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dgram: add custom lookup function in sockets

This commit adds support for custom DNS lookup functions in
dgram sockets. This is similar to the existing feature in net
sockets.

Refs: #6189
PR-URL: #14560
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Wyatt Preul <wpreul@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
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cjihrig committed Aug 1, 2017
1 parent 46c3dd7 commit 5a050550d377c53a9249f218888ea2e92a4d48dc
Showing with 86 additions and 31 deletions.
  1. +21 −17 doc/api/dgram.md
  2. +18 −14 lib/dgram.js
  3. +47 −0 test/parallel/test-dgram-custom-lookup.js
View
@@ -455,27 +455,30 @@ s.bind(1234, () => {
### dgram.createSocket(options[, callback])
<!-- YAML
added: v0.11.13
changes:
- version: REPLACEME
pr-url: https://github.com/nodejs/node/pull/14560
description: The `lookup` option is supported.
-->
* `options` {Object}
* `callback` {Function} Attached as a listener to `'message'` events.
* `options` {Object} Available options are:
* `type` {string} The family of socket. Must be either `'udp4'` or `'udp6'`.
Required.
* `reuseAddr` {boolean} When `true` [`socket.bind()`][] will reuse the
address, even if another process has already bound a socket on it. Optional.
Defaults to `false`.
* `lookup` {Function} Custom lookup function. Defaults to [`dns.lookup()`][].
Optional.
* `callback` {Function} Attached as a listener for `'message'` events. Optional.
* Returns: {dgram.Socket}
Creates a `dgram.Socket` object. The `options` argument is an object that
should contain a `type` field of either `udp4` or `udp6` and an optional
boolean `reuseAddr` field.
When `reuseAddr` is `true` [`socket.bind()`][] will reuse the address, even if
another process has already bound a socket on it. `reuseAddr` defaults to
`false`. The optional `callback` function is added as a listener for `'message'`
events.
Once the socket is created, calling [`socket.bind()`][] will instruct the
socket to begin listening for datagram messages. When `address` and `port` are
not passed to [`socket.bind()`][] the method will bind the socket to the "all
interfaces" address on a random port (it does the right thing for both `udp4`
and `udp6` sockets). The bound address and port can be retrieved using
[`socket.address().address`][] and [`socket.address().port`][].
Creates a `dgram.Socket` object. Once the socket is created, calling
[`socket.bind()`][] will instruct the socket to begin listening for datagram
messages. When `address` and `port` are not passed to [`socket.bind()`][] the
method will bind the socket to the "all interfaces" address on a random port
(it does the right thing for both `udp4` and `udp6` sockets). The bound address
and port can be retrieved using [`socket.address().address`][] and
[`socket.address().port`][].
### dgram.createSocket(type[, callback])
<!-- YAML
@@ -505,6 +508,7 @@ and `udp6` sockets). The bound address and port can be retrieved using
[`cluster`]: cluster.html
[`dgram.Socket#bind()`]: #dgram_socket_bind_options_callback
[`dgram.createSocket()`]: #dgram_dgram_createsocket_options_callback
[`dns.lookup()`]: dns.html#dns_dns_lookup_hostname_options_callback
[`socket.address().address`]: #dgram_socket_address
[`socket.address().port`]: #dgram_socket_address
[`socket.bind()`]: #dgram_socket_bind_port_address_callback
View
@@ -46,31 +46,32 @@ var cluster = null;
const errnoException = util._errnoException;
const exceptionWithHostPort = util._exceptionWithHostPort;
function lookup(address, family, callback) {
return dns.lookup(address, family, callback);
}
function lookup4(address, callback) {
function lookup4(lookup, address, callback) {
return lookup(address || '127.0.0.1', 4, callback);
}
function lookup6(address, callback) {
function lookup6(lookup, address, callback) {
return lookup(address || '::1', 6, callback);
}
function newHandle(type) {
function newHandle(type, lookup) {
if (lookup === undefined)
lookup = dns.lookup;
else if (typeof lookup !== 'function')
throw new errors.TypeError('ERR_INVALID_ARG_TYPE', 'lookup', 'function');
if (type === 'udp4') {
const handle = new UDP();
handle.lookup = lookup4;
handle.lookup = lookup4.bind(handle, lookup);
return handle;
}
if (type === 'udp6') {
const handle = new UDP();
handle.lookup = lookup6;
handle.lookup = lookup6.bind(handle, lookup);
handle.bind = handle.bind6;
handle.send = handle.send6;
return handle;
@@ -100,13 +101,15 @@ function _createSocketHandle(address, port, addressType, fd, flags) {
function Socket(type, listener) {
EventEmitter.call(this);
var lookup;
if (type !== null && typeof type === 'object') {
var options = type;
type = options.type;
lookup = options.lookup;
}
var handle = newHandle(type);
var handle = newHandle(type, lookup);
handle.owner = this;
this._handle = handle;
@@ -186,10 +189,11 @@ Socket.prototype.bind = function(port_, address_ /*, callback*/) {
}
// defaulting address for bind to all interfaces
if (!address && this._handle.lookup === lookup4) {
address = '0.0.0.0';
} else if (!address && this._handle.lookup === lookup6) {
address = '::';
if (!address) {
if (this.type === 'udp4')
address = '0.0.0.0';
else
address = '::';
}
// resolve address first
@@ -0,0 +1,47 @@
'use strict';
const common = require('../common');
const assert = require('assert');
const dgram = require('dgram');
const dns = require('dns');
{
// Verify that the provided lookup function is called.
const lookup = common.mustCall((host, family, callback) => {
dns.lookup(host, family, callback);
});
const socket = dgram.createSocket({ type: 'udp4', lookup });
socket.bind(common.mustCall(() => {
socket.close();
}));
}
{
// Verify that lookup defaults to dns.lookup().
const originalLookup = dns.lookup;
dns.lookup = common.mustCall((host, family, callback) => {
dns.lookup = originalLookup;
originalLookup(host, family, callback);
});
const socket = dgram.createSocket({ type: 'udp4' });
socket.bind(common.mustCall(() => {
socket.close();
}));
}
{
// Verify that non-functions throw.
[null, true, false, 0, 1, NaN, '', 'foo', {}, Symbol()].forEach((value) => {
assert.throws(() => {
dgram.createSocket({ type: 'udp4', lookup: value });
}, common.expectsError({
code: 'ERR_INVALID_ARG_TYPE',
type: TypeError,
message: 'The "lookup" argument must be of type function'
}));
});
}

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