http2: Emit unknownProtocol event or silently destroy the socket (Squash)

Author: sebdeckers

doc/api/http2.md

@@ -685,6 +685,13 @@ The `'socketError'` event is emitted when an `'error'` event is emitted by
 a `Socket` associated with the server. If no listener is registered for this
 event, an `'error'` event is emitted on the `Socket` instance instead.
 
+#### Event: 'unknownProtocol'
+
+The `'unknownProtocol'` event is emitted when a connecting client fails to
+negotiate an allowed protocol (i.e. HTTP/2 or HTTP/1.1). The event handler
+receives the socket for handling. If no listener is registered for this event,
+the connection is terminated. See the 
+
 #### Event: 'stream'
 
 The `'stream'` event is emitted when a `'stream'` event has been emitted by
@@ -799,9 +806,7 @@ server.listen(80);
 * `options` {Object}
   * `allowHTTP1` {boolean} Incoming client connections that do not support
     HTTP/2 will be downgraded to HTTP/1.x when set to `true`. The default value
-    is `false`, which rejects non-HTTP/2 client connections by either emitting
-    a `'socketError'` event, if a handler is registered, or else disconnecing
-    the remote peer and emitting an `'error'` event on the socket.
+    is `false`. See the [`'unknownProtocol'`][] event.
   * `maxDefaultDynamicTableSize` {number} (TODO: Add detail)
   * `maxReservedRemoteStreams` {number} (TODO: Add detail)
   * `maxSendHeaderBlockLength` {number} (TODO: Add detail)
@@ -1014,3 +1019,4 @@ TBD
 [ServerHttp2Stream]: #http2_class_serverhttp2stream
 [Settings Object]: #http2_settings_object
 [Using options.selectPadding]: #http2_using_options_selectpadding
+[`'unknownProtocol'`]: #http2_event_unknownprotocol

lib/internal/errors.js

@@ -181,7 +181,6 @@ E('ERR_SOCKET_BAD_TYPE',
 E('ERR_SOCKET_CANNOT_SEND', 'Unable to send data');
 E('ERR_SOCKET_BAD_PORT', 'Port should be > 0 and < 65536');
 E('ERR_SOCKET_DGRAM_NOT_RUNNING', 'Not running');
-E('ERR_SOCKET_REJECT_HTTP1', 'HTTP/1 not allowed');
 // Add new errors from here...
 
 function invalidArgType(name, expected, actual) {

lib/internal/http2/core.js

@@ -1627,12 +1627,12 @@ function connectionListener(socket) {
     if (options.allowHTTP1 === true) {
       // Fallback to HTTP/1.1
       return httpConnectionListener.call(this, socket);
+    } else if (this.emit('unknownProtocol', socket)) {
+      // Let event handler deal with the socket
+      return;
     } else {
       // Reject non-HTTP/2 client
-      return process.nextTick(
-        socketOnError.bind(socket),
-        new errors.TypeError('ERR_SOCKET_REJECT_HTTP1')
-      );
+      return socket.destroy();
     }
   }
 

test/parallel/test-http2-https-fallback.js

@@ -128,14 +128,9 @@ function onSession(session) {
     mustCall(onRequest)
   );
 
-  const expectedRejection = mustCall(expectsError({
-    code: 'ERR_SOCKET_REJECT_HTTP1',
-    type: TypeError,
-    message: 'HTTP/1 not allowed'
-  }), 2);
-  server.on('secureConnection', mustCall((socket) => {
-    socket.on('error', expectedRejection);
-  }, 3));
+  server.on('unknownProtocol', mustCall((socket) => {
+    socket.destroy();
+  }, 2));
 
   server.listen(0);