UDP node fixes. Allow fixing of outbound port.

Fixes #178
Also fixed multicast binding to work more correctly.
Note: - if you fix the outbound port it will then be unvailable for input - as we are not setting up a pool.

nodes/core/io/32-udp.html

@@ -30,7 +30,7 @@
     </div>
     <div class="form-row node-input-iface">
         <label for="node-input-iface"><i class="icon-random"></i> Interface</label>
-        <input type="text" id="node-input-iface" placeholder="eth0">
+        <input type="text" id="node-input-iface" placeholder="(optional) ip address of eth0">
     </div>
     <div class="form-row">
         <label for="node-input-datatype"><i class="icon-file"></i> Output</label>
@@ -103,7 +103,7 @@
           <option value="broad">broadcast message</option>
           <option value="multi">multicast message</option>
         </select>
-        to port <input type="text" id="node-input-port" placeholder="Port" style="width: 45px">
+        to port <input type="text" id="node-input-port" placeholder="Port" style="width: 70px">
     </div>
     <div class="form-row node-input-addr">
         <label for="node-input-addr" id="node-input-addr-label"><i class="icon-list"></i> Address</label>
@@ -111,11 +111,15 @@
     </div>
     <div class="form-row node-input-iface">
         <label for="node-input-iface"><i class="icon-random"></i> Interface</label>
-        <input type="text" id="node-input-iface" placeholder="eth0">
+        <input type="text" id="node-input-iface" placeholder="(optional) ip address of eth0">
+    </div>
+    <div class="form-row">
+        <label for="node-input-outport"><i class="icon-random"></i> optional</label>
+        output port <input type="text" id="node-input-outport"  style="width: 70px;" placeholder="not fixed">
     </div>
     <div class="form-row">
         <label>&nbsp;</label>
-        <input type="checkbox" id="node-input-base64" placeholder="base64" style="display: inline-block; width: auto; vertical-align: top;">
+        <input type="checkbox" id="node-input-base64" style="display: inline-block; width: auto; vertical-align: top;">
         <label for="node-input-base64" style="width: 70%;">Decode Base64 encoded payload ?</label>
     </div>
     <div class="form-row">
@@ -160,6 +164,7 @@
             addr: {value:""},
             iface: {value:""},
             port: {value:""},
+            outport: {value:""},
             base64: {value:false,required:true},
             multicast: {value:"false"}
         },

nodes/core/io/32-udp.js

@@ -49,9 +49,15 @@ function UDPin(n) {
         node.log('udp listener at ' + address.address + ":" + address.port);
         if (node.multicast == "true") {
             server.setBroadcast(true);
+            try {
                 server.setMulticastTTL(128);
                 server.addMembership(node.group,node.iface);
                 node.log("udp multicast group "+node.group);
+            } catch (e) {
+                if (e.errno == "EINVAL") { node.error("Bad Multicast Address"); }
+                else if (e.errno == "ENODEV") { node.error("Must be ip address of the required interface"); }
+                else { node.error("Error :"+e.errno); }
+            }
         }
     });
 
@@ -63,7 +69,7 @@ function UDPin(n) {
         catch (err) { console.log(err); }
     });
 
-    server.bind(node.port);
+    server.bind(node.port,node.iface);
 }
 RED.nodes.registerType("udp in",UDPin);
 
@@ -73,6 +79,7 @@ function UDPout(n) {
     RED.nodes.createNode(this,n);
     //this.group = n.group;
     this.port = n.port;
+    this.outport = n.outport||"";
     this.base64 = n.base64;
     this.addr = n.addr;
     this.iface = n.iface || null;
@@ -81,18 +88,28 @@ function UDPout(n) {
 
     var sock = dgram.createSocket('udp4');  // only use ipv4 for now
 
-    if (this.multicast != "false") {
+    if (node.multicast != "false") {
-        sock.bind(node.port, function() {     // have to bind before you can enable broadcast...
+        if (node.outport == "") { node.outport = node.port; }
+        sock.bind(node.outport, function() {    // have to bind before you can enable broadcast...
             sock.setBroadcast(true);            // turn on broadcast
-            if (this.multicast == "multi") {
+            if (node.multicast == "multi") {
+                try {
                     sock.setMulticastTTL(128);
                     sock.addMembership(node.addr,node.iface);   // Add to the multicast group
-                node.log('udp multicast ready : '+node.addr+":"+node.port);
+                    node.log('udp multicast ready : '+node.outport+' -> '+node.addr+":"+node.port);
+                } catch (e) {
+                    if (e.errno == "EINVAL") { node.error("Bad Multicast Address"); }
+                    else if (e.errno == "ENODEV") { node.error("Must be ip address of the required interface"); }
+                    else { node.error("Error :"+e.errno); }
                 }
-            else node.log('udp broadcast ready : '+node.addr+":"+node.port);
+            }
+            else node.log('udp broadcast ready : '+node.outport+' -> '+node.addr+":"+node.port);
         });
     }
-
+    else if (node.outport != "") {
+        sock.bind(node.outport);
+        node.log('udp ready : '+node.outport+' -> '+node.addr+":"+node.port);
+    }
     else node.log('udp ready : '+node.addr+":"+node.port);
 
     node.on("input", function(msg) {