bug #4 add cp support

pure-parser.js

@@ -42,6 +42,10 @@ pdns.unpackQname = function (ab, ptr, q) {
   , cpcount: 0
   };
 
+  if (q.cpcount > 25) {
+    throw new Error("compression pointer loop detected (over 25 pointers seems like a loop)");
+  }
+
   do {
     label.length = 0;
     len = ui8[total];
@@ -53,6 +57,12 @@ pdns.unpackQname = function (ab, ptr, q) {
       console.log('ptr to', cpptr);
       console.log('label len', cplen);
       console.log('label', Buffer.from(ui8.slice(cpptr + 1, cpptr + 1 + cplen)).toString('ascii'));
+
+      // we're not coming back!
+      ptr = cpptr;
+      q.cpcount += 1;
+      q.byteLength += 2; // cp and len
+      return pdns.unpackQname(ab, ptr, q);
       throw new Error("discovered a compression pointer at byte " + total
         + " pointing to byte " + ui8[total + 1]
         + ", but compression pointer support is not yet implemented"
@@ -127,6 +137,8 @@ pdns.unpack = function (ab) {
     var ototal = total;
     var data = new Uint8Array(ab).slice(total);
     var q = pdns.unpackQname(ab, total);
+    console.log('unpackQuestion:');
+    console.log(q);
     total += q.byteLength;
 
     if (ab.byteLength - total < 4) {
@@ -149,6 +161,8 @@ pdns.unpack = function (ab) {
     var ototal = total;
     var data = new Uint8Array(ab).slice(total);
     var q = pdns.unpackQname(ab, total);
+    console.log('unpackAnswer:');
+    console.log(q);
     total += q.byteLength;