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In particular the server MUST not make a new TCP connection to the host and port indicated by the :authority. == Using lowercase 'not' together with uppercase 'MUST', 'SHALL', 'SHOULD', or 'RECOMMENDED' is not an accepted usage according to RFC 2119. Please use uppercase 'NOT' together with RFC 2119 keywords (if that is what you mean). Found 'MUST not' in this paragraph: [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 defined here. -- The document date (November 11, 2017) is 2356 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 7230 (Obsoleted by RFC 9110, RFC 9112) ** Obsolete normative reference: RFC 7540 (Obsoleted by RFC 9113) Summary: 3 errors (**), 0 flaws (~~), 4 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group P. McManus 3 Internet-Draft Mozilla 4 Intended status: Standards Track November 11, 2017 5 Expires: May 15, 2018 7 Bootstrapping WebSockets with HTTP/2 8 draft-mcmanus-httpbis-h2-websockets-02 10 Abstract 12 This document defines a mechanism for running the WebSocket Protocol 13 [RFC6455] over a single stream of an HTTP/2 connection. 15 Status of This Memo 17 This Internet-Draft is submitted in full conformance with the 18 provisions of BCP 78 and BCP 79. 20 Internet-Drafts are working documents of the Internet Engineering 21 Task Force (IETF). Note that other groups may also distribute 22 working documents as Internet-Drafts. The list of current Internet- 23 Drafts is at https://datatracker.ietf.org/drafts/current/. 25 Internet-Drafts are draft documents valid for a maximum of six months 26 and may be updated, replaced, or obsoleted by other documents at any 27 time. It is inappropriate to use Internet-Drafts as reference 28 material or to cite them other than as "work in progress." 30 This Internet-Draft will expire on May 15, 2018. 32 Copyright Notice 34 Copyright (c) 2017 IETF Trust and the persons identified as the 35 document authors. All rights reserved. 37 This document is subject to BCP 78 and the IETF Trust's Legal 38 Provisions Relating to IETF Documents 39 (https://trustee.ietf.org/license-info) in effect on the date of 40 publication of this document. Please review these documents 41 carefully, as they describe your rights and restrictions with respect 42 to this document. Code Components extracted from this document must 43 include Simplified BSD License text as described in Section 4.e of 44 the Trust Legal Provisions and are provided without warranty as 45 described in the Simplified BSD License. 47 Table of Contents 49 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 50 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 51 3. The ENABLE_CONNECT_PROTOCOL SETTINGS Parameter . . . . . . . 3 52 4. The Extended CONNECT Method . . . . . . . . . . . . . . . . . 3 53 5. Using Extended CONNECT To Bootstrap The WebSocket Protocol . 4 54 5.1. Example . . . . . . . . . . . . . . . . . . . . . . . . . 5 55 6. Design Considerations . . . . . . . . . . . . . . . . . . . . 5 56 7. About Intermediaries . . . . . . . . . . . . . . . . . . . . 5 57 8. Security Considerations . . . . . . . . . . . . . . . . . . . 6 58 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 59 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 60 11. Normative References . . . . . . . . . . . . . . . . . . . . 6 61 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7 63 1. Introduction 65 The Hypertext Transfer Protocol (HTTP) provides compatible resource 66 level semantics across different versions but it does not offer 67 compatibility at the connection management level. Other protocols, 68 such as WebSockets, that rely on connection management details of 69 HTTP must be updated for new versions of HTTP. 71 The WebSocket Protocol [RFC6455] uses the HTTP/1.1 [RFC7230] Upgrade 72 mechanism to transition a TCP connection from HTTP into a WebSocket 73 connection. A different approach must be taken with HTTP/2 74 [RFC7540]. The multiplexing nature of HTTP/2 does not allow 75 connection wide header and status codes such as the Upgrade and 76 Connection request headers or the 101 response code due to its 77 multiplexing nature. These are all required by the [RFC6455] opening 78 handshake. 80 Being able to bootstrap WebSockets from HTTP/2 allows one TCP 81 connection to be shared by both protocols and extends HTTP/2's more 82 efficient use of the network to WebSockets. 84 This document extends the HTTP/2 CONNECT method. The extension 85 allows the substitution of a new protocol name to connect to rather 86 than the external host normally used by CONNECT. The result is a 87 tunnel on a single HTTP/2 stream that can carry data for WebSockets 88 (or any other protocol). The other streams on the connection may 89 carry more extended CONNECT tunnels, traditional HTTP/2 data, or a 90 mixture of both. 92 This tunneled stream will be multiplexed with other regular streams 93 on the connection and enjoys the normal priority, cancellation, and 94 flow control features of HTTP/2. 96 Streams that successfully establish a WebSocket connection using a 97 tunneled stream and the modifications to the opening handshake 98 defined in this document then use the traditional WebSocket Protocol 99 treating the stream as if were the TCP connection in that 100 specification. 102 2. Terminology 104 In this document, the key words "MUST", "MUST NOT", "REQUIRED", 105 "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", 106 and "OPTIONAL" are to be interpreted as described in BCP 14, 107 [RFC2119]. 109 3. The ENABLE_CONNECT_PROTOCOL SETTINGS Parameter 111 This document adds a new SETTINGS Parameter to those defined by 112 [RFC7540] Section 6.5.2. 114 The new parameter is ENABLE_CONNECT_PROTOCOL (type = 0x8). The value 115 of the parameter MUST be 0 or 1. 117 Upon receipt of ENABLE_CONNECT_PROTOCOL with a value of 1 a client 118 MAY use the Extended CONNECT definition of this document when 119 creating new streams. Receipt of this parameter by a server does not 120 have any impact. 122 A sender MUST NOT send a ENABLE_CONNECT_PROTOCOL parameter with the 123 value of 0 after previously sending a value of 1. 125 The use of a SETTINGS Parameter to opt-in to an otherwise 126 incompatible protocol change is a use of "Extending HTTP/2" defined 127 by section 5.5 of [RFC7540]. If a client were to use the provisions 128 of the extended CONNECT method defined in this document without first 129 receiving a ENABLE_CONNECT_PROTOCOL parameter with the value of 1 it 130 would be a protocol violation. 132 4. The Extended CONNECT Method 134 The CONNECT Method of [RFC7540] Section 8.3 is modified in the 135 following ways: 137 o A new pseudo-header :protocol MAY be included on request HEADERS 138 indicating the desired protocol to be spoken on the tunnel created 139 by CONNECT. The pseudo-header is single valued and contains a 140 value from the HTTP Upgrade Token Registry defined by [RFC7230]. 142 o On requests bearing the :protocol pseudo-header, the :scheme and 143 :path pseudo-header fields SHOULD be included. 145 o On requests bearing the :protocol pseudo-header, the :authority 146 pseudo-header field is interpreted according to [RFC7540] 147 Section 8.1.2.3 instead of [RFC7540] Section 8.3. In particular 148 the server MUST not make a new TCP connection to the host and port 149 indicated by the :authority. 151 Upon receiving a CONNECT request bearing the :protocol pseudo-header 152 the server establishes a tunnel to another service of the protocol 153 type indicated by the pseudo-header. This service may or may not be 154 co-located with the server. 156 5. Using Extended CONNECT To Bootstrap The WebSocket Protocol 158 The pseudo-header :protocol MUST be included in the CONNECT request 159 and it MUST have a value of websocket to initiate a WebSocket 160 connection on an HTTP/2 stream. Other HTTP request and response 161 headers, such as those for manipulating cookies, may be included in 162 the HEADERS with the CONNECT :method as usual. This request replaces 163 the GET based request in [RFC6455] and is used to process the 164 WebSockets opening handshake. 166 The scheme of the Target URI [RFC7230] MUST be https for wss schemed 167 WebSockets and http for ws schemed WebSockets. The websocket URI is 168 still used for proxy autoconfiguration. 170 [RFC6455] requires the use of Connection and Upgrade headers that are 171 not part of HTTP/2. They MUST not be included in the CONNECT request 172 defined here. 174 [RFC6455] requires the use of a Host header which is also not part of 175 HTTP/2. The Host information is conveyed as part of the :authority 176 pseudo-header which is required on every HTTP/2 transaction. 178 Implementations using this extended CONNECT to bootstrap WebSockets 179 do not do the processing of the [RFC6455] Sec-WebSocket-Key and Sec- 180 WebSocket-Accept headers as that functionality has been superceded by 181 the :protocol pseudo-header. 183 The Sec-WebSocket-Version, Origin [RFC6454], Sec-WebSocket-Protocol, 184 and Sec-WebSocket-Extensions headers are used on the CONNECT request 185 and response headers in the same way as defined in [RFC6455]. Note 186 that HTTP/1 header names were case insensitive and HTTP/2 requires 187 they be encoded as lower case. 189 After successfully processing the opening handshake the peers should 190 proceed with The WebSocket Protocol [RFC6455] using the HTTP/2 stream 191 from the CONNECT transaction as if it were the TCP connection 192 referred to in [RFC6455]. The state of the WebSocket connection at 193 this point is OPEN as defined by [RFC6455] Section 4.1. 195 5.1. Example 197 [[ From Client ]] [[ From Server ]] 199 SETTINGS 200 ENABLE_CONNECT_PROTOCOL = 1 202 HEADERS + END_HEADERS 203 :method = CONNECT 204 :protocol = websocket 205 :scheme = https 206 :path = /chat 207 :authority = server.example.com:443 208 sec-websocket-protocol = chat, superchat 209 sec-websocket-extensions = permessage-deflate 210 sec-websocket-version = 13 211 origin = http://www.example.com 213 HEADERS + END_HEADERS 214 :status = 200 215 sec-websocket-protocol = chat 217 DATA 218 WebSocket Data 220 DATA + END_STREAM 221 WebSocket Data 223 DATA + END_STREAM 224 WebSocket Data 226 6. Design Considerations 228 A more native integration with HTTP/2 is certainly possible with 229 larger additions to HTTP/2. This design was selected to minimize the 230 solution complexity while still addressing the primary concern of 231 running HTTP/2 and WebSockets concurrently. 233 7. About Intermediaries 235 This document does not change how WebSockets interacts with HTTP 236 proxies. If a client wishing to speak WebSockets connects via HTTP/2 237 to a HTTP proxy it should continue to use a traditional (i.e. not 238 with a :protocol pseudo-header) CONNECT to tunnel through that proxy 239 to the WebSocket server via HTTP. 241 The resulting version of HTTP on that tunnel determines whether 242 WebSockets is initiated directly or via a modified CONNECT request 243 described in this document. 245 8. Security Considerations 247 [RFC6455] ensures that non WebSockets clients, especially 248 XMLHttpRequest based clients, cannot make a WebSocket connection. 249 Its primary mechanism for doing that is the use of Sec- prefixed 250 request headers that cannot be created by XMLHttpRequest based 251 clients. This specification addresses that concern in two ways: 253 o The CONNECT method is prohibited from being used by XMLHttpRequest 255 o The use of a pseudo-header is something that is connection 256 specific and HTTP/2 does not ever allow to be created outside of 257 the protocol stack. 259 9. IANA Considerations 261 This document establishes a entry for the HTTP/2 Settings Registry 262 that was established by [RFC7540] Section 11.3 264 Name: ENABLE_CONNECT_PROTOCOL 266 Code: 0x8 268 Initial Value: 0 270 Specification: This document 272 10. Acknowledgments 274 The 2017 HTTP Workshop had a very productive discussion that helped 275 determine the key problem and acceptable level of solution 276 complexity. 278 11. Normative References 280 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 281 Requirement Levels", BCP 14, RFC 2119, 282 DOI 10.17487/RFC2119, March 1997, 283 . 285 [RFC6454] Barth, A., "The Web Origin Concept", RFC 6454, 286 DOI 10.17487/RFC6454, December 2011, 287 . 289 [RFC6455] Fette, I. and A. Melnikov, "The WebSocket Protocol", 290 RFC 6455, DOI 10.17487/RFC6455, December 2011, 291 . 293 [RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer 294 Protocol (HTTP/1.1): Message Syntax and Routing", 295 RFC 7230, DOI 10.17487/RFC7230, June 2014, 296 . 298 [RFC7540] Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext 299 Transfer Protocol Version 2 (HTTP/2)", RFC 7540, 300 DOI 10.17487/RFC7540, May 2015, 301 . 303 Author's Address 305 Patrick McManus 306 Mozilla 308 Email: mcmanus@ducksong.com