dgram: support for setting socket buffer size

* setRecvBufferSize(int) and setSendBufferSize(int)
* added docs for send/receive buffer sizes
* Added options support to set buffer sizes in
  dgram.createSocket().

PR-URL: https://github.com/nodejs/node/pull/13623
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

1 files changed, 74 insertions, 0 deletions

diff --git a/test/parallel/test-dgram-socket-buffer-size.js b/test/parallel/test-dgram-socket-buffer-size.js
new file mode 100644
index 0000000000..13fbd4fb4b
--- /dev/null
+++ b/test/parallel/test-dgram-socket-buffer-size.js
@@ -0,0 +1,74 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const dgram = require('dgram');
+
+{
+  // Should throw error if the socket is never bound.
+  const errorObj = {
+    code: 'ERR_SOCKET_BUFFER_SIZE',
+    type: Error,
+    message: /^Could not get or set buffer size:.*$/
+  };
+
+  const socket = dgram.createSocket('udp4');
+
+  assert.throws(() => {
+    socket.setRecvBufferSize(8192);
+  }, common.expectsError(errorObj));
+
+  assert.throws(() => {
+    socket.setSendBufferSize(8192);
+  }, common.expectsError(errorObj));
+
+  assert.throws(() => {
+    socket.getRecvBufferSize();
+  }, common.expectsError(errorObj));
+
+  assert.throws(() => {
+    socket.getSendBufferSize();
+  }, common.expectsError(errorObj));
+}
+
+{
+  // Should throw error if invalid buffer size is specified
+  const errorObj = {
+    code: 'ERR_SOCKET_BAD_BUFFER_SIZE',
+    type: TypeError,
+    message: /^Buffer size must be a positive integer$/
+  };
+
+  const badBufferSizes = [-1, Infinity, 'Doh!'];
+
+  const socket = dgram.createSocket('udp4');
+
+  socket.bind(common.mustCall(() => {
+    badBufferSizes.forEach((badBufferSize) => {
+      assert.throws(() => {
+        socket.setRecvBufferSize(badBufferSize);
+      }, common.expectsError(errorObj));
+
+      assert.throws(() => {
+        socket.setSendBufferSize(badBufferSize);
+      }, common.expectsError(errorObj));
+    });
+    socket.close();
+  }));
+}
+
+{
+  // Can set and get buffer sizes after binding the socket.
+  const socket = dgram.createSocket('udp4');
+
+  socket.bind(common.mustCall(() => {
+    socket.setRecvBufferSize(10000);
+    socket.setSendBufferSize(10000);
+
+    // note: linux will double the buffer size
+    const expectedBufferSize = common.isLinux ? 20000 : 10000;
+    assert.strictEqual(socket.getRecvBufferSize(), expectedBufferSize);
+    assert.strictEqual(socket.getSendBufferSize(), expectedBufferSize);
+    socket.close();
+  }));
+}