dgram: support Uint8Array input to send()

Fixes: #11954
Refs: #11961

doc/api/dgram.md

@@ -245,20 +245,23 @@ chained.
 <!-- YAML
 added: v0.1.99
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/11985
+    description: The `msg` parameter can be an Uint8Array now.
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/10473
+    description: The `address` parameter is always optional now.
   - version: v6.0.0
     pr-url: https://github.com/nodejs/node/pull/5929
     description: On success, `callback` will now be called with an `error`
                  argument of `null` rather than `0`.
-  - version: REPLACEME
-    pr-url: https://github.com/nodejs/node/pull/10473
-    description: The `address` parameter is always optional now.
   - version: v5.7.0
     pr-url: https://github.com/nodejs/node/pull/4374
     description: The `msg` parameter can be an array now. Also, the `offset`
                  and `length` parameters are optional now.
 -->
 
-* `msg` {Buffer|string|array} Message to be sent
+* `msg` {Buffer|Uint8Array|string|array} Message to be sent
 * `offset` {number} Integer. Optional. Offset in the buffer where the message starts.
 * `length` {number} Integer. Optional. Number of bytes in the message.
 * `port` {number} Integer. Destination port.
@@ -269,7 +272,8 @@ Broadcasts a datagram on the socket. The destination `port` and `address` must
 be specified.
 
 The `msg` argument contains the message to be sent.
-Depending on its type, different behavior can apply. If `msg` is a `Buffer`,
+Depending on its type, different behavior can apply. If `msg` is a `Buffer`
+or `Uint8Array`,
 the `offset` and `length` specify the offset within the `Buffer` where the
 message begins and the number of bytes in the message, respectively.
 If `msg` is a `String`, then it is automatically converted to a `Buffer`
@@ -299,7 +303,7 @@ the error is emitted as an `'error'` event on the `socket` object.
 
 Offset and length are optional, but if you specify one you would need to
 specify the other. Also, they are supported only when the first
-argument is a `Buffer`.
+argument is a `Buffer` or `Uint8Array`.
 
 Example of sending a UDP packet to a random port on `localhost`;
 

lib/dgram.js

@@ -29,6 +29,7 @@ const UV_UDP_REUSEADDR = process.binding('constants').os.UV_UDP_REUSEADDR;
 
 const UDP = process.binding('udp_wrap').UDP;
 const SendWrap = process.binding('udp_wrap').SendWrap;
+const { isUint8Array } = process.binding('util');
 
 const BIND_STATE_UNBOUND = 0;
 const BIND_STATE_BINDING = 1;
@@ -266,10 +267,12 @@ Socket.prototype.sendto = function(buffer,
 
 
 function sliceBuffer(buffer, offset, length) {
-  if (typeof buffer === 'string')
+  if (typeof buffer === 'string') {
     buffer = Buffer.from(buffer);
-  else if (!(buffer instanceof Buffer))
-    throw new TypeError('First argument must be a buffer or string');
+  } else if (!isUint8Array(buffer)) {
+    throw new TypeError('First argument must be a Buffer, ' +
+                        'Uint8Array or string');
+  }
 
   offset = offset >>> 0;
   length = length >>> 0;
@@ -285,7 +288,7 @@ function fixBufferList(list) {
     var buf = list[i];
     if (typeof buf === 'string')
       newlist[i] = Buffer.from(buf);
-    else if (!(buf instanceof Buffer))
+    else if (!isUint8Array(buf))
       return null;
     else
       newlist[i] = buf;
@@ -359,8 +362,9 @@ Socket.prototype.send = function(buffer,
   if (!Array.isArray(buffer)) {
     if (typeof buffer === 'string') {
       list = [ Buffer.from(buffer) ];
-    } else if (!(buffer instanceof Buffer)) {
-      throw new TypeError('First argument must be a buffer or a string');
+    } else if (!isUint8Array(buffer)) {
+      throw new TypeError('First argument must be a Buffer, ' +
+                          'Uint8Array or string');
     } else {
       list = [ buffer ];
     }

test/parallel/test-dgram-send-default-host.js

@@ -16,7 +16,7 @@ const received = [];
 client.on('listening', common.mustCall(() => {
   const port = client.address().port;
   client.send(toSend[0], 0, toSend[0].length, port);
-  client.send(toSend[1], port);
+  client.send(new Uint8Array([...toSend[1]]), port);
   client.send([toSend[2]], port);
   client.send(toSend[3], 0, toSend[3].length, port);
 }));