< draft-ietf-httpbis-h2-websockets-01.txt   draft-ietf-httpbis-h2-websockets-02.txt >
HTTP P. McManus HTTP P. McManus
Internet-Draft Mozilla Internet-Draft Mozilla
Intended status: Standards Track March 27, 2018 Updates: 6455 (if approved) May 2, 2018
Expires: September 28, 2018 Intended status: Standards Track
Expires: November 3, 2018
Bootstrapping WebSockets with HTTP/2 Bootstrapping WebSockets with HTTP/2
draft-ietf-httpbis-h2-websockets-01 draft-ietf-httpbis-h2-websockets-02
Abstract Abstract
This document defines a mechanism for running the WebSocket Protocol This document defines a mechanism for running the WebSocket Protocol
over a single stream of an HTTP/2 connection. over a single stream of an HTTP/2 connection.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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."
This Internet-Draft will expire on September 28, 2018. This Internet-Draft will expire on November 3, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 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 Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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6. Design Considerations . . . . . . . . . . . . . . . . . . . . 5 6. Design Considerations . . . . . . . . . . . . . . . . . . . . 5
7. About Intermediaries . . . . . . . . . . . . . . . . . . . . 6 7. About Intermediaries . . . . . . . . . . . . . . . . . . . . 6
8. Security Considerations . . . . . . . . . . . . . . . . . . . 6 8. Security Considerations . . . . . . . . . . . . . . . . . . . 6
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
11. Normative References . . . . . . . . . . . . . . . . . . . . 7 11. Normative References . . . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction 1. Introduction
The Hypertext Transfer Protocol (HTTP) provides compatible resource The Hypertext Transfer Protocol (HTTP) provides compatible resource-
level semantics across different versions but it does not offer level semantics across different versions but it does not offer
compatibility at the connection management level. Other protocols, compatibility at the connection management level. Other protocols,
such as WebSockets, that rely on connection management details of such as WebSockets, that rely on connection management details of
HTTP must be updated for new versions of HTTP. HTTP must be updated for new versions of HTTP.
The WebSocket Protocol [RFC6455] uses the HTTP/1.1 [RFC7230] Upgrade The WebSocket Protocol [RFC6455] uses the HTTP/1.1 [RFC7230] Upgrade
mechanism to transition a TCP connection from HTTP into a WebSocket mechanism to transition a TCP connection from HTTP into a WebSocket
connection. A different approach must be taken with HTTP/2 connection. A different approach must be taken with HTTP/2
[RFC7540]. HTTP/2 does not allow connection wide header and status [RFC7540]. HTTP/2 does not allow connection-wide headers and status
codes such as the Upgrade and Connection request headers or the 101 codes such as the Upgrade and Connection request headers or the 101
response code due to its multiplexing nature. These are all required response code due to its multiplexing nature. These are all required
by the [RFC6455] opening handshake. by the [RFC6455] opening handshake.
Being able to bootstrap WebSockets from HTTP/2 allows one TCP Being able to bootstrap WebSockets from HTTP/2 allows one TCP
connection to be shared by both protocols and extends HTTP/2's more connection to be shared by both protocols and extends HTTP/2's more
efficient use of the network to WebSockets. efficient use of the network to WebSockets.
This document extends the HTTP/2 CONNECT method. The extension This document extends the HTTP/2 CONNECT method. The extension
allows the substitution of a new protocol name to connect to rather allows the substitution of a new protocol name to connect to rather
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(or any other protocol). The other streams on the connection may (or any other protocol). The other streams on the connection may
carry more extended CONNECT tunnels, traditional HTTP/2 data, or a carry more extended CONNECT tunnels, traditional HTTP/2 data, or a
mixture of both. mixture of both.
This tunneled stream will be multiplexed with other regular streams This tunneled stream will be multiplexed with other regular streams
on the connection and enjoys the normal priority, cancellation, and on the connection and enjoys the normal priority, cancellation, and
flow control features of HTTP/2. flow control features of HTTP/2.
Streams that successfully establish a WebSocket connection using a Streams that successfully establish a WebSocket connection using a
tunneled stream and the modifications to the opening handshake tunneled stream and the modifications to the opening handshake
defined in this document then use the traditional WebSocket Protocol defined in this document then use the traditional WebSocket Protocol,
treating the stream as if were the TCP connection in that treating the stream as if were the TCP connection in that
specification. specification.
2. Terminology 2. Terminology
In this document, the key words "MUST", "MUST NOT", "REQUIRED", In this document, the key words "MUST", "MUST NOT", "REQUIRED",
"SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
and "OPTIONAL" are to be interpreted as described in BCP 14, and "OPTIONAL" are to be interpreted as described in BCP 14,
[RFC2119]. [RFC2119].
3. The SETTINGS_ENABLE_CONNECT_PROTOCOL SETTINGS Parameter 3. The SETTINGS_ENABLE_CONNECT_PROTOCOL SETTINGS Parameter
This document adds a new SETTINGS Parameter to those defined by This document adds a new SETTINGS Parameter to those defined by
[RFC7540], Section 6.5.2. [RFC7540], Section 6.5.2.
The new parameter name is SETTINGS_ENABLE_CONNECT_PROTOCOL. The The new parameter name is SETTINGS_ENABLE_CONNECT_PROTOCOL. The
value of the parameter MUST be 0 or 1. value of the parameter MUST be 0 or 1.
Upon receipt of SETTINGS_ENABLE_CONNECT_PROTOCOL with a value of 1 a Upon receipt of SETTINGS_ENABLE_CONNECT_PROTOCOL with a value of 1, a
client MAY use the Extended CONNECT definition of this document when client MAY use the Extended CONNECT definition of this document when
creating new streams. Receipt of this parameter by a server does not creating new streams. Receipt of this parameter by a server does not
have any impact. have any impact.
A sender MUST NOT send a SETTINGS_ENABLE_CONNECT_PROTOCOL parameter A sender MUST NOT send a SETTINGS_ENABLE_CONNECT_PROTOCOL parameter
with the value of 0 after previously sending a value of 1. with the value of 0 after previously sending a value of 1.
The use of a SETTINGS Parameter to opt-in to an otherwise The use of a SETTINGS Parameter to opt-in to an otherwise
incompatible protocol change is a use of "Extending HTTP/2" defined incompatible protocol change is a use of "Extending HTTP/2" defined
by Section 5.5 of [RFC7540]. If a client were to use the provisions by Section 5.5 of [RFC7540]. If a client were to use the provisions
of the extended CONNECT method defined in this document without first of the extended CONNECT method defined in this document without first
receiving a SETTINGS_ENABLE_CONNECT_PROTOCOL parameter, a non- receiving a SETTINGS_ENABLE_CONNECT_PROTOCOL parameter, a non-
supporting peer would detect a malformed request and generate a supporting peer would detect a malformed request and generate a
stream error (Section 8.1.2.6 of [RFC7540]). stream error (Section 8.1.2.6 of [RFC7540]).
4. The Extended CONNECT Method 4. The Extended CONNECT Method
The CONNECT Method defined in Section 8.3 of [RFC7540] is modified in Usage of the CONNECT method in HTTP/2 is defined by Section 8.3 of
the following ways: [RFC7540]. This extension modifies the method in the following ways:
o A new pseudo-header :protocol MAY be included on request HEADERS o A new pseudo-header :protocol MAY be included on request HEADERS
indicating the desired protocol to be spoken on the tunnel created indicating the desired protocol to be spoken on the tunnel created
by CONNECT. The pseudo-header is single valued and contains a by CONNECT. The pseudo-header is single valued and contains a
value from the HTTP Upgrade Token Registry defined by [RFC7230]. value from the HTTP Upgrade Token Registry defined by [RFC7230].
o On requests bearing the :protocol pseudo-header, the :scheme and o On requests bearing the :protocol pseudo-header, the :scheme and
:path pseudo-header fields MUST be included. :path pseudo-header fields MUST be included.
o On requests bearing the :protocol pseudo-header, the :authority o On requests bearing the :protocol pseudo-header, the :authority
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indicated by the :authority. indicated by the :authority.
Upon receiving a CONNECT request bearing the :protocol pseudo-header Upon receiving a CONNECT request bearing the :protocol pseudo-header
the server establishes a tunnel to another service of the protocol the server establishes a tunnel to another service of the protocol
type indicated by the pseudo-header. This service may or may not be type indicated by the pseudo-header. This service may or may not be
co-located with the server. co-located with the server.
5. Using Extended CONNECT To Bootstrap The WebSocket Protocol 5. Using Extended CONNECT To Bootstrap The WebSocket Protocol
The pseudo-header :protocol MUST be included in the CONNECT request The pseudo-header :protocol MUST be included in the CONNECT request
and it MUST have a value of websocket to initiate a WebSocket and it MUST have a value of "websocket" to initiate a WebSocket
connection on an HTTP/2 stream. Other HTTP request and response connection on an HTTP/2 stream. Other HTTP request and response
headers, such as those for manipulating cookies, may be included in headers, such as those for manipulating cookies, may be included in
the HEADERS with the CONNECT :method as usual. This request replaces the HEADERS with the CONNECT method as usual. This request replaces
the GET based request in [RFC6455] and is used to process the the GET-based request in [RFC6455] and is used to process the
WebSockets opening handshake. WebSockets opening handshake.
The scheme of the Target URI [RFC7230] MUST be https for wss schemed The scheme of the Target URI [RFC7230] MUST be "https" for "wss"
WebSockets and http for ws schemed WebSockets. The websocket URI is schemed WebSockets and "http" for "ws" schemed WebSockets. The
still used for proxy autoconfiguration. websocket URI is still used for proxy autoconfiguration.
[RFC6455] requires the use of Connection and Upgrade headers that are [RFC6455] requires the use of Connection and Upgrade headers that are
not part of HTTP/2. They MUST not be included in the CONNECT request not part of HTTP/2. They MUST not be included in the CONNECT request
defined here. defined here.
[RFC6455] requires the use of a Host header which is also not part of [RFC6455] requires the use of a Host header which is also not part of
HTTP/2. The Host information is conveyed as part of the :authority HTTP/2. The Host information is conveyed as part of the :authority
pseudo-header which is required on every HTTP/2 transaction. pseudo-header which is required on every HTTP/2 transaction.
Implementations using this extended CONNECT to bootstrap WebSockets Implementations using this extended CONNECT to bootstrap WebSockets
do not do the processing of the [RFC6455] Sec-WebSocket-Key and Sec- do not do the processing of the [RFC6455] Sec-WebSocket-Key and Sec-
WebSocket-Accept headers as that functionality has been superseded by WebSocket-Accept headers as that functionality has been superseded by
the :protocol pseudo-header. the :protocol pseudo-header.
The Sec-WebSocket-Version, Origin [RFC6454], Sec-WebSocket-Protocol, The Sec-WebSocket-Version, Origin [RFC6454], Sec-WebSocket-Protocol,
and Sec-WebSocket-Extensions headers are used on the CONNECT request and Sec-WebSocket-Extensions headers are used on the CONNECT request
and response headers in the same way as defined in [RFC6455]. Note and response headers in the same way as defined in [RFC6455]. Note
that HTTP/1 header names were case insensitive and HTTP/2 requires that HTTP/1 header names were case-insensitive and HTTP/2 requires
they be encoded as lower case. they be encoded as lower case.
After successfully processing the opening handshake the peers should After successfully processing the opening handshake, the peers should
proceed with The WebSocket Protocol [RFC6455] using the HTTP/2 stream proceed with The WebSocket Protocol [RFC6455] using the HTTP/2 stream
from the CONNECT transaction as if it were the TCP connection from the CONNECT transaction as if it were the TCP connection
referred to in [RFC6455]. The state of the WebSocket connection at referred to in [RFC6455]. The state of the WebSocket connection at
this point is OPEN as defined by [RFC6455], Section 4.1. this point is OPEN as defined by [RFC6455], Section 4.1.
The HTTP/2 stream closure is also analagous to the TCP connection of
[RFC6455]. Orderly TCP level closures are represented as END_STREAM
([RFC7540] Section 6.1) flags and RST exceptions are represented with
the RST_STREAM ([RFC7540] Section 6.4) frame with the CANCEL
([RFC7540] Secion 7) error code.
5.1. Example 5.1. Example
[[ From Client ]] [[ From Server ]] [[ From Client ]] [[ From Server ]]
SETTINGS SETTINGS
SETTINGS_ENABLE_CONNECT_PROTOCOL = 1 SETTINGS_ENABLE_CONNECT_PROTOCOL = 1
HEADERS + END_HEADERS HEADERS + END_HEADERS
:method = CONNECT :method = CONNECT
:protocol = websocket :protocol = websocket
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6. Design Considerations 6. Design Considerations
A more native integration with HTTP/2 is certainly possible with A more native integration with HTTP/2 is certainly possible with
larger additions to HTTP/2. This design was selected to minimize the larger additions to HTTP/2. This design was selected to minimize the
solution complexity while still addressing the primary concern of solution complexity while still addressing the primary concern of
running HTTP/2 and WebSockets concurrently. running HTTP/2 and WebSockets concurrently.
7. About Intermediaries 7. About Intermediaries
This document does not change how WebSockets interacts with HTTP This document does not change how WebSockets interacts with HTTP
proxies. If a client wishing to speak WebSockets connects via HTTP/2 forward proxies. If a client wishing to speak WebSockets connects
to a HTTP proxy it should continue to use a traditional (i.e. not via HTTP/2 to an HTTP proxy it should continue to use a traditional
with a :protocol pseudo-header) CONNECT to tunnel through that proxy (i.e. not with a :protocol pseudo-header) CONNECT to tunnel through
to the WebSocket server via HTTP. that proxy to the WebSocket server via HTTP.
The resulting version of HTTP on that tunnel determines whether The resulting version of HTTP on that tunnel determines whether
WebSockets is initiated directly or via a modified CONNECT request WebSockets is initiated directly or via a modified CONNECT request
described in this document. described in this document.
8. Security Considerations 8. Security Considerations
[RFC6455] ensures that non WebSockets clients, especially [RFC6455] ensures that non-WebSockets clients, especially
XMLHttpRequest based clients, cannot make a WebSocket connection. XMLHttpRequest based clients, cannot make a WebSocket connection.
Its primary mechanism for doing that is the use of Sec- prefixed Its primary mechanism for doing that is the use of Sec- prefixed
request headers that cannot be created by XMLHttpRequest based request headers that cannot be created by XMLHttpRequest-based
clients. This specification addresses that concern in two ways: clients. This specification addresses that concern in two ways:
o The CONNECT method is prohibited from being used by XMLHttpRequest o The CONNECT method is prohibited from being used by XMLHttpRequest
o The use of a pseudo-header is something that is connection o The use of a pseudo-header is something that is connection
specific and HTTP/2 does not ever allow to be created outside of specific and HTTP/2 does not ever allow to be created outside of
the protocol stack. the protocol stack.
9. IANA Considerations 9. IANA Considerations
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