WIP Packer

README.md

@@ -43,6 +43,7 @@ Similar API to `dns.js` and `native-dns-packet`.
 , "answer": []
 , "authority": []
 , "additional": []
+, "edns_options": []
 , "byteLength": 44
 }
 ```

dns.packer.js

@@ -1,15 +1,21 @@
 (function (exports) {
 'use strict';
 
+var classes = exports.DNS_CLASSES || require('./dns.classes.js').DNS_CLASSES;
+var types = exports.DNS_TYPES || require('./dns.types.js').DNS_TYPES;
+
 var dnspack = exports.DNS_PACKER = {
   pack: function (packet) {
+
+    // TODO update for edns payload size
+    var ab = new ArrayBuffer(576);                  // http://serverfault.com/a/587626/93930
+    var dv = new DataView(ab);
+    var labelsMap = {};
     var total = 0;
     var id = packet.header.id;                      // 2 bytes
     var header = dnspack.packHeader(packet.header); // 2 bytes
     total = 12;                                     // 2+2+2+2 bytes ({qd,an,ns,ar}count)
 
-    var ab = new ArrayBuffer(total);
-    var dv = new DataView(ab);
     dv.setUint16(0, id, false);
     dv.setUint16(2, header, false);
     dv.setUint16(4, packet.question.length, false);
@@ -18,8 +24,112 @@ var dnspack = exports.DNS_PACKER = {
     // EDNS is added as an additional with TYPE 41 (OPT, 0x29)
     dv.setUint16(10, packet.additional.length + (packet.payload ? 1 : 0), false);
 
-    return ab;
+    function lint(r) {
+      if (!r.name) {
+        throw new Error("missing name");
       }
+
+      if (!r.class) {
+        if (!r.className) {
+          throw new Error("no className");
+        }
+        r.class = classes[r.className];
+      }
+
+      if (!r.type) {
+        if (!r.typeName) {
+          throw new Error("no typeName");
+        }
+        r.type = types[r.typeName];
+        if (!r.type) {
+          console.warn("ignoring invalid type '" + r.type + "' for '" + r.name + "', ignoring");
+        }
+      }
+    }
+
+    function packLabel(sequence, terminates) {
+      if (terminates) {
+        // we don't want non-terminating rdata cached, just terminating names
+        labelsMap[total] = { total: total, name: sequence };
+        labelsMap[sequence] = labelsMap[total];
+      }
+      sequence.split('.').forEach(function (label) {
+        dv.setUint8(total, label.length, false);
+        total += 1;
+
+        label.split('').forEach(function (ch) {
+          dv.setUint8(total, ch.charCodeAt(0), false);
+          total += 1;
+        });
+      });
+    }
+
+    function packQuestion(q) {
+      lint(q);
+
+      packLabel(q.name);
+      // trailing 0 (null) as label sequence terminator
+      dv.setUint8(total, 0, false);
+      total += 1;
+
+      dv.setUint16(total, q.type, false);
+      dv.setUint16(total + 2, q.class, false);
+      total += 4; // two bytes type two bytes class
+    }
+
+    function packRdata(a) {
+      dv.setUint16(total, 8, false);
+      total += 2;
+      dv.setUint32(total, 0xFFFFFFFF, false)
+      total += 4;
+      dv.setUint32(total, 0xFFFFFFFF, false)
+      total += 4;
+      //throw new Error('not implemented');
+    }
+
+    function packAnswer(a) {
+      packQuestion(a);
+
+      if ('undefined' === typeof a.ttl) {
+        throw new Error("missing ttl");
+      }
+
+      // 32-bit ttl
+      dv.setUint32(total, a.ttl, false);
+      total += 4;
+
+      if (a.rdata) {
+        // 16-bit
+        dv.setUint16(total, a.rdata.byteLength, false);
+        total += 2;
+        (new Uint8Array(a.rdata)).forEach(function (b) {
+          dv.setUint8(total, b, false);
+          total += 1;
+        });
+      } else {
+        packRdata(a);
+      }
+    }
+
+    //console.log(packet);
+    // fixed size, other than labels
+
+    packet.question.forEach(packQuestion);
+    packet.answer.forEach(packAnswer);
+    packet.authority.forEach(packAnswer);
+    packet.additional.forEach(packAnswer);
+
+    // TODO handle compression pointers
+    // TODO handle edns
+
+    return ab.slice(0, total);
+  }
+
+  /*
+, packLabels: function(map, labels) {
+  }
+  */
+
 , packHeader: function(h) {
     var val = 0;
 
@@ -36,6 +146,7 @@ var dnspack = exports.DNS_PACKER = {
 
     return val;
   }
+
 };
 
 }('undefined' !== typeof window ? window : exports));

dns.parser.js

@@ -232,6 +232,7 @@ pdns.unpack = function (ab) {
     packet.authority.push(rec);
   }
 
+  packet.edns_options = [];
   packet.additional = [];
   for (i = 0; i < packet.arcount; i += 1) {
     rec = unpackAnswer(ab, dv, ui8, total);

dns.types.js

@@ -14,6 +14,7 @@ var types = exports.DNS_TYPES = {
 , OPT: 		0x29  //  41
 , ANY: 		0xff  // 255
 };
+
 // and in reverse
 Object.keys(types).forEach(function (key) {
   types[types[key]] = key;

test/packer.js

@@ -32,9 +32,9 @@
       h = '0' + h;
     }
     return h;
-  }).join('').match(/.{1,2}/g).join(' ').match(/.{1,47}/g).map(function (str) {
+  }).join('').match(/.{1,2}/g).join(' ').match(/.{1,48}/g).map(function (str) {
     var lead = bytecount.toString(16);
-    bytecount += 10;
+    bytecount += 16;
 
     while (lead.length < 7) {
       lead = '0' + lead;
@@ -51,10 +51,15 @@
   console.log('DEBUG with hexdump: ');
   console.log('hexdump ' + onefile.replace(/\.[^\.]*$/, '.bin'));
   console.log('');
+  console.log('        0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F');
   console.log(str + '\n' + trail);
   console.log('');
 
-  console.error('test implementation not complete');
+  console.error('');
+  console.error('!!!');
+  console.error('Test implementation not complete.');
+  console.error('!!!');
+  console.error('');
   process.exit(1);
 
 }());