From 4571c84c6769ada92e07a2a1fec8267bcd2d1459 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
PR-URL: https://github.com/nodejs/node/pull/7066
Reviewed-By: Anna Henningsen <anna@addaleax.net>
---
 lib/dgram.js                                  | 52 ++++++++++++++-----
 .../parallel/test-dgram-close-in-listening.js | 18 +++++++
 2 files changed, 57 insertions(+), 13 deletions(-)
 create mode 100644 test/parallel/test-dgram-close-in-listening.js

diff --git a/lib/dgram.js b/lib/dgram.js
index a2827df0262800..484689380e26eb 100644
--- a/lib/dgram.js
+++ b/lib/dgram.js
@@ -243,6 +243,32 @@ Socket.prototype.sendto = function(buffer,
 };
 
 
+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._queue) {
+    self._queue = [];
+    self.once('listening', clearQueue);
+  }
+  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)
+// send(buffer, offset, length, port)
 Socket.prototype.send = function(buffer,
                                  offset,
                                  length,
@@ -290,18 +316,13 @@ 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) {
-    // 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 < self._sendQueue.length; i++)
-          self.send.apply(self, self._sendQueue[i]);
-        self._sendQueue = undefined;
-      });
-    }
-    self._sendQueue.push([buffer, offset, length, port, address, callback]);
+    enqueue(self, self.send.bind(self,
+                                 buffer,
+                                 offset,
+                                 length,
+                                 port,
+                                 address,
+                                 callback));
     return;
   }
 
@@ -347,10 +368,15 @@ function afterSend(err) {
   this.callback(err, this.length);
 }
 
-
 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..e181f40de67dcf
--- /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
+// will 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');