http2: receive customsettings

This commit gives node.js the ability to also receive custom settings,
in addition to sending, them which was implemented before.
The custom settings received are limited to setting ids,
that were specified before, when creating the session eithers through
the server or the client.

Author: martenrichter

doc/api/http2.md

@@ -2498,6 +2498,11 @@ changes:
     **Default:** `100`.
   * `settings` {HTTP/2 Settings Object} The initial settings to send to the
     remote peer upon connection.
+  * `remoteCustomSettings` {Array} The array of integer values determines the
+    settings types, which are included in the `CustomSettings`-property of
+    the received remoteSettings. Please see the `CustomSettings`-property of
+    the `Http2Settings` object for more information,
+    on the allowed setting types.
   * `Http1IncomingMessage` {http.IncomingMessage} Specifies the
     `IncomingMessage` class to used for HTTP/1 fallback. Useful for extending
     the original `http.IncomingMessage`. **Default:** `http.IncomingMessage`.
@@ -2652,6 +2657,10 @@ changes:
     **Default:** `100`.
   * `settings` {HTTP/2 Settings Object} The initial settings to send to the
     remote peer upon connection.
+  * `remoteCustomSettings` {Array} The array of integer values determines the
+    settings types, which are included in the `customSettings`-property of the
+    received remoteSettings. Please see the `customSettings`-property of the
+    `Http2Settings` object for more information, on the allowed setting types.
   * ...: Any [`tls.createServer()`][] options can be provided. For
     servers, the identity options (`pfx` or `key`/`cert`) are usually required.
   * `origins` {string\[]} An array of origin strings to send within an `ORIGIN`
@@ -2780,6 +2789,10 @@ changes:
     `'https:'`
   * `settings` {HTTP/2 Settings Object} The initial settings to send to the
     remote peer upon connection.
+  * `remoteCustomSettings` {Array} The array of integer values determines the
+    settings types, which are included in the `CustomSettings`-property of the
+    received remoteSettings. Please see the `CustomSettings`-property of the
+    `Http2Settings` object for more information, on the allowed setting types.
   * `createConnection` {Function} An optional callback that receives the `URL`
     instance passed to `connect` and the `options` object, and returns any
     [`Duplex`][] stream that is to be used as the connection for this session.
@@ -3022,9 +3035,11 @@ properties.
   it should be greater than 6, although it is not an error.
   The values need to be unsigned integers in the range from 0 to 2^32-1.
   Currently, a maximum of up 10 custom settings is supported.
-  It is only supported for sending SETTINGS.
-  Custom settings are not supported for the functions retrieving remote and
-  local settings as nghttp2 does not pass unknown HTTP/2 settings to Node.js.
+  It is only supported for sending SETTINGS, or for receiving settings values
+  specified in the `remoteCustomSettings` options of the server or client
+  object. Do not mix the `customSettings`-mechanism for a settings id with
+  interfaces for the natively handled settings, in case a setting becomes
+  natively supported in a future node version.
 
 All additional properties on the settings object are ignored.
 

lib/internal/http2/core.js

@@ -9,9 +9,11 @@ const {
   FunctionPrototypeBind,
   FunctionPrototypeCall,
   MathMin,
+  Number,
   ObjectAssign,
   ObjectKeys,
   ObjectDefineProperty,
+  ObjectEntries,
   ObjectPrototypeHasOwnProperty,
   Promise,
   PromisePrototypeThen,
@@ -105,6 +107,7 @@ const {
     ERR_HTTP2_STREAM_CANCEL,
     ERR_HTTP2_STREAM_ERROR,
     ERR_HTTP2_STREAM_SELF_DEPENDENCY,
+    ERR_HTTP2_TOO_MANY_CUSTOM_SETTINGS,
     ERR_HTTP2_TRAILERS_ALREADY_SENT,
     ERR_HTTP2_TRAILERS_NOT_READY,
     ERR_HTTP2_UNSUPPORTED_PROTOCOL,
@@ -140,6 +143,7 @@ const {
 
 const {
   assertIsObject,
+  assertIsArray,
   assertValidPseudoHeader,
   assertValidPseudoHeaderResponse,
   assertValidPseudoHeaderTrailer,
@@ -155,7 +159,9 @@ const {
   kRequest,
   kProxySocket,
   mapToHeaders,
+  MAX_ADDITIONAL_SETTINGS,
   NghttpError,
+  remoteCustomSettingsToBuffer,
   sessionName,
   toHeaderObject,
   updateOptionsBuffer,
@@ -947,6 +953,15 @@ function pingCallback(cb) {
 const validateSettings = hideStackFrames((settings) => {
   if (settings === undefined) return;
   assertIsObject.withoutStackTrace(settings.customSettings, 'customSettings', 'Number');
+  if (settings.customSettings) {
+    const entries = ObjectEntries(settings.customSettings);
+    if (entries.length > MAX_ADDITIONAL_SETTINGS)
+      throw new ERR_HTTP2_TOO_MANY_CUSTOM_SETTINGS();
+    for (const { 0: key, 1: value } of entries) {
+      assertWithinRange.withoutStackTrace('customSettings:id', Number(key), 0, 0xffff);
+      assertWithinRange.withoutStackTrace('customSettings:value', Number(value), 0, kMaxInt);
+    }
+  }
 
   assertWithinRange.withoutStackTrace('headerTableSize',
                                       settings.headerTableSize,
@@ -1031,6 +1046,9 @@ function setupHandle(socket, type, options) {
   this[kState].flags |= SESSION_FLAGS_READY;
 
   updateOptionsBuffer(options);
+  if (options.remoteCustomSettings) {
+    remoteCustomSettingsToBuffer(options.remoteCustomSettings);
+  }
   const handle = new binding.Http2Session(type);
   handle[kOwner] = this;
 
@@ -3103,6 +3121,13 @@ function initializeOptions(options) {
   assertIsObject(options.settings, 'options.settings');
   options.settings = { ...options.settings };
 
+  assertIsArray(options.remoteCustomSettings, 'options.remoteCustomSettings');
+  if (options.remoteCustomSettings) {
+    options.remoteCustomSettings = [ ...options.remoteCustomSettings ];
+    if (options.remoteCustomSettings.length > MAX_ADDITIONAL_SETTINGS)
+      throw new ERR_HTTP2_TOO_MANY_CUSTOM_SETTINGS();
+  }
+
   if (options.maxSessionInvalidFrames !== undefined)
     validateUint32(options.maxSessionInvalidFrames, 'maxSessionInvalidFrames');
 
@@ -3277,6 +3302,13 @@ function connect(authority, options, listener) {
   assertIsObject(options, 'options');
   options = { ...options };
 
+  assertIsArray(options.remoteCustomSettings, 'options.remoteCustomSettings');
+  if (options.remoteCustomSettings) {
+    options.remoteCustomSettings = [ ...options.remoteCustomSettings ];
+    if (options.remoteCustomSettings.length > MAX_ADDITIONAL_SETTINGS)
+      throw new ERR_HTTP2_TOO_MANY_CUSTOM_SETTINGS();
+  }
+
   if (typeof authority === 'string')
     authority = new URL(authority);
 

lib/internal/http2/util.js

@@ -278,8 +278,19 @@ function updateOptionsBuffer(options) {
   optionsBuffer[IDX_OPTIONS_FLAGS] = flags;
 }
 
+function addCustomSettingsToObj() {
+  const toRet = {};
+  const num = settingsBuffer[IDX_SETTINGS_FLAGS + 1];
+  for (let i = 0; i < num; i++) {
+    toRet[settingsBuffer[IDX_SETTINGS_FLAGS + 1 + 2 * i + 1].toString()] =
+       Number(settingsBuffer[IDX_SETTINGS_FLAGS + 1 + 2 * i + 2]);
+  }
+  return toRet;
+}
+
 function getDefaultSettings() {
   settingsBuffer[IDX_SETTINGS_FLAGS] = 0;
+  settingsBuffer[IDX_SETTINGS_FLAGS + 1] = 0; // Length of custom settings
   binding.refreshDefaultSettings();
   const holder = { __proto__: null };
 
@@ -327,6 +338,8 @@ function getDefaultSettings() {
       settingsBuffer[IDX_SETTINGS_ENABLE_CONNECT_PROTOCOL] === 1;
   }
 
+  if (settingsBuffer[IDX_SETTINGS_FLAGS + 1]) holder.customSettings = addCustomSettingsToObj();
+
   return holder;
 }
 
@@ -338,7 +351,7 @@ function getSettings(session, remote) {
   else
     session.localSettings();
 
-  return {
+  const toRet = {
     headerTableSize: settingsBuffer[IDX_SETTINGS_HEADER_TABLE_SIZE],
     enablePush: !!settingsBuffer[IDX_SETTINGS_ENABLE_PUSH],
     initialWindowSize: settingsBuffer[IDX_SETTINGS_INITIAL_WINDOW_SIZE],
@@ -349,6 +362,8 @@ function getSettings(session, remote) {
     enableConnectProtocol:
       !!settingsBuffer[IDX_SETTINGS_ENABLE_CONNECT_PROTOCOL],
   };
+  if (settingsBuffer[IDX_SETTINGS_FLAGS + 1]) toRet.customSettings = addCustomSettingsToObj();
+  return toRet;
 }
 
 function updateSettingsBuffer(settings) {
@@ -415,12 +430,22 @@ function updateSettingsBuffer(settings) {
           }
         }
         if (!set) { // not supported
-          if (numCustomSettings === MAX_ADDITIONAL_SETTINGS)
-            throw new ERR_HTTP2_TOO_MANY_CUSTOM_SETTINGS();
+          let i = 0;
+          while (i < numCustomSettings) {
+            if (settingsBuffer[IDX_SETTINGS_FLAGS + 1 + 2 * i + 1] === nsetting) {
+              settingsBuffer[IDX_SETTINGS_FLAGS + 1 + 2 * i + 2] = val;
+              break;
+            }
+            i++;
+          }
+          if (i === numCustomSettings) {
+            if (numCustomSettings === MAX_ADDITIONAL_SETTINGS)
+              throw new ERR_HTTP2_TOO_MANY_CUSTOM_SETTINGS();
 
-          settingsBuffer[IDX_SETTINGS_FLAGS + 1 + 2 * numCustomSettings + 1] = nsetting;
-          settingsBuffer[IDX_SETTINGS_FLAGS + 1 + 2 * numCustomSettings + 2] = val;
-          numCustomSettings++;
+            settingsBuffer[IDX_SETTINGS_FLAGS + 1 + 2 * numCustomSettings + 1] = nsetting;
+            settingsBuffer[IDX_SETTINGS_FLAGS + 1 + 2 * numCustomSettings + 2] = val;
+            numCustomSettings++;
+          }
         }
       }
     }
@@ -475,6 +500,24 @@ function updateSettingsBuffer(settings) {
   settingsBuffer[IDX_SETTINGS_FLAGS] = flags;
 }
 
+function remoteCustomSettingsToBuffer(remoteCustomSettings) {
+  if (remoteCustomSettings.length > MAX_ADDITIONAL_SETTINGS)
+    throw new ERR_HTTP2_TOO_MANY_CUSTOM_SETTINGS();
+  let numCustomSettings = 0;
+  for (let i = 0; i < remoteCustomSettings.length; i++) {
+    const nsetting = remoteCustomSettings[i];
+    if (typeof nsetting === 'number' && nsetting <= 0xffff &&
+        nsetting >= 0) {
+      settingsBuffer[IDX_SETTINGS_FLAGS + 1 + 2 * numCustomSettings + 1] = nsetting;
+      numCustomSettings++;
+    } else
+      throw new ERR_HTTP2_INVALID_SETTING_VALUE.RangeError(
+        'Range Error', nsetting, 0, 0xffff);
+
+  }
+  settingsBuffer[IDX_SETTINGS_FLAGS + 1] = numCustomSettings;
+}
+
 function getSessionState(session) {
   session.refreshState();
   return {
@@ -649,6 +692,14 @@ const assertIsObject = hideStackFrames((value, name, types) => {
   }
 });
 
+const assertIsArray = hideStackFrames((value, name, types) => {
+  if (value !== undefined &&
+      (value === null ||
+       !ArrayIsArray(value))) {
+    throw new ERR_INVALID_ARG_TYPE.HideStackFramesError(name, types || 'Array', value);
+  }
+});
+
 const assertWithinRange = hideStackFrames(
   (name, value, min = 0, max = Infinity) => {
     if (value !== undefined &&
@@ -732,6 +783,7 @@ function getAuthority(headers) {
 
 module.exports = {
   assertIsObject,
+  assertIsArray,
   assertValidPseudoHeader,
   assertValidPseudoHeaderResponse,
   assertValidPseudoHeaderTrailer,
@@ -747,7 +799,9 @@ module.exports = {
   kProxySocket,
   kRequest,
   mapToHeaders,
+  MAX_ADDITIONAL_SETTINGS,
   NghttpError,
+  remoteCustomSettingsToBuffer,
   sessionName,
   toHeaderObject,
   updateOptionsBuffer,