From 0e094acf5bed6a847c655fc69c33067e29227f60 Mon Sep 17 00:00:00 2001
From: Matteo Collina <hello@matteocollina.com>
Date: Mon, 30 May 2016 18:29:27 +0200
Subject: [PATCH] dgram: generalized send queue to handle close

If the udp socket is not ready and we are accumulating
messages to send, it needs to delay closing the socket when
all messages are flushed.

Fixes: https://github.com/nodejs/node/issues/7061
---
 lib/dgram.js                                  | 32 ++++++++++++-------
 .../parallel/test-dgram-close-in-listening.js | 18 +++++++++++
 2 files changed, 39 insertions(+), 11 deletions(-)
 create mode 100644 test/parallel/test-dgram-close-in-listening.js

diff --git a/lib/dgram.js b/lib/dgram.js
index e6cc169dc644fe..c088bffa7ff477 100644
--- a/lib/dgram.js
+++ b/lib/dgram.js
@@ -283,20 +283,25 @@ function fixBufferList(list) {
 function enqueue(self, toEnqueue) {
   // If the send queue hasn't been initialized yet, do it, and install an
   // event handler that flushes the send queue after binding is done.
-  if (!self._sendQueue) {
-    self._sendQueue = [];
-    self.once('listening', function() {
-      // Flush the send queue.
-      for (var i = 0; i < this._sendQueue.length; i++)
-        this.send.apply(self, this._sendQueue[i]);
-      this._sendQueue = undefined;
-    });
+  if (!self._queue) {
+    self._queue = [];
+    self.once('listening', clearQueue);
   }
-  self._sendQueue.push(toEnqueue);
+  self._queue.push(toEnqueue);
   return;
 }
 
 
+function clearQueue() {
+  const queue = this._queue;
+  this._queue = undefined;
+
+  // Flush the send queue.
+  for (var i = 0; i < queue.length; i++)
+    queue[i]();
+}
+
+
 // valid combinations
 // send(buffer, offset, length, port, address, callback)
 // send(buffer, offset, length, port, address)
@@ -353,7 +358,7 @@ Socket.prototype.send = function(buffer,
   // If the socket hasn't been bound yet, push the outbound packet onto the
   // send queue and send after binding is complete.
   if (self._bindState != BIND_STATE_BOUND) {
-    enqueue(self, [list, port, address, callback]);
+    enqueue(self, self.send.bind(self, list, port, address, callback));
     return;
   }
 
@@ -407,10 +412,15 @@ function afterSend(err, sent) {
   this.callback(err, sent);
 }
 
-
 Socket.prototype.close = function(callback) {
   if (typeof callback === 'function')
     this.on('close', callback);
+
+  if (this._queue) {
+    this._queue.push(this.close.bind(this));
+    return this;
+  }
+
   this._healthCheck();
   this._stopReceiving();
   this._handle.close();
diff --git a/test/parallel/test-dgram-close-in-listening.js b/test/parallel/test-dgram-close-in-listening.js
new file mode 100644
index 00000000000000..f67d49b36e8a20
--- /dev/null
+++ b/test/parallel/test-dgram-close-in-listening.js
@@ -0,0 +1,18 @@
+'use strict';
+// Ensure that if a dgram socket is closed before the sendQueue is drained
+// wil not crash
+
+const common = require('../common');
+const dgram = require('dgram');
+
+const buf = Buffer.alloc(1024, 42);
+
+const socket = dgram.createSocket('udp4');
+
+socket.on('listening', function() {
+  socket.close();
+});
+
+// adds a listener to 'listening' to send the data when
+// the socket is available
+socket.send(buf, 0, buf.length, common.PORT, 'localhost');