Add callback to dgramSocket.send()

lib/dgram.js

@@ -146,17 +146,33 @@ Socket.prototype.address = function () {
 Socket.prototype.send = function(port, addr, buffer, offset, length) {
   var self = this;
 
+  var lastArg = arguments[arguments.length - 1];
+  var callback = typeof lastArg === 'function' ? lastArg : null;
+
   if (!isPort(arguments[0])) {
+    try {
       if (!self.fd) {
         self.type = 'unix_dgram';
         self.fd = socket(self.type);
       }
-    sendto(self.fd, buffer, offset, length, 0, port, addr);
+      var bytes = sendto(self.fd, buffer, offset, length, 0, port, addr);
+    } catch (e) {
+      if (callback) callback(e);
+      return;
+    }
+
+    if (callback) callback(null, bytes);
+
   } else {
     dns.lookup(arguments[1], function (err, ip, addressType) {
+      // DNS error
       if (err) {
+        if (callback) callback(err);
         self.emit('error', err);
-      } else {
+        return;
+      }
+
+      try {
         if (!self.fd) {
           self.type = addressType == 4 ? 'udp4' : 'udp6';
           self.fd = socket(self.type);
@@ -165,8 +181,14 @@ Socket.prototype.send = function(port, addr, buffer, offset, length) {
             self._startWatcher();
           });
         }
-        sendto(self.fd, buffer, offset, length, 0, port, ip);
+        var bytes = sendto(self.fd, buffer, offset, length, 0, port, ip);
+      } catch (err) {
+        // socket creation, or sendto error.
+        if (callback) callback(err);
+        return;
       }
+
+      if (callback) callback(null, bytes);
     });
   }
 };

test/simple/test-dgram-pingpong.js

@@ -4,7 +4,9 @@ var dgram = require("dgram");
 
 var tests_run = 0;
 
+
 function pingPongTest (port, host) {
+  var callbacks = 0;
   var N = 500;
   var count = 0;
   var sent_final_ping = false;
@@ -17,7 +19,9 @@ function pingPongTest (port, host) {
     if (/PING/.exec(msg)) {
       var buf = new Buffer(4);
       buf.write('PONG');
-      server.send(rinfo.port, rinfo.address, buf, 0, buf.length);
+      server.send(rinfo.port, rinfo.address, buf, 0, buf.length, function (err, sent) {
+        callbacks++;
+      });
     }
 
   });
@@ -58,6 +62,7 @@ function pingPongTest (port, host) {
       assert.equal(N, count);
       tests_run += 1;
       server.close();
+      assert.equal(N-1, callbacks);
     });
 
     client.addListener("error", function (e) {