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Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The abstract seems to contain references ([HTML5]), which it shouldn't. Please replace those with straight textual mentions of the documents in question. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == The document doesn't use any RFC 2119 keywords, yet has text resembling RFC 2119 boilerplate text. -- The document date (June 16, 2009) is 5428 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) -- Possible downref: Non-RFC (?) normative reference: ref. 'HTML5' ** Obsolete normative reference: RFC 2109 (Obsoleted by RFC 2965) ** Obsolete normative reference: RFC 2246 (Obsoleted by RFC 4346) ** Obsolete normative reference: RFC 2616 (Obsoleted by RFC 7230, RFC 7231, RFC 7232, RFC 7233, RFC 7234, RFC 7235) ** Obsolete normative reference: RFC 2965 (Obsoleted by RFC 6265) Summary: 6 errors (**), 0 flaws (~~), 2 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group I. Hickson 3 Internet-Draft Google, Inc. 4 Intended status: Standards Track June 16, 2009 5 Expires: December 18, 2009 7 The Web Socket protocol 8 draft-hixie-thewebsocketprotocol-17 10 Status of this Memo 12 This Internet-Draft is submitted to IETF in full conformance with the 13 provisions of BCP 78 and BCP 79. 15 Internet-Drafts are working documents of the Internet Engineering 16 Task Force (IETF), its areas, and its working groups. Note that 17 other groups may also distribute working documents as Internet- 18 Drafts. 20 Internet-Drafts are draft documents valid for a maximum of six months 21 and may be updated, replaced, or obsoleted by other documents at any 22 time. It is inappropriate to use Internet-Drafts as reference 23 material or to cite them other than as "work in progress." 25 The list of current Internet-Drafts can be accessed at 26 http://www.ietf.org/ietf/1id-abstracts.txt. 28 The list of Internet-Draft Shadow Directories can be accessed at 29 http://www.ietf.org/shadow.html. 31 This Internet-Draft will expire on December 18, 2009. 33 Copyright Notice 35 Copyright (c) 2009 IETF Trust and the persons identified as the 36 document authors. All rights reserved. 38 This document is subject to BCP 78 and the IETF Trust's Legal 39 Provisions Relating to IETF Documents in effect on the date of 40 publication of this document (http://trustee.ietf.org/license-info). 41 Please review these documents carefully, as they describe your rights 42 and restrictions with respect to this document. 44 Abstract 46 This protocol enables two-way communication between a user agent 47 running untrusted code running in a controlled environment to a 48 remote host that understands the protocol. It is intended to fail to 49 communicate with servers of pre-existing protocols like SMTP or HTTP, 50 while allowing HTTP servers to opt-in to supporting this protocol if 51 desired. It is designed to be easy to implement on the server side. 53 Author's note 55 This document is automatically generated from the same source 56 document as the HTML5 specification. [HTML5] 58 Table of Contents 60 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 61 2. Conformance requirements . . . . . . . . . . . . . . . . . . . 5 62 3. Client-side requirements . . . . . . . . . . . . . . . . . . . 6 63 3.1. Handshake . . . . . . . . . . . . . . . . . . . . . . . . 6 64 3.2. Data framing . . . . . . . . . . . . . . . . . . . . . . . 13 65 4. Server-side requirements . . . . . . . . . . . . . . . . . . . 15 66 4.1. Minimal handshake . . . . . . . . . . . . . . . . . . . . 15 67 4.2. Handshake details . . . . . . . . . . . . . . . . . . . . 16 68 4.3. Data framing . . . . . . . . . . . . . . . . . . . . . . . 17 69 5. Closing the connection . . . . . . . . . . . . . . . . . . . . 18 70 6. Security considerations . . . . . . . . . . . . . . . . . . . 19 71 7. IANA considerations . . . . . . . . . . . . . . . . . . . . . 20 72 8. Normative References . . . . . . . . . . . . . . . . . . . . . 21 73 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 22 75 1. Introduction 77 The WebSocket protocol is designed on the principle that there should 78 be minimal framing (the only framing that exists is to make the 79 protocol frame-based instead of stream-based, and to support a 80 distinction between Unicode text and binary frames). It is expected 81 that metadata would be layered on top of WebSocket by the application 82 layer, in the same way that metadata is layered on top of TCP/IP by 83 the application layer (HTTP). 85 Conceptually, WebSocket is really just a layer on top of TCP/IP that 86 adds a Web "origin"-based security model for browsers; adds an 87 addressing and protocol naming mechanism to support multiple services 88 on one port and multiple host names on one IP address; and layers a 89 framing mechanism on top of TCP to get back to the IP packet 90 mechanism that TCP is built on, but without length limits. Other 91 than that, it adds nothing. Basically it is intended to be as close 92 as possible to just exposing raw TCP/IP to script as possible given 93 the constraints of the Web. It's also designed in such a way that its 94 servers can share a port with HTTP servers, by having its handshake 95 be a valid HTTP Upgrade handshake also. 97 2. Conformance requirements 99 All diagrams, examples, and notes in this specification are non- 100 normative, as are all sections explicitly marked non-normative. 101 Everything else in this specification is normative. 103 The key words "MUST", "MUST NOT", "REQUIRED", "SHOULD", "SHOULD NOT", 104 "RECOMMENDED", "MAY", and "OPTIONAL" in the normative parts of this 105 document are to be interpreted as described in RFC2119. For 106 readability, these words do not appear in all uppercase letters in 107 this specification. [RFC2119] 109 Requirements phrased in the imperative as part of algorithms (such as 110 "strip any leading space characters" or "return false and abort these 111 steps") are to be interpreted with the meaning of the key word 112 ("must", "should", "may", etc) used in introducing the algorithm. 114 Conformance requirements phrased as algorithms or specific steps may 115 be implemented in any manner, so long as the end result is 116 equivalent. (In particular, the algorithms defined in this 117 specification are intended to be easy to follow, and not intended to 118 be performant.) 120 Implementations may impose implementation-specific limits on 121 otherwise unconstrained inputs, e.g. to prevent denial of service 122 attacks, to guard against running out of memory, or to work around 123 platform-specific limitations. 125 The conformance classes defined by this specification are user agents 126 and servers. 128 3. Client-side requirements 130 _This section only applies to user agents, not to servers._ 132 NOTE: This specification doesn't currently define a limit to the 133 number of simultaneous connections that a client can establish to a 134 server. 136 3.1. Handshake 138 When the user agent is to *establish a Web Socket connection* to a 139 host /host/, optionally on port /port/, from an origin /origin/, with 140 a flag /secure/, with a particular /resource name/, and optionally 141 with a particular /protocol/, it must run the following steps. 143 NOTE: The /host/ and /origin/ strings will be all-lowercase when this 144 algorithm is invoked. 146 1. If there is no explicit /port/, then: if /secure/ is false, let 147 /port/ be 81, otherwise let /port/ be 815. 149 2. If the user agent already has a Web Socket connection to the 150 remote host identified by /host/ (even if known by another 151 name), wait until that connection has been established or for 152 that connection to have failed. 154 NOTE: This makes it harder for a script to perform a denial of 155 service attack by just opening a large number of Web Socket 156 connections to a remote host. 158 NOTE: There is no limit to the number of established Web Socket 159 connections a user agent can have with a single remote host. 160 Servers can refuse to connect users with an excessive number of 161 connections, or disconnect resource-hogging users when suffering 162 high load. 164 3. If the user agent is configured to use a proxy to connect to 165 host /host/ and/or port /port/, then connect to that proxy and 166 ask it to open a TCP/IP connection to the host given by /host/ 167 and the port given by /port/. 169 EXAMPLE: For example, if the user agent uses an HTTP proxy 170 for all traffic, then if it was to try to connect to port 80 171 on server example.com, it might send the following lines to 172 the proxy server: 174 CONNECT example.com:80 HTTP/1.1 175 Host: example.com 177 If there was a password, the connection might look like: 179 CONNECT example.com:80 HTTP/1.1 180 Host: example.com 181 Proxy-authorization: Basic ZWRuYW1vZGU6bm9jYXBlcyE= 183 Otherwise, if the user agent is not configured to use a proxy, 184 then open a TCP/IP connection to the host given by /host/ and 185 the port given by /port/. 187 4. If the connection could not be opened, then fail the Web Socket 188 connection and abort these steps. 190 5. If /secure/ is true, perform a TLS handshake over the 191 connection. If this fails (e.g. the server's certificate could 192 not be verified), then fail the Web Socket connection and abort 193 these steps. Otherwise, all further communication on this 194 channel must run through the encrypted tunnel. [RFC2246] 196 6. Send the following bytes to the remote side (the server): 198 47 45 54 20 200 Send the /resource name/ value, encoded as US-ASCII. 202 Send the following bytes: 204 20 48 54 54 50 2f 31 2e 31 0d 0a 55 70 67 72 61 205 64 65 3a 20 57 65 62 53 6f 63 6b 65 74 0d 0a 43 206 6f 6e 6e 65 63 74 69 6f 6e 3a 20 55 70 67 72 61 207 64 65 0d 0a 209 NOTE: The string "GET ", the path, " HTTP/1.1", CRLF, the string 210 "Upgrade: WebSocket", CRLF, and the string "Connection: 211 Upgrade", CRLF. 213 7. Send the following bytes: 215 48 6f 73 74 3a 20 217 Send the /host/ value, encoded as US-ASCII. 219 Send the following bytes: 221 0d 0a 223 NOTE: The string "Host: ", the host, and CRLF. 225 8. Send the following bytes: 227 4f 72 69 67 69 6e 3a 20 229 Send the /origin/ value, encoded as US-ASCII. 231 NOTE: The /origin/ value is a string that was passed to this 232 algorithm. 234 Send the following bytes: 236 0d 0a 238 NOTE: The string "Origin: ", the origin, and CRLF. 240 9. If there is no /protocol/, then skip this step. 242 Otherwise, send the following bytes: 244 57 65 62 53 6f 63 6b 65 74 2d 50 72 6f 74 6f 63 245 6f 6c 3a 20 247 Send the /protocol/ value, encoded as US-ASCII. 249 Send the following bytes: 251 0d 0a 253 NOTE: The string "WebSocket-Protocol: ", the protocol, and CRLF. 255 10. If the client has any authentication information or cookies that 256 would be relevant to a resource accessed over HTTP, if /secure/ 257 is false, or HTTPS, if it is true, on host /host/, port /port/, 258 with /resource name/ as the path (and possibly query 259 parameters), then HTTP headers that would be appropriate for 260 that information should be sent at this point. [RFC2616] 261 [RFC2109] [RFC2965] 263 Each header must be on a line of its own (each ending with a CR 264 LF sequence). For the purposes of this step, each header must 265 not be split into multiple lines (despite HTTP otherwise 266 allowing this with continuation lines). 268 EXAMPLE: For example, if the server had a username and 269 password that applied to |http://example.com/socket|, and the 270 Web Socket was being opened to |ws://example.com:80/socket|, 271 it could send them: 273 Authorization: Basic d2FsbGU6ZXZl 275 However, it would not send them if the Web Socket was being 276 opened to |ws://example.com/socket|, as that uses a different 277 port (81, not 80). 279 11. Send the following bytes: 281 0d 0a 283 NOTE: Just a CRLF (a blank line). 285 12. Read the first 85 bytes from the server. If the connection 286 closes before 85 bytes are received, or if the first 85 bytes 287 aren't exactly equal to the following bytes, then fail the Web 288 Socket connection and abort these steps. 290 48 54 54 50 2f 31 2e 31 20 31 30 31 20 57 65 62 291 20 53 6f 63 6b 65 74 20 50 72 6f 74 6f 63 6f 6c 292 20 48 61 6e 64 73 68 61 6b 65 0d 0a 55 70 67 72 293 61 64 65 3a 20 57 65 62 53 6f 63 6b 65 74 0d 0a 294 43 6f 6e 6e 65 63 74 69 6f 6e 3a 20 55 70 67 72 295 61 64 65 0d 0a 297 NOTE: The string "HTTP/1.1 101 Web Socket Protocol Handshake", 298 CRLF, the string "Upgrade: WebSocket", CRLF, the string 299 "Connection: Upgrade", CRLF. 301 13. Let /headers/ be a list of name-value pairs, initially empty. 303 14. _Header_: Let /name/ and /value/ be empty byte arrays. 305 15. Read a byte from the server. 307 If the connection closes before this byte is received, then fail 308 the Web Socket connection and abort these steps. 310 Otherwise, handle the byte as described in the appropriate entry 311 below: 313 -> If the byte is 0x0d (ASCII CR) 314 If the /name/ byte array is empty, then jump to the headers 315 processing step. Otherwise, fail the Web Socket connection 316 and abort these steps. 318 -> If the byte is 0x0a (ASCII LF) 319 Fail the Web Socket connection and abort these steps. 321 -> If the byte is 0x3a (ASCII ":") 322 Move on to the next step. 324 -> If the byte is in the range 0x41 .. 0x5a (ASCII "A" .. "Z") 325 Append a byte whose value is the byte's value plus 0x20 to 326 the /name/ byte array and redo this step for the next byte. 328 -> Otherwise 329 Append the byte to the /name/ byte array and redo this step 330 for the next byte. 332 NOTE: This reads a header name, terminated by a colon, 333 converting upper-case ASCII letters to lowercase, and aborting 334 if a stray CR or LF is found. 336 16. Read a byte from the server. 338 If the connection closes before this byte is received, then fail 339 the Web Socket connection and abort these steps. 341 Otherwise, handle the byte as described in the appropriate entry 342 below: 344 -> If the byte is 0x20 (ASCII space) 345 Ignore the byte and move on to the next step. 347 -> Otherwise 348 Treat the byte as described by the list in the next step, 349 then move on to that next step for real. 351 NOTE: This skips past a space character after the colon, if 352 necessary. 354 17. Read a byte from the server. 356 If the connection closes before this byte is received, then fail 357 the Web Socket connection and abort these steps. 359 Otherwise, handle the byte as described in the appropriate entry 360 below: 362 -> If the byte is 0x0d (ASCII CR) 363 Move on to the next step. 365 -> If the byte is 0x0a (ASCII LF) 366 Fail the Web Socket connection and abort these steps. 368 -> Otherwise 369 Append the byte to the /name/ byte array and redo this step 370 for the next byte. 372 NOTE: This reads a header value, terminated by a CRLF. 374 18. Read a byte from the server. 376 If the connection closes before this byte is received, or if the 377 byte is not a 0x0a byte (ASCII LF), then fail the Web Socket 378 connection and abort these steps. 380 NOTE: This skips past the LF byte of the CRLF after the header. 382 19. Append an entry to the /headers/ list that has the name given by 383 the string obtained by interpreting the /name/ byte array as a 384 UTF-8 byte stream and the value given by the string obtained by 385 interpreting the /value/ byte array as a UTF-8 byte stream. 387 20. Return to the "Header" step above. 389 21. _Headers processing_: If there is not exactly one entry in the 390 /headers/ list whose name is "websocket-origin", or if there is 391 not exactly one entry in the /headers/ list whose name is 392 "websocket-location", or if the /protocol/ was specified but 393 there is not exactly one entry in the /headers/ list whose name 394 is "websocket-protocol", or if there are any entries in the 395 /headers/ list whose names are the empty string, then fail the 396 Web Socket connection and abort these steps. 398 22. Read a byte from the server. 400 If the connection closes before this byte is received, or if the 401 byte is not a 0x0a byte (ASCII LF), then fail the Web Socket 402 connection and abort these steps. 404 NOTE: This skips past the LF byte of the CRLF after the blank 405 line after the headers. 407 23. Handle each entry in the /headers/ list as follows: 409 -> If the entry's name is "websocket-origin|" 410 If the value is not exactly equal to /origin/, converted to 411 ASCII lowercase, then fail the Web Socket connection and 412 abort these steps. 414 -> If the entry's name is "websocket-location|" 415 If the value is not exactly equal to a string consisting of 416 the following components in the same order, then fail the Web 417 Socket connection and abort these steps: 419 1. The string "ws" if /secure/ is false and "wss" if 420 /secure/ is true 422 2. The three characters "://". 424 3. The value of /host/. 426 4. If /secure/ is false and /port/ is not 81, or if /secure/ 427 is true and /port/ is not 815: a ":" character followed 428 by the value of /port/. 430 5. The value of /resource name/. 432 -> If the entry's name is "websocket-protocol|" 433 If there was a /protocol/ specified, and the value is not 434 exactly equal to /protocol/, then fail the Web Socket 435 connection and abort these steps. (If no /protocol/ was 436 specified, the header is ignored.) 438 -> If the entry's name is "set-cookie|" or "set-cookie2|" or 439 another cookie-related header name 440 Handle the cookie as defined by the appropriate spec, with 441 the resource being the one with the host /host/, the port 442 /port/, the path (and possibly query parameters) /resource 443 name/, and the scheme |http| if /secure/ is false and |https| 444 if /secure/ is true. [RFC2109] [RFC2965] 446 -> Any other name 447 Ignore it. 449 24. The *Web Socket connection is established*. Now the user agent 450 must send and receive to and from the connection as described in 451 the next section. 453 To *fail the Web Socket connection*, the user agent must close the 454 Web Socket connection, and may report the problem to the user (which 455 would be especially useful for developers). However, user agents 456 must not convey the failure information to the script that attempted 457 the connection in a way distinguishable from the Web Socket being 458 closed normally. 460 3.2. Data framing 462 Once a Web Socket connection is established, the user agent must run 463 through the following state machine for the bytes sent by the server. 465 1. Try to read a byte from the server. Let /frame type/ be that 466 byte. 468 If no byte could be read because the Web Socket connection is 469 closed, then abort. 471 2. Handle the /frame type/ byte as follows: 473 If the high-order bit of the /frame type/ byte is set (i.e. if 474 /frame type/ _and_ed with 0x80 returns 0x80) 475 Run these steps. If at any point during these steps a read is 476 attempted but fails because the Web Socket connection is 477 closed, then abort. 479 1. Let /length/ be zero. 481 2. _Length_: Read a byte, let /b/ be that byte. 483 3. Let /b_v/ be integer corresponding to the low 7 bits of 484 /b/ (the value you would get by _and_ing /b/ with 0x7f). 486 4. Multiply /length/ by 128, add /b_v/ to that result, and 487 store the final result in /length/. 489 5. If the high-order bit of /b/ is set (i.e. if /b/ _and_ed 490 with 0x80 returns 0x80), then return to the step above 491 labeled _length_. 493 6. Read /length/ bytes. 495 7. Discard the read bytes. 497 If the high-order bit of the /frame type/ byte is _not_ set (i.e. 498 if /frame type/ _and_ed with 0x80 returns 0x00) 499 Run these steps. If at any point during these steps a read is 500 attempted but fails because the Web Socket connection is 501 closed, then abort. 503 1. Let /raw data/ be an empty byte array. 505 2. _Data_: Read a byte, let /b/ be that byte. 507 3. If /b/ is not 0xff, then append /b/ to /raw data/ and 508 return to the previous step (labeled _data_). 510 4. Interpret /raw data/ as a UTF-8 string, and store that 511 string in /data/. 513 5. If /frame type/ is 0x00, then *a message has been 514 received* with text /data/. Otherwise, discard the data. 516 3. Return to the first step to read the next byte. 518 If the user agent is faced with content that is too large to be 519 handled appropriately, then it must fail the Web Socket connection. 521 Once a Web Socket connection is established, the user agent must use 522 the following steps to *send /data/ using the Web Socket*: 524 1. Send a 0x00 byte to the server. 526 2. Encode /data/ using UTF-8 and send the resulting byte stream to 527 the server. 529 3. Send a 0xff byte to the server. 531 4. Server-side requirements 533 _This section only applies to servers._ 535 4.1. Minimal handshake 537 NOTE: This section describes the minimal requirements for a server- 538 side implementation of Web Sockets. 540 Listen on a port for TCP/IP. Upon receiving a connection request, 541 open a connection and send the following bytes back to the client: 543 48 54 54 50 2f 31 2e 31 20 31 30 31 20 57 65 62 544 20 53 6f 63 6b 65 74 20 50 72 6f 74 6f 63 6f 6c 545 20 48 61 6e 64 73 68 61 6b 65 0d 0a 55 70 67 72 546 61 64 65 3a 20 57 65 62 53 6f 63 6b 65 74 0d 0a 547 43 6f 6e 6e 65 63 74 69 6f 6e 3a 20 55 70 67 72 548 61 64 65 0d 0a 550 Send the string "WebSocket-Origin" followed by a U+003A COLON (":") 551 followed by the ASCII serialization of the origin from which the 552 server is willing to accept connections, followed by a CRLF pair 553 (0x0d 0x0a). 555 For instance: 557 WebSocket-Origin: http://example.com 559 Send the string "WebSocket-Location" followed by a U+003A COLON (":") 560 followed by the URL of the Web Socket script, followed by a CRLF pair 561 (0x0d 0x0a). 563 For instance: 565 WebSocket-Location: ws://example.com:80/demo 567 Send another CRLF pair (0x0d 0x0a). 569 Read data from the client until four bytes 0x0d 0x0a 0x0d 0x0a are 570 read. This data must either be discarded or handled as described in 571 the following section describing the handshake details. 573 If the connection isn't dropped at this point, go to the data framing 574 section. 576 4.2. Handshake details 578 The previous section ignores the data that is transmitted by the 579 client during the handshake. 581 The data sent by the client consists of a number of fields separated 582 by CR LF pairs (bytes 0x0d 0x0a). 584 The first field consists of three tokens separated by space 585 characters (byte 0x20). The middle token is the path being opened. 586 If the server supports multiple paths, then the server should echo 587 the value of this field in the initial handshake, as part of the URL 588 given on the |WebSocket-Location| line (after the appropriate scheme 589 and host). 591 If the first field does not have three tokens, the server should 592 abort the connection as it probably represents an errorneous client. 594 The remaining fields consist of name-value pairs, with the name part 595 separated from the value part by a colon and a space (bytes 0x3a 596 0x20). Of these, several are interesting: 598 Host (bytes 48 6f 73 74) 599 The value gives the hostname that the client intended to use when 600 opening the Web Socket. It would be of interest in particular to 601 virtual hosting environments, where one server might serve 602 multiple hosts, and might therefore want to return different data. 604 The right host has to be output as part of the URL given on the 605 |WebSocket-Location| line of the handshake described above, to 606 verify that the server knows that it is really representing that 607 host. 609 Origin (bytes 4f 72 69 67 69 6e) 610 The value gives the scheme, hostname, and port (if it's not the 611 default port for the given scheme) of the page that asked the 612 client to open the Web Socket. It would be interesting if the 613 server's operator had deals with operators of other sites, since 614 the server could then decide how to respond (or indeed, _whether_ 615 to respond) based on which site was requesting a connection. 617 If the server supports connections from more than one origin, then 618 the server should echo the value of this field in the initial 619 handshake, on the |WebSocket-Origin| line. 621 Other fields 622 Other fields can be used, such as "Cookie" or "Authorization", for 623 authentication purposes. 625 Any fields that lack the colon-space separator should be discarded 626 and may cause the server to disconnect. 628 4.3. Data framing 630 NOTE: This section only describes how to handle content that this 631 specification allows user agents to send (text). It doesn't handle 632 any arbitrary content in the same way that the requirements on user 633 agents defined earlier handle any content including possible future 634 extensions to the protocols. 636 The server must run through the following steps to process the bytes 637 sent by the client: 639 1. Read a byte from the client. Assuming everything is going 640 according to plan, it will be a 0x00 byte. If the byte is not a 641 0x00 byte, then the server may disconnect. 643 2. Let /raw data/ be an empty byte array. 645 3. _Data_: Read a byte, let /b/ be that byte. 647 4. If /b/ is not 0xff, then append /b/ to /raw data/ and return to 648 the previous step (labeled _data_). 650 5. Interpret /raw data/ as a UTF-8 string, and apply whatever 651 server-specific processing is to occur for the resulting string. 653 6. Return to the first step to read the next byte. 655 The server must run through the following steps to send strings to 656 the client: 658 1. Send a 0x00 byte to the client to indicate the start of a string. 660 2. Encode /data/ using UTF-8 and send the resulting byte stream to 661 the client. 663 3. Send a 0xff byte to the client to indicate the end of the 664 message. 666 5. Closing the connection 668 To *close the Web Socket connection*, either the user agent or the 669 server closes the TCP/IP connection. There is no closing handshake. 670 Whether the user agent or the server closes the connection, it is 671 said that the *Web Socket connection is closed*. 673 Servers may close the Web Socket connection whenever desired. 675 User agents should not close the Web Socket connection arbitrarily. 677 6. Security considerations 679 ** ISSUE ** ... 681 7. IANA considerations 683 ** ISSUE ** ...(two URI schemes, two ports, HTTP Upgrade keyword) 685 8. Normative References 687 [HTML5] Hickson, I., "HTML5", June 2009. 689 [RFC2109] Kristol, D. and L. Montulli, "HTTP State Management 690 Mechanism", RFC 2109, February 1997. 692 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 693 Requirement Levels", BCP 14, RFC 2119, March 1997. 695 [RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", 696 RFC 2246, January 1999. 698 [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., 699 Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext 700 Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. 702 [RFC2965] Kristol, D. and L. Montulli, "HTTP State Management 703 Mechanism", RFC 2965, October 2000. 705 Author's Address 707 Ian Hickson 708 Google, Inc. 710 Email: ian@hixie.ch 711 URI: http://ln.hixie.ch/