http2: add RFC 8441 extended connect protocol support

PR-URL: #23284
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

Author: jasnell

doc/api/http2.md

@@ -2278,7 +2278,7 @@ not work.
 For incoming headers:
 * The `:status` header is converted to `number`.
 * Duplicates of `:status`, `:method`, `:authority`, `:scheme`, `:path`,
-`age`, `authorization`, `access-control-allow-credentials`,
+`:protocol`, `age`, `authorization`, `access-control-allow-credentials`,
 `access-control-max-age`, `access-control-request-method`, `content-encoding`,
 `content-language`, `content-length`, `content-location`, `content-md5`,
 `content-range`, `content-type`, `date`, `dnt`, `etag`, `expires`, `from`,
@@ -2335,6 +2335,10 @@ properties.
 * `maxHeaderListSize` {number} Specifies the maximum size (uncompressed octets)
   of header list that will be accepted. The minimum allowed value is 0. The
   maximum allowed value is 2<sup>32</sup>-1. **Default:** `65535`.
+* `enableConnectProtocol`{boolean} Specifies `true` if the "Extended Connect
+  Protocol" defined by [RFC 8441][] is to be enabled. This setting is only
+  meaningful if sent by the server. Once the `enableConnectProtocol` setting
+  has been enabled for a given `Http2Session`, it cannot be disabled.
 
 All additional properties on the settings object are ignored.
 
@@ -2501,6 +2505,36 @@ req.on('end', () => {
 req.end('Jane');
 ```
 
+### The Extended CONNECT Protocol
+
+[RFC 8441][] defines an "Extended CONNECT Protocol" extension to HTTP/2 that
+may be used to bootstrap the use of an `Http2Stream` using the `CONNECT`
+method as a tunnel for other communication protocols (such as WebSockets).
+
+The use of the Extended CONNECT Protocol is enabled by HTTP/2 servers by using
+the `enableConnectProtocol` setting:
+
+```js
+const http2 = require('http2');
+const settings = { enableConnectProtocol: true };
+const server = http2.createServer({ settings });
+```
+
+Once the client receives the `SETTINGS` frame from the server indicating that
+the extended CONNECT may be used, it may send `CONNECT` requests that use the
+`':protocol'`  HTTP/2 pseudo-header:
+
+```js
+const http2 = require('http2');
+const client = http2.connect('http://localhost:8080');
+client.on('remoteSettings', (settings) => {
+  if (settings.enableConnectProtocol) {
+    const req = client.request({ ':method': 'CONNECT', ':protocol': 'foo' });
+    // ...
+  }
+});
+```
+
 ## Compatibility API
 
 The Compatibility API has the goal of providing a similar developer experience
@@ -3361,6 +3395,7 @@ following additional properties:
 [Readable Stream]: stream.html#stream_class_stream_readable
 [RFC 7838]: https://tools.ietf.org/html/rfc7838
 [RFC 8336]: https://tools.ietf.org/html/rfc8336
+[RFC 8441]: https://tools.ietf.org/html/rfc8441
 [Using `options.selectPadding()`]: #http2_using_options_selectpadding
 [`'checkContinue'`]: #http2_event_checkcontinue
 [`'request'`]: #http2_event_request

lib/internal/http2/core.js

@@ -191,6 +191,7 @@ const {
   HTTP2_HEADER_DATE,
   HTTP2_HEADER_METHOD,
   HTTP2_HEADER_PATH,
+  HTTP2_HEADER_PROTOCOL,
   HTTP2_HEADER_SCHEME,
   HTTP2_HEADER_STATUS,
   HTTP2_HEADER_CONTENT_LENGTH,
@@ -1451,7 +1452,7 @@ class ClientHttp2Session extends Http2Session {
 
     const connect = headers[HTTP2_HEADER_METHOD] === HTTP2_METHOD_CONNECT;
 
-    if (!connect) {
+    if (!connect || headers[HTTP2_HEADER_PROTOCOL] !== undefined) {
       if (headers[HTTP2_HEADER_AUTHORITY] === undefined)
         headers[HTTP2_HEADER_AUTHORITY] = this[kAuthority];
       if (headers[HTTP2_HEADER_SCHEME] === undefined)

lib/internal/http2/util.js

@@ -20,6 +20,7 @@ const {
   HTTP2_HEADER_AUTHORITY,
   HTTP2_HEADER_SCHEME,
   HTTP2_HEADER_PATH,
+  HTTP2_HEADER_PROTOCOL,
   HTTP2_HEADER_ACCESS_CONTROL_ALLOW_CREDENTIALS,
   HTTP2_HEADER_ACCESS_CONTROL_MAX_AGE,
   HTTP2_HEADER_ACCESS_CONTROL_REQUEST_METHOD,
@@ -78,7 +79,8 @@ const kValidPseudoHeaders = new Set([
   HTTP2_HEADER_METHOD,
   HTTP2_HEADER_AUTHORITY,
   HTTP2_HEADER_SCHEME,
-  HTTP2_HEADER_PATH
+  HTTP2_HEADER_PATH,
+  HTTP2_HEADER_PROTOCOL
 ]);
 
 // This set contains headers that are permitted to have only a single
@@ -89,6 +91,7 @@ const kSingleValueHeaders = new Set([
   HTTP2_HEADER_AUTHORITY,
   HTTP2_HEADER_SCHEME,
   HTTP2_HEADER_PATH,
+  HTTP2_HEADER_PROTOCOL,
   HTTP2_HEADER_ACCESS_CONTROL_ALLOW_CREDENTIALS,
   HTTP2_HEADER_ACCESS_CONTROL_MAX_AGE,
   HTTP2_HEADER_ACCESS_CONTROL_REQUEST_METHOD,
@@ -155,7 +158,8 @@ const IDX_SETTINGS_INITIAL_WINDOW_SIZE = 2;
 const IDX_SETTINGS_MAX_FRAME_SIZE = 3;
 const IDX_SETTINGS_MAX_CONCURRENT_STREAMS = 4;
 const IDX_SETTINGS_MAX_HEADER_LIST_SIZE = 5;
-const IDX_SETTINGS_FLAGS = 6;
+const IDX_SETTINGS_ENABLE_CONNECT_PROTOCOL = 6;
+const IDX_SETTINGS_FLAGS = 7;
 
 const IDX_SESSION_STATE_EFFECTIVE_LOCAL_WINDOW_SIZE = 0;
 const IDX_SESSION_STATE_EFFECTIVE_RECV_DATA_LENGTH = 1;
@@ -277,6 +281,12 @@ function getDefaultSettings() {
       settingsBuffer[IDX_SETTINGS_MAX_HEADER_LIST_SIZE];
   }
 
+  if ((flags & (1 << IDX_SETTINGS_ENABLE_CONNECT_PROTOCOL)) ===
+      (1 << IDX_SETTINGS_ENABLE_CONNECT_PROTOCOL)) {
+    holder.enableConnectProtocol =
+      settingsBuffer[IDX_SETTINGS_ENABLE_CONNECT_PROTOCOL];
+  }
+
   return holder;
 }
 
@@ -294,7 +304,8 @@ function getSettings(session, remote) {
     initialWindowSize: settingsBuffer[IDX_SETTINGS_INITIAL_WINDOW_SIZE],
     maxFrameSize: settingsBuffer[IDX_SETTINGS_MAX_FRAME_SIZE],
     maxConcurrentStreams: settingsBuffer[IDX_SETTINGS_MAX_CONCURRENT_STREAMS],
-    maxHeaderListSize: settingsBuffer[IDX_SETTINGS_MAX_HEADER_LIST_SIZE]
+    maxHeaderListSize: settingsBuffer[IDX_SETTINGS_MAX_HEADER_LIST_SIZE],
+    enableConnectProtocol: settingsBuffer[IDX_SETTINGS_ENABLE_CONNECT_PROTOCOL]
   };
 }
 
@@ -329,6 +340,11 @@ function updateSettingsBuffer(settings) {
     flags |= (1 << IDX_SETTINGS_ENABLE_PUSH);
     settingsBuffer[IDX_SETTINGS_ENABLE_PUSH] = Number(settings.enablePush);
   }
+  if (typeof settings.enableConnectProtocol === 'boolean') {
+    flags |= (1 << IDX_SETTINGS_ENABLE_CONNECT_PROTOCOL);
+    settingsBuffer[IDX_SETTINGS_ENABLE_CONNECT_PROTOCOL] =
+      Number(settings.enableConnectProtocol);
+  }
 
   settingsBuffer[IDX_SETTINGS_FLAGS] = flags;
 }

src/node_http2.cc

@@ -219,6 +219,7 @@ void Http2Session::Http2Settings::Init() {
   GRABSETTING(INITIAL_WINDOW_SIZE, "initial window size");
   GRABSETTING(MAX_HEADER_LIST_SIZE, "max header list size");
   GRABSETTING(ENABLE_PUSH, "enable push");
+  GRABSETTING(ENABLE_CONNECT_PROTOCOL, "enable connect protocol");
 
 #undef GRABSETTING
 
@@ -287,6 +288,8 @@ void Http2Session::Http2Settings::Update(Environment* env,
       fn(**session, NGHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE);
   buffer[IDX_SETTINGS_ENABLE_PUSH] =
       fn(**session, NGHTTP2_SETTINGS_ENABLE_PUSH);
+  buffer[IDX_SETTINGS_ENABLE_CONNECT_PROTOCOL] =
+      fn(**session, NGHTTP2_SETTINGS_ENABLE_CONNECT_PROTOCOL);
 }
 
 // Initializes the shared TypedArray with the default settings values.
@@ -3091,6 +3094,7 @@ void Initialize(Local<Object> target,
   NODE_DEFINE_CONSTANT(constants, NGHTTP2_SETTINGS_INITIAL_WINDOW_SIZE);
   NODE_DEFINE_CONSTANT(constants, NGHTTP2_SETTINGS_MAX_FRAME_SIZE);
   NODE_DEFINE_CONSTANT(constants, NGHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE);
+  NODE_DEFINE_CONSTANT(constants, NGHTTP2_SETTINGS_ENABLE_CONNECT_PROTOCOL);
 
   NODE_DEFINE_CONSTANT(constants, PADDING_STRATEGY_NONE);
   NODE_DEFINE_CONSTANT(constants, PADDING_STRATEGY_ALIGNED);

src/node_http2.h

@@ -160,6 +160,7 @@ struct nghttp2_header : public MemoryRetainer {
   V(AUTHORITY, ":authority")                                                  \
   V(SCHEME, ":scheme")                                                        \
   V(PATH, ":path")                                                            \
+  V(PROTOCOL, ":protocol")                                                    \
   V(ACCEPT_CHARSET, "accept-charset")                                         \
   V(ACCEPT_ENCODING, "accept-encoding")                                       \
   V(ACCEPT_LANGUAGE, "accept-language")                                       \

src/node_http2_state.h

@@ -15,6 +15,7 @@ namespace http2 {
     IDX_SETTINGS_MAX_FRAME_SIZE,
     IDX_SETTINGS_MAX_CONCURRENT_STREAMS,
     IDX_SETTINGS_MAX_HEADER_LIST_SIZE,
+    IDX_SETTINGS_ENABLE_CONNECT_PROTOCOL,
     IDX_SETTINGS_COUNT
   };
 

test/parallel/test-http2-binding.js

@@ -97,6 +97,7 @@ const expectedHeaderNames = {
   HTTP2_HEADER_AUTHORITY: ':authority',
   HTTP2_HEADER_SCHEME: ':scheme',
   HTTP2_HEADER_PATH: ':path',
+  HTTP2_HEADER_PROTOCOL: ':protocol',
   HTTP2_HEADER_DATE: 'date',
   HTTP2_HEADER_ACCEPT_CHARSET: 'accept-charset',
   HTTP2_HEADER_ACCEPT_ENCODING: 'accept-encoding',
@@ -217,7 +218,8 @@ const expectedNGConstants = {
   NGHTTP2_SETTINGS_MAX_CONCURRENT_STREAMS: 3,
   NGHTTP2_SETTINGS_INITIAL_WINDOW_SIZE: 4,
   NGHTTP2_SETTINGS_MAX_FRAME_SIZE: 5,
-  NGHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE: 6
+  NGHTTP2_SETTINGS_MAX_HEADER_LIST_SIZE: 6,
+  NGHTTP2_SETTINGS_ENABLE_CONNECT_PROTOCOL: 8
 };
 
 const defaultSettings = {

test/parallel/test-http2-connect-method-extended-cant-turn-off.js

@@ -0,0 +1,30 @@
+'use strict';
+
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+const assert = require('assert');
+const http2 = require('http2');
+
+const settings = { enableConnectProtocol: true };
+const server = http2.createServer({ settings });
+server.on('stream', common.mustNotCall());
+server.on('session', common.mustCall((session) => {
+  // This will force the connection to close because once extended connect
+  // is on, it cannot be turned off. The server is behaving badly.
+  session.settings({ enableConnectProtocol: false });
+}));
+
+server.listen(0, common.mustCall(() => {
+  const client = http2.connect(`http://localhost:${server.address().port}`);
+  client.on('remoteSettings', common.mustCall((settings) => {
+    assert(settings.enableConnectProtocol);
+    const req = client.request({
+      ':method': 'CONNECT',
+      ':protocol': 'foo'
+    });
+    req.on('error', common.mustCall(() => {
+      server.close();
+    }));
+  }));
+}));

test/parallel/test-http2-connect-method-extended.js

@@ -0,0 +1,39 @@
+'use strict';
+
+const common = require('../common');
+if (!common.hasCrypto)
+  common.skip('missing crypto');
+const assert = require('assert');
+const http2 = require('http2');
+
+const settings = { enableConnectProtocol: true };
+const server = http2.createServer({ settings });
+server.on('stream', common.mustCall((stream, headers) => {
+  assert.strictEqual(headers[':method'], 'CONNECT');
+  assert.strictEqual(headers[':scheme'], 'http');
+  assert.strictEqual(headers[':protocol'], 'foo');
+  assert.strictEqual(headers[':authority'],
+                     `localhost:${server.address().port}`);
+  assert.strictEqual(headers[':path'], '/');
+  stream.respond();
+  stream.end('ok');
+}));
+
+server.listen(0, common.mustCall(() => {
+  const client = http2.connect(`http://localhost:${server.address().port}`);
+  client.on('remoteSettings', common.mustCall((settings) => {
+    assert(settings.enableConnectProtocol);
+    const req = client.request({
+      ':method': 'CONNECT',
+      ':protocol': 'foo'
+    });
+    req.resume();
+    req.on('end', common.mustCall());
+    req.on('close', common.mustCall(() => {
+      assert.strictEqual(req.rstCode, 0);
+      server.close();
+      client.close();
+    }));
+    req.end();
+  }));
+}));