From 997bced8e5e1577aff0696f769a58f9e176ea8b3 Mon Sep 17 00:00:00 2001
From: sbosse <sbosse@uni-bremen.de>
Date: Mon, 21 Jul 2025 23:13:56 +0200
Subject: [PATCH] Mon 21 Jul 22:43:21 CEST 2025

---
 js/demo/UDP_Broker.js | 61 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 js/demo/UDP_Broker.js

diff --git a/js/demo/UDP_Broker.js b/js/demo/UDP_Broker.js
new file mode 100644
index 0000000..aab7c65
--- /dev/null
+++ b/js/demo/UDP_Broker.js
@@ -0,0 +1,61 @@
+// UDP Hole Punching; Rendevouz Broker 
+// usage UDP_Broker
+
+var dgram = require('dgram');
+
+var udp = dgram.createSocket('udp4');
+var udp_port = 10001;
+
+var clients = {};
+
+udp.on('listening', function() {
+  var address = udp.address();
+  console.log('# listening [%s:%s]', address.address, address.port);
+});
+
+udp.on('message', function(data, rinfo) {
+  try {
+    data = JSON.parse(data);
+  } catch (e) {
+    return console.log('! Couldn\'t parse data (%s):\n%s', e, data);
+  }
+  if (data.type == 'register') {
+    clients[data.name] = {
+        name: data.name,
+        connections: {
+          local: data.linfo, 
+          public: rinfo
+        }
+    };
+    console.log('# Client registered: P %s@[%s:%s | L %s:%s]', data.name,
+                rinfo.address, rinfo.port, data.linfo.address, data.linfo.port);
+    send(rinfo.address,rinfo.port,{type:'cack',from:'BROKER'});
+  } else if (data.type == 'connect') {
+    var couple = [ clients[data.from], clients[data.to] ] 
+    for (var i=0; i<couple.length; i++) {
+      if (!couple[i]) return console.log('Client unknown!');
+    }
+    
+    for (var i=0; i<couple.length; i++) {
+      send(couple[i].connections.public.address, couple[i].connections.public.port, {
+        type: 'connection',
+        client: couple[(i+1)%couple.length],
+      }); 
+    }
+  }
+});
+
+var send = function(host, port, msg, cb) {
+  var data = new Buffer(JSON.stringify(msg));
+  udp.send(data, 0, data.length, port, host, function(err, bytes) {
+    if (err) {
+      udp.close();
+      console.log('# stopped due to error: %s', err);
+    } else {
+      console.log('# sent '+msg.type+' to '+host+':'+port);
+      if (cb) cb();
+    }
+  });
+}
+
+udp.bind(udp_port);