From 592be014b680b70ee349dda5aa5928bde28da2cd Mon Sep 17 00:00:00 2001
From: Fedor Indutny <fedor@indutny.com>
Date: Wed, 9 Apr 2014 03:04:53 +0400
Subject: [PATCH] dgram: introduce `reuseAddr` option

Introduce new signature for both `dgram.createSocket` method and
`dgram.Socket` constructor:

    dgram.createSocket(options, [listener])

Options should contain `type` property and may contain `reuseAddr`
property. When `reuseAddr` is `true` - SO_REUSEADDR will be issued on
socket on bind.

fix #7415

Signed-off-by: Fedor Indutny <fedor@indutny.com>
---
 doc/api/dgram.markdown                            |  7 ++++++-
 lib/dgram.js                                      | 15 ++++++++++++++-
 src/node_constants.cc                             |  5 +++++
 test/simple/test-dgram-broadcast-multi-process.js | 10 ++++++++--
 4 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/doc/api/dgram.markdown b/doc/api/dgram.markdown
index 5ce26de8d42..b659e6b1a97 100644
--- a/doc/api/dgram.markdown
+++ b/doc/api/dgram.markdown
@@ -22,8 +22,13 @@ You have to change it to this:
 
 
 ## dgram.createSocket(type, [callback])
+## dgram.createSocket(options, [callback])
 
 * `type` String. Either 'udp4' or 'udp6'
+* `options` Object. Should contain a `type` property and could contain
+  `reuseAddr` property. `false` by default.
+  When `reuseAddr` is `true` - `socket.bind()` will reuse address, even if the
+  other process has already bound a socket on it.
 * `callback` Function. Attached as a listener to `message` events.
   Optional
 * Returns: Socket object
@@ -41,7 +46,7 @@ with `socket.address().address` and `socket.address().port`.
 ## Class: dgram.Socket
 
 The dgram Socket class encapsulates the datagram functionality.  It
-should be created via `dgram.createSocket(type, [callback])`.
+should be created via `dgram.createSocket(...)`
 
 ### Event: 'message'
 
diff --git a/lib/dgram.js b/lib/dgram.js
index 3a44707e03e..6ff8cf25138 100644
--- a/lib/dgram.js
+++ b/lib/dgram.js
@@ -22,6 +22,7 @@
 var assert = require('assert');
 var util = require('util');
 var events = require('events');
+var constants = require('constants');
 
 var UDP = process.binding('udp_wrap').UDP;
 
@@ -96,6 +97,11 @@ exports._createSocketHandle = function(address, port, addressType, fd) {
 function Socket(type, listener) {
   events.EventEmitter.call(this);
 
+  if (typeof type === 'object') {
+    var options = type;
+    type = options.type;
+  }
+
   var handle = newHandle(type);
   handle.owner = this;
 
@@ -105,6 +111,9 @@ function Socket(type, listener) {
   this.type = type;
   this.fd = null; // compatibility hack
 
+  // If true - UV_UDP_REUSEADDR flag will be set
+  this._reuseAddr = options && options.reuseAddr;
+
   if (util.isFunction(listener))
     this.on('message', listener);
 }
@@ -196,7 +205,11 @@ Socket.prototype.bind = function(/*port, address, callback*/) {
       if (!self._handle)
         return; // handle has been closed in the mean time
 
-      var err = self._handle.bind(ip, port || 0, /*flags=*/ 0);
+      var flags = 0;
+      if (self._reuseAddr)
+        flags |= constants.UV_UDP_REUSEADDR;
+
+      var err = self._handle.bind(ip, port || 0, flags);
       if (err) {
         self.emit('error', errnoException(err, 'bind'));
         self._bindState = BIND_STATE_UNBOUND;
diff --git a/src/node_constants.cc b/src/node_constants.cc
index c903dd90ea3..9e9881e0a7a 100644
--- a/src/node_constants.cc
+++ b/src/node_constants.cc
@@ -1071,12 +1071,17 @@ void DefineSystemConstants(Handle<Object> target) {
 #endif
 }
 
+void DefineUVConstants(Handle<Object> target) {
+  NODE_DEFINE_CONSTANT(target, UV_UDP_REUSEADDR);
+}
+
 void DefineConstants(Handle<Object> target) {
   DefineErrnoConstants(target);
   DefineWindowsErrorConstants(target);
   DefineSignalConstants(target);
   DefineOpenSSLConstants(target);
   DefineSystemConstants(target);
+  DefineUVConstants(target);
 }
 
 }  // namespace node
diff --git a/test/simple/test-dgram-broadcast-multi-process.js b/test/simple/test-dgram-broadcast-multi-process.js
index ad5b4eba82d..4d9eebc1012 100644
--- a/test/simple/test-dgram-broadcast-multi-process.js
+++ b/test/simple/test-dgram-broadcast-multi-process.js
@@ -157,7 +157,10 @@ if (process.argv[2] !== 'child') {
     })(x);
   }
 
-  var sendSocket = dgram.createSocket('udp4');
+  var sendSocket = dgram.createSocket({
+    type: 'udp4',
+    reuseAddr: true
+  });
 
   // bind the address explicitly for sending
   // INADDR_BROADCAST to only one interface
@@ -201,7 +204,10 @@ if (process.argv[2] !== 'child') {
 
 if (process.argv[2] === 'child') {
   var receivedMessages = [];
-  var listenSocket = dgram.createSocket('udp4');
+  var listenSocket = dgram.createSocket({
+    type: 'udp4',
+    reuseAddr: true
+  });
 
   listenSocket.on('message', function(buf, rinfo) {
     // receive udp messages only sent from parent