added NS record packer.

packer/type.ns.js

@@ -0,0 +1,39 @@
+(function (exports) {
+'use strict';
+
+
+// NS name for the supplied domain. May be label, pointer or any combination
+
+exports.DNS_PACKER_TYPE_NS = function (ab, dv, total, record) {
+  if(!record.data){
+      throw new Error("no data on NS record");
+  }
+  
+
+  var nsLen = 0;
+  var rdLenIndex = total;
+  total +=2;
+
+  // RDATA 
+  // a sequence of labels
+
+  record.data.split('.').forEach(function(label) {
+      nsLen += 1 + label.length;
+      
+      dv.setUint8(total, label.length, false);
+      total += 1;
+
+      label.split('').forEach(function (ch){
+          dv.setUint8(total, ch.charCodeAt(0), false);
+          total += 1;
+      });
+  });
+
+  // RDLENGTH
+  dv.setUint16(rdLenIndex, record.data.length + 1, false);
+
+
+  return total;
+};
+
+}('undefined' !== typeof window ? window : exports));