTDOWN Message The SHUTDOWN message allows an endpoint to communicate to its peer that it is about to close the CONNECT-IP stream, with a string explaining the reason for the shutdown. This message uses a CONNECT-IP Stream Chunk Type of 0x06. Its value uses the following format:

SHUTDOWN Message Format

Reason Phrase:

Additional diagnostic information for the shutdown. This SHOULD be a UTF-8 encoded string , though the frame does not carry information, such as language tags, that would aid comprehension by any entity other than the one that created the text.

Note that the SHUTDOWN message is informational, the tunnel is only closed when its corresponding CONNECT-IP stream is closed. Endpoints MAY close the tunnel with a reason phrase by sending the SHUTDOWN message with the FIN bit set on the underlying QUIC STREAM frame that carried it.

ATOMIC_START Message The ATOMIC_START message allows an endpoint to create an atomic set of messages. This message uses a CONNECT-IP Stream Chunk Type of 0x07. Its value uses the following format:

ATOMIC_START Message Format

Upon receiving an ATOMIC_START message, an endpoint MUST buffer all incoming known messages until it receives an ATOMIC_END message. Endpoints MUST NOT send two ATOMIC_START messages without an ATOMIC_END message between them. Endpoints MUST NOT buffer unknown messages. Endpoints MAY choose to immediately process IP_PACKET and SHUTDOWN messages instead of buffering them. Extensions that register new message types MAY specify that it is allowed to skip buffering for them. The purpose of this frame is to avoid timing issues where an endpoint installs a route before an important route rejection was received. Endpoints SHOULD group their initial configuration into an atomic block to allow their peer to mark the tunnel as operational once the whole block is parsed.

ATOMIC_END Message The ATOMIC_END message allows an endpoint to end an atomic set of messages. This message uses a CONNECT-IP Stream Chunk Type of 0x08. Its value uses the following format:

ATOMIC_END Message Format

Upon receiving an ATOMIC_END message, an endpoint MUST parse all previously buffered messages, in order of receipt. Endpoints MUST NOT send an ATOMIC_END message without a preceding ATOMIC_START message.

Extensibility Considerations CONNECT-IP can be extended via multiple mechanisms to increase functionality. There are two main ways to extend CONNECT-IP: HTTP headers and CONNECT-IP Stream Chunk Types. For example, an authentication extension could define an HTTP header that allows endpoints to send authentication credentials to their peer during the creation of the tunnel. Alternatively, one could specify an extension that defines a new CONNECT-IP Stream Chunk Type which allows exchanging DNS configuration between endpoints.

Security Considerations There are significant risks in allowing arbitrary clients to establish a tunnel to arbitrary servers, as that could allow bad actors to send traffic and have it attributed to the proxy. Proxies that support CONNECT-IP SHOULD restrict its use to authenticated users. The HTTP Authorization header MAY be used to authenticate clients. More complex authentication schemes are out of scope for this document but can be implemented using CONNECT-IP extensions.

IANA Considerations

HTTP Method This document will request IANA to register "CONNECT-IP" in the HTTP Method Registry (IETF review) maintained at <>.

Stream Chunk Type Registration This document will request IANA to create a "CONNECT-IP Stream Chunk Type" registry. This registry governs a 62-bit space, and follows the registration policy for QUIC registries as defined in . In addition to the fields required by the QUIC policy, registrations in this registry MUST include the following fields:

Type:

A short mnemonic for the type.

Description:

A brief description of the type semantics, which MAY be a summary if a specification reference is provided.

The initial contents of this registry are: Each value of the format 41 * N + 29 for integer values of N (that is, 29, 70, 111, ...) are reserved; these values MUST NOT be assigned by IANA and MUST NOT appear in the listing of assigned values.

References Normative References 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. 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. The Hypertext Transfer Protocol (HTTP) is a stateless application-level protocol for distributed, collaborative, hypertext information systems. This document provides an overview of HTTP architecture and its associated terminology, defines the "http" and "https" Uniform Resource Identifier (URI) schemes, defines the HTTP/1.1 message syntax and parsing requirements, and describes related security concerns for implementations. A Uniform Resource Identifier (URI) is a compact sequence of characters that identifies an abstract or physical resource. This specification defines the generic URI syntax and a process for resolving URI references that might be in relative form, along with guidelines and security considerations for the use of URIs on the Internet. The URI syntax defines a grammar that is a superset of all valid URIs, allowing an implementation to parse the common components of a URI reference without knowing the scheme-specific requirements of every possible identifier. This specification does not define a generative grammar for URIs; that task is performed by the individual specifications of each URI scheme. [STANDARDS-TRACK] This specification describes an optimized expression of the semantics of the Hypertext Transfer Protocol (HTTP), referred to as HTTP version 2 (HTTP/2). HTTP/2 enables a more efficient use of network resources and a reduced perception of latency by introducing header field compression and allowing multiple concurrent exchanges on the same connection. It also introduces unsolicited push of representations from servers to clients. This specification is an alternative to, but does not obsolete, the HTTP/1.1 message syntax. HTTP's existing semantics remain unchanged. Google LLC Cloudflare The QUIC DATAGRAM extension provides application protocols running over QUIC with a mechanism to send unreliable data while leveraging the security and congestion-control properties of QUIC. However, QUIC DATAGRAM frames do not provide a means to demultiplex application contexts. This document defines how to use QUIC DATAGRAM frames when the application protocol running over QUIC is HTTP/3 by adding an identifier at the start of the frame payload. This allows HTTP messages to convey related information using unreliable DATAGRAM frames, ensuring those frames are properly associated with an HTTP message. 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/ietf- wg-masque/draft-ietf-masque-h3-datagram. Fastly Mozilla This document defines the core of the QUIC transport protocol. QUIC provides applications with flow-controlled streams for structured communication, low-latency connection establishment, and network path migration. QUIC includes security measures that ensure confidentiality, integrity, and availability in a range of deployment circumstances. Accompanying documents describe the integration of TLS for key negotiation, loss detection, and an exemplary congestion control algorithm. DO NOT DEPLOY THIS VERSION OF QUIC DO NOT DEPLOY THIS VERSION OF QUIC UNTIL IT IS IN AN RFC. This version is still a work in progress. For trial deployments, please use earlier versions. 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. ISO/IEC 10646-1 defines a large character set called the Universal Character Set (UCS) which encompasses most of the world's writing systems. The originally proposed encodings of the UCS, however, were not compatible with many current applications and protocols, and this has led to the development of UTF-8, the object of this memo. UTF-8 has the characteristic of preserving the full US-ASCII range, providing compatibility with file systems, parsers and other software that rely on US-ASCII values but are transparent to other values. This memo obsoletes and replaces RFC 2279. Informative References Google LLC Google LLC Google LLC There is interest among MASQUE working group participants in designing a protocol that can proxy IP traffic over HTTP. This document describes the set of requirements for such a protocol. Discussion of this work is encouraged to happen on the MASQUE IETF mailing list masque@ietf.org or on the GitHub repository which contains the draft: https://github.com/ietf-wg-masque/draft-ietf- masque-ip-proxy-reqs. The Hypertext Transfer Protocol (HTTP) is a stateless application- level protocol for distributed, collaborative, hypermedia information systems. This document defines the HTTP Authentication framework.

Examples

Consumer VPN In this scenario, the client will typically receive a single IP address that the proxy has picked from a pool of addresses it maintains. The client will route all traffic through the tunnel. The exchange could look as follows: IP Version = 4 IP Address = 0.0.0.0 IP Prefix Length = 0 <-------- ADDRESS_ASSIGN IP Version = 4 IP Address = 192.0.2.42 IP Prefix Length = 32 <-------- ROUTE_ADVERTISEMENT IP Version = 4 IP Address = 0.0.0.0 IP Prefix Length = 0 ]]>

Acknowledgments The design of CONNECT-IP was inspired by discussions in the MASQUE working group around . The authors would like to thank participants in those discussions for their feedback.