PTR records implementation

README.md

@@ -2,7 +2,7 @@
 
 Node-named is a lightweight DNS server written in pure javascript. It has
 limited support for the DNS spec, but aims to implement all of the *common*
-functionality that is in use today. 
+functionality that is in use today.
 
 ** This project is not actively maintained **
 I've received a lot of great PRs for this project, but I don't have the capacity to actively maintain this library at the moment. I feel strongly about maintaining backwards compatibility for people who rely on it, so any PRs would also need to adhere to keeping the API sane, or contribute to some improvement in performance.
@@ -29,15 +29,15 @@ server.on('query', function(query) {
 ```
 ## Creating DNS Records
 
-node-named provides helper functions for creating DNS records. 
+node-named provides helper functions for creating DNS records.
 The records are available under 'named.record.NAME' where NAME is one
-of ['A', 'AAAA', 'CNAME', 'SOA', 'MX', 'NS', 'TXT, 'SRV']. It is important to 
-remember that these DNS records are not permanently added to the server. 
+of ['A', 'AAAA', 'CNAME', 'PTR', 'SOA', 'MX', 'NS', 'TXT, 'SRV']. It is important to
+remember that these DNS records are not permanently added to the server.
 They only exist for the length of the particular request. After that, they are
 destroyed. This means you have to create your own lookup mechanism.
 ```javascript
 var named = require('node-named');
-    
+
 var soaRecord = new named.SOARecord('example.com', {serial: 201205150000});
 console.log(soaRecord);
 ```
@@ -48,6 +48,7 @@ The following record types are supported
  * A (ipv4)
  * AAAA (ipv6)
  * CNAME (aliases)
+ * PTR (reverse lookups)
  * SOA (start of authority)
  * MX (mail server records)
  * NS (nameserver entries)
@@ -84,5 +85,5 @@ basis).
 
 ## Looking up Records
 
-There are a few handy ways to lookup DNS records in node. 
+There are a few handy ways to lookup DNS records in node.
 https://github.com/LCMApps/dns-lookup-cache

docs/index.md

@@ -243,6 +243,11 @@ Create an IPv6 resource record.
 Create an Alias record. When these records are sent to the client, the client
 will often make an additional request for the alias itself.
 
+### named.PTRRecord(target)
+
+Create an Alias record. When these records are sent to the client, the client
+will often make an additional request for the alias itself.
+
 ### named.MXRecord(exchange, options)
 
 Create a Mail Server record. A client making this request will often make an

examples/reflect.js

@@ -22,6 +22,10 @@ server.on('query', function(query) {
                 var record = new named.CNAMERecord('cname.example.com');
                 query.addAnswer(domain, record, 300);
                 break;
+        case 'PTR':
+                var record = new named.PTRRecord('ptr.example.com');
+                query.addAnswer(domain, record, 300);
+                break;
         case 'MX':
                 var record = new named.MXRecord('smtp.example.com');
                 query.addAnswer(domain, record, 300);

lib/index.js

@@ -62,16 +62,3 @@ fs.readdirSync(subdir).forEach(function (f) {
                 module.exports[k] = require(path.join(subdir, f));
         }
 });
-// [
-//         'A',
-//         'MX',
-//         'SOA',
-//         'SRV',
-//         'TXT',
-//         'AAAA',
-//         'CNAME'
-// ].forEach(function (r) {
-//         var lcr = r.toLowerCase();
-//         var k = lcr.charAt(0).toUpperCase() + lcr.slice(1) + 'Record';
-//         module.exports[k] = require(path.join(__dirname, 'records/' + lcr))[r];
-// });

lib/protocol.js

@@ -290,6 +290,9 @@ var serializers = {
                         case queryTypes['CNAME']:
                                 r = serializers['_nsName'].encoder(v.target);
                                 break;
+                        case queryTypes['PTR']:
+                                r = serializers['_nsName'].encoder(v.target);
+                                break;
                         case queryTypes['NS']:
                                 r = serializers['_nsName'].encoder(v.target);
                                 break;

lib/query.js

@@ -72,8 +72,10 @@ Query.prototype.encode = function encode() {
                         flags: this._flags,
                         qdCount: this._qdCount,
                         anCount: this._anCount,
-                        nsCount: this._nsCount,
-                        srCount: this._srCount
+                        // nsCount: this._nsCount,
+                        // srCount: this._srCount
+                        nsCount: this._authority ? this._authority.length : 0,
+                        srCount: this._additional ? this._additional.length : 0
                 },
                 question: this._question,
                 answers: this._answers,

lib/records/ptr.js

@@ -0,0 +1,21 @@
+var validators = require('../validators');
+
+
+
+function PTR(target) {
+        if (typeof(target) !== 'string')
+                throw new TypeError('target (string) is required');
+
+        this.target = target;
+        this._type = 'PTR';
+}
+module.exports = PTR;
+
+
+PTR.prototype.valid = function valid() {
+        var self = this, model = {};
+        model = {
+                target: validators.nsName
+        };
+        return validators.validate(self, model);
+};

lib/server.js

@@ -1,5 +1,6 @@
 var assert = require('assert');
 var dgram = require('dgram');
+var net = require('net');
 var EventEmitter = require('events').EventEmitter;
 var util = require('util');
 
@@ -47,10 +48,17 @@ Server.prototype.listen = function listen(port, address, callback) {
                 callback = address;
                 address = '0.0.0.0';
         }
+
+        var address_type = net.isIP(address);
+
+        if(!address_type)
+                throw new TypeError('ip address is invalid');
+
+        var socket_type = address_type == 4 ? 'udp4' : 'udp6'
 
         var self = this;
 
-        this._socket = dgram.createSocket('udp6');
+        this._socket = dgram.createSocket(socket_type);
         this._socket.once('listening', function () {
                 self.emit('listening');
                 if (typeof (callback) === 'function')
@@ -71,7 +79,7 @@ Server.prototype.listen = function listen(port, address, callback) {
                 };
 
                 var src = {
-                        family: 'udp6',
+                        family: socket_type,
                         address: rinfo.address,
                         port: rinfo.port
                 };

test/named.test.js

@@ -41,6 +41,10 @@ before(function (callback) {
                         var record = new named.CNAMERecord('cname.example.com');
                         query.addAnswer(domain, record);
                         break;
+                case 'PTR':
+                        var record = new named.PTRRecord('ptr.example.com');
+                        query.addAnswer(domain, record);
+                        break;
                 case 'NS':
                         var record = new named.NSRecord('ns.example.com');
                         query.addAnswer(domain, record);
@@ -140,6 +144,19 @@ test('answer query: example.com (CNAME)', function (t) {
         });
 });
 
+test('answer query: example.com (PTR)', function (t) {
+        dig('example.com', 'PTR', options, function (err, results) {
+                t.ifError(err);
+                t.deepEqual(results.answers, [{
+                        name: 'example.com.',
+                        ttl: 5,
+                        type: 'PTR',
+                        target: 'ptr.example.com.'
+                }]);
+                t.end();
+        });
+});
+
 test('answer query: example.com (NS)', function (t) {
         dig('example.com', 'NS', options, function (err, results) {
                 t.ifError(err);

test/records.test.js

@@ -35,6 +35,11 @@ test('create a valid record (CNAME)', function(t) {
         testRecord(record, t);
 });
 
+test('create a valid record (PTR)', function(t) {
+        var record = new named.PTRRecord('ptr.example.com');
+        testRecord(record, t);
+});
+
 test('create a valid record (NS)', function(t) {
         var record = new named.NSRecord('ns.example.com');
         testRecord(record, t);