From 3d39be73d470ca57094ca8c98be5e2ee7126ab66 Mon Sep 17 00:00:00 2001
From: Anna Henningsen <anna@addaleax.net>
Date: Fri, 1 Nov 2019 19:50:40 +0100
Subject: [PATCH] dgram: remove listeners on bind error

This avoids piling up `'listening'` event listeners if
`.bind()` fails repeatedly.

Fixes: https://github.com/nodejs/node/issues/30209

PR-URL: https://github.com/nodejs/node/pull/30210
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
---
 lib/dgram.js                                  | 17 ++++++++++--
 test/parallel/test-dgram-bind-error-repeat.js | 27 +++++++++++++++++++
 2 files changed, 42 insertions(+), 2 deletions(-)
 create mode 100644 test/parallel/test-dgram-bind-error-repeat.js

diff --git a/lib/dgram.js b/lib/dgram.js
index c365df2414f99d..ae260ba437bf54 100644
--- a/lib/dgram.js
+++ b/lib/dgram.js
@@ -211,8 +211,21 @@ Socket.prototype.bind = function(port_, address_ /* , callback */) {
 
   state.bindState = BIND_STATE_BINDING;
 
-  if (arguments.length && typeof arguments[arguments.length - 1] === 'function')
-    this.once('listening', arguments[arguments.length - 1]);
+  const cb = arguments.length && arguments[arguments.length - 1];
+  if (typeof cb === 'function') {
+    function removeListeners() {
+      this.removeListener('error', removeListeners);
+      this.removeListener('listening', onListening);
+    }
+
+    function onListening() {
+      removeListeners.call(this);
+      cb.call(this);
+    }
+
+    this.on('error', removeListeners);
+    this.on('listening', onListening);
+  }
 
   if (port instanceof UDP) {
     replaceHandle(this, port);
diff --git a/test/parallel/test-dgram-bind-error-repeat.js b/test/parallel/test-dgram-bind-error-repeat.js
new file mode 100644
index 00000000000000..a520d30a519cd2
--- /dev/null
+++ b/test/parallel/test-dgram-bind-error-repeat.js
@@ -0,0 +1,27 @@
+'use strict';
+const common = require('../common');
+const dgram = require('dgram');
+
+// Regression test for https://github.com/nodejs/node/issues/30209
+// No warning should be emitted when re-trying `.bind()` on UDP sockets
+// repeatedly.
+
+process.on('warning', common.mustNotCall());
+
+const reservePortSocket = dgram.createSocket('udp4');
+reservePortSocket.bind(() => {
+  const { port } = reservePortSocket.address();
+
+  const newSocket = dgram.createSocket('udp4');
+
+  let errors = 0;
+  newSocket.on('error', common.mustCall(() => {
+    if (++errors < 20) {
+      newSocket.bind(port, common.mustNotCall());
+    } else {
+      newSocket.close();
+      reservePortSocket.close();
+    }
+  }, 20));
+  newSocket.bind(port, common.mustNotCall());
+});