handshake

lib/web/fetch/data-url.js

@@ -737,6 +737,7 @@ module.exports = {
   collectAnHTTPQuotedString,
   serializeAMimeType,
   removeChars,
+  removeHTTPWhitespace,
   minimizeSupportedMimeType,
   HTTP_TOKEN_CODEPOINTS,
   isomorphicDecode

lib/web/websocket/connection.js

@@ -8,7 +8,7 @@ const {
   kReceivedClose,
   kResponse
 } = require('./symbols')
-const { fireEvent, failWebsocketConnection, isClosing, isClosed, isEstablished } = require('./util')
+const { fireEvent, failWebsocketConnection, isClosing, isClosed, isEstablished, parseExtensions } = require('./util')
 const { channels } = require('../../core/diagnostics')
 const { CloseEvent } = require('./events')
 const { makeRequest } = require('../fetch/request')
@@ -32,7 +32,7 @@ try {
  * @param {URL} url
  * @param {string|string[]} protocols
  * @param {import('./websocket').WebSocket} ws
- * @param {(response: any) => void} onEstablish
+ * @param {(response: any, extensions: string[] | undefined) => void} onEstablish
  * @param {Partial<import('../../types/websocket').WebSocketInit>} options
  */
 function establishWebSocketConnection (url, protocols, client, ws, onEstablish, options) {
@@ -93,11 +93,11 @@ function establishWebSocketConnection (url, protocols, client, ws, onEstablish,
   //    "permessage-deflate" extension header value.
   // https://github.com/mozilla/gecko-dev/blob/ce78234f5e653a5d3916813ff990f053510227bc/netwerk/protocol/websocket/WebSocketChannel.cpp#L2673
   // TODO: enable once permessage-deflate is supported
-  const permessageDeflate = '' // 'permessage-deflate; 15'
+  const permessageDeflate = 'permessage-deflate' // 'permessage-deflate; 15'
 
   // 10. Append (`Sec-WebSocket-Extensions`, permessageDeflate) to
   //     request’s header list.
-  // request.headersList.append('sec-websocket-extensions', permessageDeflate)
+  request.headersList.set('sec-websocket-extensions', permessageDeflate)
 
   // 11. Fetch request with useParallelQueue set to true, and
   //     processResponse given response being these steps:
@@ -168,10 +168,15 @@ function establishWebSocketConnection (url, protocols, client, ws, onEstablish,
       //    header field to determine which extensions are requested is
       //    discussed in Section 9.1.)
       const secExtension = response.headersList.get('Sec-WebSocket-Extensions')
+      let extensions
 
-      if (secExtension !== null && secExtension !== permessageDeflate) {
-        failWebsocketConnection(ws, 'Received different permessage-deflate than the one set.')
-        return
+      if (secExtension !== null) {
+        extensions = parseExtensions(secExtension)
+
+        if (!extensions.has(permessageDeflate)) {
+          failWebsocketConnection(ws, 'Sec-WebSocket-Extensions header does not match.')
+          return
+        }
       }
 
       // 6. If the response includes a |Sec-WebSocket-Protocol| header field
@@ -207,7 +212,7 @@ function establishWebSocketConnection (url, protocols, client, ws, onEstablish,
         })
       }
 
-      onEstablish(response)
+      onEstablish(response, extensions)
     }
   })
 

lib/web/websocket/receiver.js

@@ -33,10 +33,14 @@ class ByteParser extends Writable {
   #info = {}
   #fragments = []
 
-  constructor (ws) {
+  /** @type {Set<string>} */
+  #extensions
+
+  constructor (ws, extensions) {
     super()
 
     this.ws = ws
+    this.#extensions = new Set(extensions)
   }
 
   /**
@@ -91,7 +95,16 @@ class ByteParser extends Writable {
         // the negotiated extensions defines the meaning of such a nonzero
         // value, the receiving endpoint MUST _Fail the WebSocket
         // Connection_.
-        if (rsv1 !== 0 || rsv2 !== 0 || rsv3 !== 0) {
+        // This document allocates the RSV1 bit of the WebSocket header for
+        // PMCEs and calls the bit the "Per-Message Compressed" bit.  On a
+        // WebSocket connection where a PMCE is in use, this bit indicates
+        // whether a message is compressed or not.
+        if (rsv1 !== 0 && !this.#extensions.has('permessage-deflate')) {
+          failWebsocketConnection(this.ws, 'Expected RSV1 to be clear.')
+          return
+        }
+
+        if (rsv2 !== 0 || rsv3 !== 0) {
           failWebsocketConnection(this.ws, 'RSV1, RSV2, RSV3 must be clear')
           return
         }

lib/web/websocket/util.js

@@ -4,6 +4,7 @@ const { kReadyState, kController, kResponse, kBinaryType, kWebSocketURL } = requ
 const { states, opcodes } = require('./constants')
 const { ErrorEvent, createFastMessageEvent } = require('./events')
 const { isUtf8 } = require('node:buffer')
+const { collectASequenceOfCodePointsFast, removeHTTPWhitespace } = require('../fetch/data-url')
 
 /* globals Blob */
 
@@ -234,6 +235,30 @@ function isValidOpcode (opcode) {
   return isTextBinaryFrame(opcode) || isContinuationFrame(opcode) || isControlFrame(opcode)
 }
 
+/**
+ * Parses a Sec-WebSocket-Extensions header value.
+ * @param {string} extensions
+ * @returns {Map<string, string>}
+ */
+function parseExtensions (extensions) {
+  const position = { position: 0 }
+  const extensionList = new Map()
+
+  while (position.position < extensions.length) {
+    const pair = collectASequenceOfCodePointsFast(';', extensions, position)
+    const [name, value = ''] = pair.split('=')
+
+    extensionList.set(
+      removeHTTPWhitespace(name, true, false),
+      removeHTTPWhitespace(value, false, true)
+    )
+
+    position.position++
+  }
+
+  return extensionList
+}
+
 // https://nodejs.org/api/intl.html#detecting-internationalization-support
 const hasIntl = typeof process.versions.icu === 'string'
 const fatalDecoder = hasIntl ? new TextDecoder('utf-8', { fatal: true }) : undefined
@@ -265,5 +290,6 @@ module.exports = {
   isControlFrame,
   isContinuationFrame,
   isTextBinaryFrame,
-  isValidOpcode
+  isValidOpcode,
+  parseExtensions
 }

lib/web/websocket/websocket.js

@@ -135,7 +135,7 @@ class WebSocket extends EventTarget {
       protocols,
       client,
       this,
-      (response) => this.#onConnectionEstablished(response),
+      (response, extensions) => this.#onConnectionEstablished(response, extensions),
       options
     )
 
@@ -458,12 +458,12 @@ class WebSocket extends EventTarget {
   /**
    * @see https://websockets.spec.whatwg.org/#feedback-from-the-protocol
    */
-  #onConnectionEstablished (response) {
+  #onConnectionEstablished (response, parsedExtensions) {
     // processResponse is called when the "response’s header list has been received and initialized."
     // once this happens, the connection is open
     this[kResponse] = response
 
-    const parser = new ByteParser(this)
+    const parser = new ByteParser(this, parsedExtensions)
     parser.on('drain', onParserDrain)
     parser.on('error', onParserError.bind(this))