http2: support ALPNCallback option

PR-URL: #56187
Fixes: #55994
Refs: #45190
Reviewed-By: Tim Perry <pimterry@gmail.com>
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/internal/http2/core.js

@@ -3136,9 +3136,13 @@ function initializeOptions(options) {
 
 function initializeTLSOptions(options, servername) {
   options = initializeOptions(options);
-  options.ALPNProtocols = ['h2'];
-  if (options.allowHTTP1 === true)
-    options.ALPNProtocols.push('http/1.1');
+
+  if (!options.ALPNCallback) {
+    options.ALPNProtocols = ['h2'];
+    if (options.allowHTTP1 === true)
+      options.ALPNProtocols.push('http/1.1');
+  }
+
   if (servername !== undefined && !options.servername)
     options.servername = servername;
   return options;

test/parallel/test-http2-alpn.js

@@ -0,0 +1,47 @@
+'use strict';
+const common = require('../common');
+const fixtures = require('../common/fixtures');
+
+// This test verifies that http2 server support ALPNCallback option.
+
+if (!common.hasCrypto) common.skip('missing crypto');
+
+const assert = require('assert');
+const h2 = require('http2');
+const tls = require('tls');
+
+{
+  // Server sets two incompatible ALPN options:
+  assert.throws(() => h2.createSecureServer({
+    ALPNCallback: () => 'a',
+    ALPNProtocols: ['b', 'c']
+  }), (error) => error.code === 'ERR_TLS_ALPN_CALLBACK_WITH_PROTOCOLS');
+}
+
+{
+  const server = h2.createSecureServer({
+    key: fixtures.readKey('rsa_private.pem'),
+    cert: fixtures.readKey('rsa_cert.crt'),
+    ALPNCallback: () => 'a',
+  });
+
+  server.on(
+    'secureConnection',
+    common.mustCall((socket) => {
+      assert.strictEqual(socket.alpnProtocol, 'a');
+      socket.end();
+      server.close();
+    })
+  );
+
+  server.listen(0, function() {
+    const client = tls.connect({
+      port: server.address().port,
+      rejectUnauthorized: false,
+      ALPNProtocols: ['a'],
+    }, common.mustCall(() => {
+      assert.strictEqual(client.alpnProtocol, 'a');
+      client.end();
+    }));
+  });
+}