udpapp.js

var dgram = require('dgram');
var srp = require('srp');
var util = require('util');

var DBConn = require('./dbconn');
var proto = require('./proto');

// UDPApp
//
// This object encompasses all functionality dealing with the UDP endpoint of
// charon.  More specifically, the socket server lives here.

// Constructor
var UDPApp = function(config) {
	"use strict";

	if (!("dbfilename" in config)) {
		throw Error("Missing dbfilename in UDPApp configuration.");
	}
	if (!("port" in config)) {
		throw Error("Missing port in UDPApp configuration.");
	}

	// Create database connection
	this.dbconn = new DBConn({
		filename: config.dbfilename
	});

	// Create socket server
	this.socket = dgram.createSocket('udp4');
	this.socket.on('message', this.router());
	this.socket.bind(config.port);
};

// Object methods
UDPApp.prototype = {
	router: function () {
		var routes = this.routes;
		return function(msg, rinfo) {
			if (msg.length < 4) {
				util.log("Message from " + rinfo.address + " is too small, discarding.");
				return;
			}

			var packetType = msg.readUInt32LE(0);
			if (packetType in routes) {
				router[packetType](msg, rinfo);
			} else {
				util.log("Message from " + rinfo.address + " has an invalid packet type, discarding.");
			}
		}
	}

// Routes
UDPApp.prototype.routes = {};
UDPApp.prototype.routes[proto.SERVER_NEGOTIATE] = function(msg, rinfo) {
	util.log("SERVER_NEGOTIATE not implemented.");
};
UDPApp.prototype.routes[proto.SRP_A] = function(msg, rinfo) {
	util.log("SRP_A not implemented.");
};
UDPApp.prototype.routes[proto.SRP_M] = function(msg, rinfo) {
	util.log("SRP_M not implemented.");
};

module.exports = UDPApp;