dgram: fix regression in string argument handling

v0.10 allows strings for the offset, length and port arguments to
dgram.send() and dgram.sendto() but master before this commit would
abort with the following assert:

    node: ../../src/udp_wrap.cc:227: static void
    node::UDPWrap::DoSend(const v8::FunctionCallbackInfo<v8::Value>&,
    int): Assertion `args[2]->IsUint32()' failed.

Go beyond what v0.10 does and also add range checks: offset and length
should be >= 0, port should be between 1 and 65535.

That particular change needs to be back-ported to v0.10 because passing
a negative offset or length number aborts with the following assertions:

    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.

Or:

    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 is accepted in v0.10 but
is silently ignored.

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

lib/dgram.js

@@ -252,11 +252,25 @@ Socket.prototype.send = function(buffer,
   if (!util.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);