dgram: fix assertion on bad send() arguments

Add range checks for the offset, length and port arguments to
dgram.Socket#send().  Fixes the following assertion:

    node: ../../src/udp_wrap.cc:264: static v8::Handle<v8::Value>
    node::UDPWrap::DoSend(const v8::Arguments&, int): Assertion
    `offset < Buffer::Length(buffer_obj)' failed.

And:

    node: ../../src/udp_wrap.cc:265: static v8::Handle<v8::Value>
    node::UDPWrap::DoSend(const v8::Arguments&, int): Assertion
    `length <= Buffer::Length(buffer_obj) - offset' failed.

Interestingly enough, a negative port number was accepted until now but
silently ignored.  (In other words, it would send the datagram to a
random port.)

This commit exposed a bug in the simple/test-dgram-close test which
has also been fixed.

This is a back-port of commit 41ec6d0 from the master branch.

Fixes #6025.

lib/dgram.js

@@ -244,11 +244,25 @@ Socket.prototype.send = function(buffer,
   if (!Buffer.isBuffer(buffer))
     throw new TypeError('First argument must be a buffer object.');
 
+  offset = offset | 0;
+  if (offset < 0)
+    throw new RangeError('Offset should be >= 0');
+
   if (offset >= buffer.length)
-    throw new Error('Offset into buffer too large');
+    throw new RangeError('Offset into buffer too large');
+
+  // Sending a zero-length datagram is kind of pointless but it _is_
+  // allowed, hence check that length >= 0 rather than > 0.
+  length = length | 0;
+  if (length < 0)
+    throw new RangeError('Length should be >= 0');
 
   if (offset + length > buffer.length)
-    throw new Error('Offset + length beyond buffer length');
+    throw new RangeError('Offset + length beyond buffer length');
+
+  port = port | 0;
+  if (port <= 0 || port > 65535)
+    throw new RangeError('Port should be > 0 and < 65536');
 
   callback = callback || noop;
 

test/simple/test-dgram-close.js

@@ -30,6 +30,5 @@ var buf = new Buffer(1024);
 buf.fill(42);
 
 var socket = dgram.createSocket('udp4');
-
-socket.send(buf, 0, buf.length, common.port, 'localhost');
+socket.send(buf, 0, buf.length, common.PORT, 'localhost');
 socket.close();

test/simple/test-dgram-send-bad-arguments.js

@@ -0,0 +1,40 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var common = require('../common');
+var assert = require('assert');
+var dgram = require('dgram');
+
+var buf = Buffer('test');
+var host = '127.0.0.1';
+var sock = dgram.createSocket('udp4');
+
+assert.throws(function() {
+  sock.send();
+}, TypeError);  // First argument should be a buffer.
+
+assert.throws(function() { sock.send(buf, -1, 1, 1, host);    }, RangeError);
+assert.throws(function() { sock.send(buf, 1, -1, 1, host);    }, RangeError);
+assert.throws(function() { sock.send(buf, 1, 1, -1, host);    }, RangeError);
+assert.throws(function() { sock.send(buf, 5, 1, 1, host);     }, RangeError);
+assert.throws(function() { sock.send(buf, 1, 5, 1, host);     }, RangeError);
+assert.throws(function() { sock.send(buf, 1, 1, 0, host);     }, RangeError);
+assert.throws(function() { sock.send(buf, 1, 1, 65536, host); }, RangeError);