dgram: handle default address case when offset and length are specified

Fixes a regression introduced by: https://github.com/nodejs/node/pull/4374.
Adds a new test to avoid similar issue in the future.
The test is disabled on windows, because this feature never worked
there.

Fixes: https://github.com/nodejs/node/issues/5398
Reviewed-By: Roman Reiss <me@silverwind.io>
Reviewed-By: Rod Vagg <rod@vagg.org>
Reviewed-By: Evan Lucas <evanlucas@me.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/lib/dgram.js b/lib/dgram.js
index 279f595269..6937ab6362 100644
--- a/lib/dgram.js
+++ b/lib/dgram.js
@@ -286,6 +286,13 @@ function enqueue(self, toEnqueue) {
 }
 
 
+// valid combinations
+// send(buffer, offset, length, port, address, callback)
+// send(buffer, offset, length, port, address)
+// send(buffer, offset, length, port)
+// send(bufferOrList, port, address, callback)
+// send(bufferOrList, port, address)
+// send(bufferOrList, port)
 Socket.prototype.send = function(buffer,
                                  offset,
                                  length,
@@ -294,8 +301,7 @@ Socket.prototype.send = function(buffer,
                                  callback) {
   var self = this;
 
-  // same as arguments.length === 5 || arguments.length === 6
-  if (address) {
+  if (address || (port && typeof port !== 'function')) {
     buffer = sliceBuffer(buffer, offset, length);
   } else {
     callback = port;