dgram: implicit binds should be exclusive

Server sockets should be shared by default, and client sockets should be
exclusive by default. For net/TCP, this is how it is, for dgram/UDP, its
a little less clear what a client socket is, but a socket that is
auto-bound during a dgram.send() is not usefully shared among cluster
workers, any more than an outgoing TCP connection would be usefully
shared.

Since implicit binds become exclusive, implicit/client dgram sockets can
now be used with cluster on Windows. Before, neither explicit nor
implicitly bound sockets could be used, causing dgram to be completely
unsupported with cluster on Windows. After this change, they become half
supported.

PR: https://github.com/iojs/io.js/pull/325
PR: https://github.com/joyent/node/pull/8643
Reviewed-by: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-by: Bert Belder <bertbelder@gmail.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/test/parallel/test-cluster-dgram-2.js b/test/parallel/test-cluster-dgram-2.js
index 6b88a18dc2..68de38e7c3 100644
--- a/test/parallel/test-cluster-dgram-2.js
+++ b/test/parallel/test-cluster-dgram-2.js
@@ -53,6 +53,11 @@ function worker() {
   var socket = dgram.createSocket('udp4');
   var buf = new Buffer('hello world');
 
+  // This test is intended to exercise the cluster binding of udp sockets, but
+  // since sockets aren't clustered when implicitly bound by at first call of
+  // send(), explicitly bind them to an ephemeral port.
+  socket.bind(0);
+
   for (var i = 0; i < PACKETS_PER_WORKER; i++)
     socket.send(buf, 0, buf.length, common.PORT, '127.0.0.1');