From 5e1fff748e5269c3f468481d15839521dfc9821e Mon Sep 17 00:00:00 2001
From: AJ ONeal <aj@daplie.com>
Date: Wed, 25 Jan 2017 14:41:30 -0700
Subject: [PATCH] cp ptr updates

---
 bin/dns-parse.js |  1 +
 pure-parser.js   | 43 ++++++++++++++++++++++++++++---------------
 2 files changed, 29 insertions(+), 15 deletions(-)

diff --git a/bin/dns-parse.js b/bin/dns-parse.js
index 0de8c38..cf138db 100644
--- a/bin/dns-parse.js
+++ b/bin/dns-parse.js
@@ -39,6 +39,7 @@ fs.readFileAsync(filename, null).then(function (nb) {
     try {
       record.data = pdns.unpackRdata(nb.buffer, packet, record);
     } catch (e) {
+      console.error(e.stack);
       record.error = e;
     }
   }
diff --git a/pure-parser.js b/pure-parser.js
index 827502b..59f6415 100644
--- a/pure-parser.js
+++ b/pure-parser.js
@@ -26,21 +26,33 @@ pdns.unpackHeader = function (i) {
   return header;
 };
 
-pdns.unpackQname = function (ui8) {
-  var total = 0;
+pdns.unpackQname = function (ab, ptr, q) {
+  var ui8 = new Uint8Array(ab);
+  var total = ptr;
   var i;
 
   var len;
-  var q = {
+  var label = [];
+  q = q || {
     name: ''
   , type: 0
   , class: 0
+  , byteLength: 0
+  , labels: []
+  , cpcount: 0
   };
-  var str = [];
 
   do {
+    label.length = 0;
     len = ui8[total];
     if (0xc0 === len) {
+      console.log('byteLength', ui8.byteLength);
+      var cpptr = ui8[total + 1];
+      var cplen = ui8[ui8[total + 1]];
+      console.log('cp at', total);
+      console.log('ptr to', cpptr);
+      console.log('label len', cplen);
+      console.log('label', Buffer.from(ui8.slice(cpptr + 1, cpptr + 1 + cplen)).toString('ascii'));
       throw new Error("discovered a compression pointer at byte " + total
         + " pointing to byte " + ui8[total + 1]
         + ", but compression pointer support is not yet implemented"
@@ -56,19 +68,21 @@ pdns.unpackQname = function (ui8) {
     for (i = 0; i < len; i += 1) {
       total += 1;
       // TODO check url-allowable characters
-      str.push(String.fromCharCode(ui8[total]));
+      label.push(String.fromCharCode(ui8[total]));
+    }
+    if (label.length) {
+      q.labels.push(label.join(''));
     }
     total += 1;
-    if (ui8[total]) {
-      // pushd connecting '.', but not trailing
-      str.push('.');
-    }
     //console.log('total', total, ui8[total], String.fromCharCode(ui8[total]));
   } while (len);
 
   //str.pop(); // remove trailing '.'
 
-  q.name = str.join('');
+  q.name = q.labels.join('.');
+  if (0 === q.cpcount) {
+    q.byteLength = total - ptr;
+  }
 
   return q;
 };
@@ -112,9 +126,8 @@ pdns.unpack = function (ab) {
   function unpackQuestion(ab, dv, total) {
     var ototal = total;
     var data = new Uint8Array(ab).slice(total);
-    var q = pdns.unpackQname(data);
-    total += q.name.length + 2; // account for leading and trailing string length byte
-
+    var q = pdns.unpackQname(ab, total);
+    total += q.byteLength;
 
     if (ab.byteLength - total < 4) {
       // console.error(str.join(''));
@@ -135,8 +148,8 @@ pdns.unpack = function (ab) {
   function unpackAnswer(ab, dv, total) {
     var ototal = total;
     var data = new Uint8Array(ab).slice(total);
-    var q = pdns.unpackQname(data);
-    total += q.name.length + 2; // account for leading and trailing string length byte
+    var q = pdns.unpackQname(ab, total);
+    total += q.byteLength;
 
 
     if (ab.byteLength - total < 10) {