dns: add channel.cancel()

This can be used to implement custom timeouts.

Fixes: https://github.com/nodejs/node/issues/7231
PR-URL: https://github.com/nodejs/node/pull/14518
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

1 files changed, 29 insertions, 0 deletions

diff --git a/test/parallel/test-dns-channel-cancel.js b/test/parallel/test-dns-channel-cancel.js
new file mode 100644
index 0000000000..797d61efb4
--- /dev/null
+++ b/test/parallel/test-dns-channel-cancel.js
@@ -0,0 +1,29 @@
+'use strict';
+const common = require('../common');
+const dnstools = require('../common/dns');
+const { Resolver } = require('dns');
+const assert = require('assert');
+const dgram = require('dgram');
+
+const server = dgram.createSocket('udp4');
+const resolver = new Resolver();
+
+server.bind(0, common.mustCall(() => {
+  resolver.setServers([`127.0.0.1:${server.address().port}`]);
+  resolver.resolve4('example.org', common.mustCall((err, res) => {
+    assert.strictEqual(err.code, 'ECANCELLED');
+    assert.strictEqual(err.errno, 'ECANCELLED');
+    assert.strictEqual(err.syscall, 'queryA');
+    assert.strictEqual(err.hostname, 'example.org');
+    server.close();
+  }));
+}));
+
+server.on('message', common.mustCall((msg, { address, port }) => {
+  const parsed = dnstools.parseDNSPacket(msg);
+  const domain = parsed.questions[0].domain;
+  assert.strictEqual(domain, 'example.org');
+
+  // Do not send a reply.
+  resolver.cancel();
+}));