ndns

ndns -- dns client/server library for nodejs

Synposis

An example DNS server written with node which responds 'Hello World':

var ndns = require('ndns');

ndns.createServer('udp4', function (req, res) {
	    res.setHeader(req.header);
	    res.header.qr = 1;
    res.header.aa = 1;
    res.header.rd = 0;
    res.header.ra = 0;
    res.header.ancount = 0;
    for (var i = 0; i < req.q.length; i++) {
	res.q.add(req.q[i]);
	res.addRR(req.q[i].name, 3600, ndns.ns_t.txt, "hello, world");
	res.header.ancount++;
    }
    res.send();
}).bind(5300);

console.log("Server running at 0.0.0.0:5300")

To run the server, put the code into a file called example.js and execute it with the node program:

\> node example.js
Server running at 0.0.0.0:5300

All of the examples in the documentation can be run similarly.

ndns

To use the ndns server and client one must require('ndns').

DNS request messages are represented by an object like this:

{ header:
  { id: 39545
    , qr: 0
    , opcode: 0
    , aa: 0
    , tc: 0
    , rd: 1
    , ra: 0
    , z: 0
    , ad: 0
    , cd: 0
    , rcode: 0
    , qdcount: 1
    , ancount: 0
    , nscount: 0
    , arcount: 0
  }
  , q: 
  { '0': 
    { name: 'example.com'
      , type: 1
      , class: 1
    }
    , length: 1
  }
  , rr: 
  { '0': 
    { name: 'example.com'
      , ttl: 3600
      , class: 1
      , type: 1
      , rdata: '127.0.0.1'
    }
    '1': 
    { name: 'example.com'
      , ttl: 3600
      , class: 1
      , type: 1
      , rdata: '127.0.0.2'
    }
    , length: 2
  }
}

ndns.Server

This is a dgram.Socket with the following events:

Event: 'request'

function (request, response) {}

request is an instance of ndns.ServerRequest and response is an instance of ndns.ServerResponse

ndns.createServer(type, requestListener)

Return a new dns server object

The requestListener is a function which is automatially added to the 'request' event.

For documentation on dgram.Socket, see http://nodejs.org/api.html#dgram-267

ndns.ServerRequest

This object is created internally by a DNS-server, not by the user, and passed as the first argument to a 'request' listener

ndns.ServerResponse

This object is created internally by a DNS-server, not by the user. It is passed as the second argument to the 'request' event.

response.setHeader(headers)

Sets the response header to the request.

Example #1: response.setHeader(request.header); response.header.qr = 1; response.header.qa = 1;

Example #2: response.setHeader({ id: 0, qr: 0, rd: 1, qdcount: 1});

Valid keys id, qr, opcode, aa, tc, rd, ra, z, ad, cd, rcode, qdcount, ancount, nscount and arcount.

This method can be called any number of times and must be called before response.send() is called;

response.addQuestion(name, class, type)