http2: initialize keepAliveTimeout and keepAliveTimeoutBuffer when allowHTTP1 is true

lib/internal/http2/core.js

@@ -5,6 +5,7 @@ const {
   ArrayIsArray,
   MathMin,
   Number,
+  NumberIsFinite,
   ObjectAssign,
   ObjectDefineProperty,
   ObjectEntries,
@@ -3389,6 +3390,20 @@ class Http2SecureServer extends TLSServer {
       this.headersTimeout = 60_000; // Minimum between 60 seconds or requestTimeout
       this.requestTimeout = 300_000; // 5 minutes
       this.connectionsCheckingInterval = 30_000; // 30 seconds
+      const keepAliveTimeout = options.keepAliveTimeout;
+      if (keepAliveTimeout !== undefined) {
+        validateInteger(keepAliveTimeout, 'keepAliveTimeout', 0);
+        this.keepAliveTimeout = keepAliveTimeout;
+      } else {
+        this.keepAliveTimeout = 5_000; // 5 seconds;
+      }
+      const keepAliveTimeoutBuffer = options.keepAliveTimeoutBuffer;
+      // Optional buffer added to the keep-alive timeout when setting socket timeouts.
+      // Helps reduce ECONNRESET errors from clients by extending the internal timeout.
+      // Default is 1000ms if not specified.
+      const buf = keepAliveTimeoutBuffer;
+      this.keepAliveTimeoutBuffer =
+        (typeof buf === 'number' && NumberIsFinite(buf) && buf >= 0) ? buf : 1000;
       this.shouldUpgradeCallback = function() {
         return this.listenerCount('upgrade') > 0;
       };

test/parallel/test-http2-https-fallback-http-server-options.js

@@ -20,6 +20,9 @@ const ca = fixtures.readKey('fake-startcom-root-cert.pem');
 function onRequest(request, response) {
   const { socket: { alpnProtocol } } = request.httpVersion === '2.0' ?
     request.stream.session : request;
+  // Verify that keepAliveTimeout is set when allowHTTP1 is true
+  assert.strictEqual(typeof request.socket.server.keepAliveTimeout, 'number');
+  assert.strictEqual(request.socket.server.keepAliveTimeout, 5000);
   response.status(200);
   response.end(JSON.stringify({
     alpnProtocol,