SIP Redirect server using node.js

[akh...@braddockinfotech.com]

/* include lib */

var dgram = require('dgram');

var server = dgram.createSocket('udp4');

/* server config */

var host = '192.168.0.177';

var port = 5060;

/* sample INVITE request */

var invite = "INVITE sip:+17066450067@192.168.0.177:5060;transport=udp SIP/2.0\r\nVia: SIP/2.0/UDP 192.168.2.40:5060;rport;branch=z9hG4bK-9a623a408\r\nAllow-Events: message-summary, refer, dialog, line-seize, presence, call-info, as-feature-event\r\nMax-Forwards: 70\r\nCall-ID: C7A7...@192.168.2.40\r\nFrom: <sip:+17066458010@192.168.2.40:5060;otg=16>;tag=192.168.2.40+1+111906+b5b34931\r\nTo: <sip:+17066...@192.168.0.177>\r\nCSeq: 847215118 INVITE\r\nExpires: 180\r\nOrganization: MetaSwitch\r\nSupported: resource-priority, 100rel\r\nContent-Length: 166\r\nContent-Type: application/sdp\r\nAllow: INVITE, ACK, CANCEL, BYE, REGISTER, OPTIONS, PRACK, UPDATE, SUBSCRIBE, NOTIFY, REFER, INFO, PUBLISH\r\nContact: <sip:+17066...@192.168.2.40:5060>\r\nP-Asserted-Identity: <sip:+17066...@192.168.2.40:5060>\r\n\r\nv=0\r\no=- 2012157880 2012157880 IN IP4 192.168.2.14\r\ns=-\r\nc=IN IP4 192.168.2.14\r\nt=0\r\nm=audio 33238 RTP/AVP 18 0 101\r\na=rtpmap:101 telephone-event/8000\r\na=ptime:20";

/* isInvite */

function isInvite(message){

request = message.split('\r\n'); 

pattern = new RegExp(/INVITE/);

request = request[0].match(pattern);

if(request != null){

if(request[0] == "INVITE"){return true;}

else{return false;}

}

}

/* getVia */

function getVia(message){

pattern = new RegExp(/Via:(.*)/);

via = message.match(pattern);

return via[0];

}

/* getFrom */

function getFrom(message){

pattern = new RegExp(/From:(.*)/);

from = message.match(pattern);

return from[0];

}

/* getTo */

function getTo(message){

pattern = new RegExp(/To:(.*)/);

to = message.match(pattern);

return to[0];

}

/* getToNo */

function getToNo(message){

pattern = new RegExp(/To: <sip:(.*)@(.*)>/);

toNo = message.match(pattern);

return toNo[1];

}

/* getCallId */

function getCallId(message){

pattern = new RegExp(/Call-ID:(.*)/);

callId = message.match(pattern);

return callId[0];

}

/* getCseq */

function getCseq(message){

pattern = new RegExp(/CSeq: (.*) INVITE/);

cseq = message.match(pattern);

cseq[1]++;

return cseq[1];

}

/* getIncomingTrunk */

function getIncomingTrunk(message){

pattern = new RegExp(/From: <sip:(.*);otg=(.*)>/);

trunk = message.match(pattern);

return trunk[2];

}

/* getLcrContacts */

function getLcrContacts(message){

var toNo = getToNo(message);

trunks = ["055", "054", "016"];

contacts = [];

for(i = 0; i < trunks.length; i++){

contact = "Contact: <sip:" + toNo + "@" + host + ";dtg=" + trunks[i] + ">";

contacts.push(contact);

}

return contacts.join("\r\n");

}

/* getResponse */

function getResponse(message){

response = "";

response += "SIP/2.0 302 Redirect Request";

response += "\r\n";

response += getVia(message);

response += "\r\n";

response += getFrom(message);

response += "\r\n";

response += getTo(message);

response += "\r\n";

response += getCallId(message);

response += "\r\n";

response += "CSeq: " + getCseq(message) + " INVITE";

response += "\r\n";

response += getLcrContacts(message);

response += "\r\n";

response += "Content-Length: 0";

response += "\r\n";

response += "\r\n";

return response;

}

/*

if(isInvite(invite)){

console.log(getResponse(invite));

};

*/

/* bind to port */

server.bind(port, host);

/* event - start listening */ 

server.on('listening', function () {

    var address = server.address();

    console.log('SIP proxy Server listening on ' + address.address + ':' + address.port + '\n');

});

/* event - on getting message in socket */

server.on('message', function (message) {

message = message.toString();

if(isInvite(message)){

/* convert message object to string */

message = message.toString();

/* log message */

console.log(message);

/* prepare response message */

response = getResponse(message);

/* log response */

console.log(response);

/* convert response to buffer */

response = new Buffer(response);

/* send response to switch */

server.send(response, 0, response.length, port, host, function(err, bytes){

if(err){

throw err;

server.close();

console.log("Server error");

}

});

}

});

The response is not being sent.... do any one know why...