more minor updates regarding data retrieval through DNS channel

lib/request/dns.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python
+
+"""
+$Id$
+
+Copyright (c) 2006-2012 sqlmap developers (http://www.sqlmap.org/)
+See the file 'doc/COPYING' for copying permission
+"""
+
+import socket
+import threading
+
+class DNSQuery:
+    """
+    Used for making fake DNS resolution responses based on received
+    raw request
+
+    Reference(s):
+        http://code.activestate.com/recipes/491264-mini-fake-dns-server/
+        https://code.google.com/p/marlon-tools/source/browse/tools/dnsproxy/dnsproxy.py
+    """
+
+    def __init__(self, raw):
+        self._raw = raw
+        self._query = ""
+
+        type_ = (ord(raw[2]) >> 3) & 15                 # Opcode bits
+        if type_ == 0:                                  # Standard query
+            i = 12
+            j = ord(raw[i])
+            while j != 0:
+                self._query += raw[i+1:i+j+1] + '.'
+                i = i + j + 1
+                j = ord(raw[i])
+
+    def response(self, resolution):
+        retval = ""
+
+        if self._query:
+            retval += self._raw[:2] + "\x81\x80"
+            retval += self._raw[4:6] + self._raw[4:6] + "\x00\x00\x00\x00"      # Questions and Answers Counts
+            retval += self._raw[12:]                                            # Original Domain Name Question
+            retval += "\xc0\x0c"                                                # Pointer to domain name
+            retval += "\x00\x01\x00\x01\x00\x00\x00\x3c\x00\x04"                # Response type, ttl and resource data length -> 4 bytes
+            retval += "".join(chr(int(_)) for _ in resolution.split('.'))       # 4 bytes of IP
+
+        return retval
+
+class DNSServer:
+    def __init__(self):
+        self._requests = []
+
+    def run(self):
+        def _():
+            s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+            s.bind(("", 53))
+
+            try:
+                while True:
+                    data, addr = s.recvfrom(1024)
+                    _ = DNSQuery(data)
+                    s.sendto(_.response("127.0.0.1"), addr)
+                    self._requests.append(_._query)
+            finally:
+                s.close()
+
+        thread = threading.Thread(target=_)
+        thread.start()