[Dns] Add basic BinaryDumper implementation and test

Author: igorw

BinaryDumper.php

@@ -6,5 +6,54 @@ class BinaryDumper
 {
     public function toBinary(Message $message)
     {
+        $data = '';
+
+        $data .= $this->headerToBinary($message->header);
+        $data .= $this->questionToBinary($message->question);
+
+        return $data;
+    }
+
+    private function headerToBinary(array $header)
+    {
+        $data = '';
+
+        $data .= pack('n', $header['id']);
+
+        $flags = 0x00;
+        $flags = ($flags << 1) | $header['qr'];
+        $flags = ($flags << 4) | $header['opcode'];
+        $flags = ($flags << 1) | $header['aa'];
+        $flags = ($flags << 1) | $header['tc'];
+        $flags = ($flags << 1) | $header['rd'];
+        $flags = ($flags << 1) | $header['ra'];
+        $flags = ($flags << 3) | $header['z'];
+        $flags = ($flags << 4) | $header['rcode'];
+
+        $data .= pack('n', $flags);
+
+        $data .= pack('n', $header['qdCount']);
+        $data .= pack('n', $header['anCount']);
+        $data .= pack('n', $header['nsCount']);
+        $data .= pack('n', $header['arCount']);
+
+        return $data;
+    }
+
+    private function questionToBinary(array $question)
+    {
+        $data = '';
+
+        foreach ($question as $q) {
+            $labels = explode('.', $q['name']);
+            foreach ($labels as $label) {
+                $data .= chr(strlen($label)).$label;
+            }
+            $data .= "\x00";
+
+            $data .= pack('n*', $q['type'], $q['class']);
+        }
+
+        return $data;
     }
 }