"""
 $Id: win32dns.py,v 1.3.2.1 2007/05/22 20:26:49 customdesigned Exp $

 Extract a list of TCP/IP name servers from the registry 0.1
    0.1 Strobl 2001-07-19
 Usage:
    RegistryResolve() returns a list of ip numbers (dotted quads), by
    scouring the registry for addresses of name servers

 Tested on Windows NT4 Server SP6a, Windows 2000 Pro SP2 and
 Whistler Pro (XP) Build 2462 and Windows ME
 ... all having a different registry layout wrt name servers :-/

 Todo:

   Program doesn't check whether an interface is up or down

 (c) 2001 Copyright by Wolfgang Strobl ws@mystrobl.de,
          License analog to the current Python license
"""

import winreg

def binipdisplay(s):
    "convert a binary array of ip adresses to a python list"
    if len(s) % 4 != 0:
        raise EnvironmentError  # well ...
    ol = []
    s = '.'
    for i in range(int(len(s) / 4)):
        s1 = s[:4]
        s = s[4:]
        ip = []
        for j in s1:
            ip.append(str(ord(j)))
        ol.append(s.join(ip))
    return ol


def stringdisplay(s):
    '''convert "d.d.d.d,d.d.d.d" to ["d.d.d.d","d.d.d.d"].
       also handle u'd.d.d.d d.d.d.d', as reporting on SF
    '''
    import re
    return map(str, re.split("[ ,]", s))


def RegistryResolve():
    nameservers = []
    x = winreg.ConnectRegistry(None, winreg.HKEY_LOCAL_MACHINE)
    try:
        y = winreg.OpenKey(x,
                            r"SYSTEM\CurrentControlSet\Services\Tcpip\Parameters")
    except EnvironmentError:  # so it isn't NT/2000/XP
        # windows ME, perhaps?
        try:  # for Windows ME
            y = winreg.OpenKey(x,
                                r"SYSTEM\CurrentControlSet\Services\VxD\MSTCP")
            nameserver, dummytype = winreg.QueryValueEx(y, 'NameServer')
            if nameserver and not (nameserver in nameservers):
                nameservers.extend(stringdisplay(nameserver))
        except EnvironmentError:
            pass
        return nameservers  # no idea
    try:
        nameserver = winreg.QueryValueEx(y, "DhcpNameServer")[0].split()
    except:
        nameserver = winreg.QueryValueEx(y, "NameServer")[0].split()
    if nameserver:
        nameservers = nameserver
    nameserver = winreg.QueryValueEx(y, "NameServer")[0]
    winreg.CloseKey(y)
    try:  # for win2000
        y = winreg.OpenKey(x,
                            r"SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\DNSRegisteredAdapters")
        for i in range(1000):
            try:
                n = winreg.EnumKey(y, i)
                z = winreg.OpenKey(y, n)
                dnscount, dnscounttype = winreg.QueryValueEx(z,
                                                              'DNSServerAddressCount')
                dnsvalues, dnsvaluestype = winreg.QueryValueEx(z,
                                                                'DNSServerAddresses')
                nameservers.extend(binipdisplay(dnsvalues))
                winreg.CloseKey(z)
            except EnvironmentError:
                break
        winreg.CloseKey(y)
    except EnvironmentError:
        pass
#
    try:  # for whistler
        y = winreg.OpenKey(x,
                            r"SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces")
        for i in range(1000):
            try:
                n = winreg.EnumKey(y, i)
                z = winreg.OpenKey(y, n)
                try:
                    nameserver, dummytype = winreg.QueryValueEx(
                        z, 'NameServer')
                    if nameserver and not (nameserver in nameservers):
                        nameservers.extend(stringdisplay(nameserver))
                except EnvironmentError:
                    pass
                winreg.CloseKey(z)
            except EnvironmentError:
                break
        winreg.CloseKey(y)
    except EnvironmentError:
        # print "Key Interfaces not found, just do nothing."
        pass
#
    winreg.CloseKey(x)
    return nameservers


if __name__ == "__main__":
    print('Name servers:', RegistryResolve())

# $Log: win32dns.py,v $
# Revision 1.3.2.1  2007/05/22 20:26:49  customdesigned
# Fix win32 nameserver discovery.
#
# Revision 1.3  2002/05/06 06:15:31  anthonybaxter
# apparently some versions of windows return servers as unicode
# string with space sep, rather than strings with comma sep.
# *sigh*
#
# Revision 1.2  2002/03/19 12:41:33  anthonybaxter
# tabnannied and reindented everything. 4 space indent, no tabs. yay.
#
# Revision 1.1  2001/08/09 09:22:28  anthonybaxter
# added what I hope is win32 resolver lookup support. I'll need to try
# and figure out how to get the CVS checkout onto my windows machine to
# make sure it works (wow, doing something other than games on the
# windows machine :)
#
# Code from Wolfgang.Strobl@gmd.de
# win32dns.py from
# http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/66260
#
# Really, ParseResolvConf() should be renamed "FindNameServers" or some such.