# SECUREAUTH LABS. Copyright 2018 SecureAuth Corporation. All rights reserved.
#
# This software is provided under under a slightly modified version
# of the Apache Software License. See the accompanying LICENSE file
# for more information.
#
# Description: [MS-TDS] & [MC-SQLR] implementation. 
#
# ToDo:
# [ ] Add all the tokens left 
# [ ] parseRow should be rewritten and add support for all the SQL types in a 
#     good way. Right now it just supports a few types.
# [ ] printRows is crappy, just an easy way to print the rows. It should be 
#     rewritten to output like a normal SQL client
#
# Author:
#  Alberto Solino (@agsolino)
#

from __future__ import division
from __future__ import print_function
import struct
import socket
import select
import random
import binascii
import math
import datetime
import string

from impacket import ntlm, uuid, LOG
from impacket.structure import Structure

try:
    from OpenSSL import SSL
except:
    LOG.critical("pyOpenSSL is not installed, can't continue")
    raise

# We need to have a fake Logger to be compatible with the way Impact 
# prints information. Outside Impact it's just a print. Inside 
# we will receive the Impact logger instance to print row information
# The rest it processed through the standard impacket logging mech.
class DummyPrint:        
    def logMessage(self,message):
        if message == '\n':
            print(message)
        else:
            print(message, end=' ')

# MC-SQLR Constants and Structures
SQLR_PORT           = 1434
SQLR_CLNT_BCAST_EX  = 0x02
SQLR_CLNT_UCAST_EX  = 0x03
SQLR_CLNT_UCAST_INST= 0x04
SQLR_CLNT_UCAST_DAC = 0x0f


class SQLR(Structure):
    commonHdr = (
        ('OpCode','B'),
    )

class SQLR_UCAST_INST(SQLR):
    structure = (
        ('Instance',':')
    )
    def __init__(self, data = None):
        SQLR.__init__(self,data)
        if data is not None:
            self['OpCode'] = SQLR_CLNT_UCAST_INST

class SQLR_UCAST_DAC(SQLR):
    structure = (
        ('Protocol', 'B=1'),
        ('Instance', ':'),
    )
    def __init__(self, data = None):
        SQLR.__init__(self,data)
        if data is not None:
            self['OpCode'] = SQLR_CLNT_UCAST_DAC

class SQLR_Response(SQLR):
    structure = (
        ('Size','<H'),
        ('_Data','_-Data','self["Size"]'),
        ('Data',':'),
    )
    
class SQLErrorException(Exception):
    pass

# TDS Constants and Structures

# TYPE constants
TDS_SQL_BATCH       = 1
TDS_PRE_TDS_LOGIN   = 2
TDS_RPC             = 3
TDS_TABULAR         = 4
TDS_ATTENTION       = 6
TDS_BULK_LOAD_DATA  = 7
TDS_TRANSACTION     = 14
TDS_LOGIN7          = 16
TDS_SSPI            = 17
TDS_PRE_LOGIN       = 18

# Status constants
TDS_STATUS_NORMAL            = 0
TDS_STATUS_EOM               = 1 
TDS_STATUS_RESET_CONNECTION  = 8
TDS_STATUS_RESET_SKIPTRANS   = 16

# Encryption
TDS_ENCRYPT_OFF              = 0
TDS_ENCRYPT_ON               = 1
TDS_ENCRYPT_NOT_SUP          = 2
TDS_ENCRYPT_REQ              = 3

# Option 2 Flags
TDS_INTEGRATED_SECURITY_ON   = 0x80
TDS_INIT_LANG_FATAL          = 0x01
TDS_ODBC_ON                  = 0x02

# Token Types
TDS_ALTMETADATA_TOKEN        = 0x88
TDS_ALTROW_TOKEN             = 0xD3
TDS_COLMETADATA_TOKEN        = 0x81
TDS_COLINFO_TOKEN            = 0xA5
TDS_DONE_TOKEN               = 0xFD
TDS_DONEPROC_TOKEN           = 0xFE
TDS_DONEINPROC_TOKEN         = 0xFF
TDS_ENVCHANGE_TOKEN          = 0xE3
TDS_ERROR_TOKEN              = 0xAA
TDS_INFO_TOKEN               = 0xAB
TDS_LOGINACK_TOKEN           = 0xAD
TDS_NBCROW_TOKEN             = 0xD2
TDS_OFFSET_TOKEN             = 0x78
TDS_ORDER_TOKEN              = 0xA9
TDS_RETURNSTATUS_TOKEN       = 0x79
TDS_RETURNVALUE_TOKEN        = 0xAC
TDS_ROW_TOKEN                = 0xD1
TDS_SSPI_TOKEN               = 0xED
TDS_TABNAME_TOKEN            = 0xA4

# ENVCHANGE Types
TDS_ENVCHANGE_DATABASE       = 1
TDS_ENVCHANGE_LANGUAGE       = 2
TDS_ENVCHANGE_CHARSET        = 3
TDS_ENVCHANGE_PACKETSIZE     = 4
TDS_ENVCHANGE_UNICODE        = 5
TDS_ENVCHANGE_UNICODE_DS     = 6
TDS_ENVCHANGE_COLLATION      = 7
TDS_ENVCHANGE_TRANS_START    = 8
TDS_ENVCHANGE_TRANS_COMMIT   = 9
TDS_ENVCHANGE_ROLLBACK       = 10
TDS_ENVCHANGE_DTC            = 11

# Column types
# FIXED-LEN Data Types
TDS_NULL_TYPE                = 0x1F
TDS_INT1TYPE                 = 0x30
TDS_BITTYPE                  = 0x32
TDS_INT2TYPE                 = 0x34
TDS_INT4TYPE                 = 0x38
TDS_DATETIM4TYPE             = 0x3A
TDS_FLT4TYPE                 = 0x3B
TDS_MONEYTYPE                = 0x3C
TDS_DATETIMETYPE             = 0x3D
TDS_FLT8TYPE                 = 0x3E
TDS_MONEY4TYPE               = 0x7A
TDS_INT8TYPE                 = 0x7F

# VARIABLE-Len Data Types
TDS_GUIDTYPE                 = 0x24
TDS_INTNTYPE                 = 0x26
TDS_DECIMALTYPE              = 0x37
TDS_NUMERICTYPE              = 0x3F
TDS_BITNTYPE                 = 0x68
TDS_DECIMALNTYPE             = 0x6A
TDS_NUMERICNTYPE             = 0x6C
TDS_FLTNTYPE                 = 0x6D
TDS_MONEYNTYPE               = 0x6E
TDS_DATETIMNTYPE             = 0x6F
TDS_DATENTYPE                = 0x28
TDS_TIMENTYPE                = 0x29
TDS_DATETIME2NTYPE           = 0x2A
TDS_DATETIMEOFFSETNTYPE      = 0x2B
TDS_CHARTYPE                 = 0x2F
TDS_VARCHARTYPE              = 0x27
TDS_BINARYTYPE               = 0x2D
TDS_VARBINARYTYPE            = 0x25
TDS_BIGVARBINTYPE            = 0xA5
TDS_BIGVARCHRTYPE            = 0xA7
TDS_BIGBINARYTYPE            = 0xAD
TDS_BIGCHARTYPE              = 0xAF
TDS_NVARCHARTYPE             = 0xE7
TDS_NCHARTYPE                = 0xEF
TDS_XMLTYPE                  = 0xF1
TDS_UDTTYPE                  = 0xF0
TDS_TEXTTYPE                 = 0x23
TDS_IMAGETYPE                = 0x22
TDS_NTEXTTYPE                = 0x63
TDS_SSVARIANTTYPE            = 0x62

class TDSPacket(Structure):
    structure = (
        ('Type','<B'),
        ('Status','<B=1'),
        ('Length','>H=8+len(Data)'),
        ('SPID','>H=0'),
        ('PacketID','<B=0'),
        ('Window','<B=0'),
        ('Data',':'),
    )

class TDS_PRELOGIN(Structure):
    structure = (
        ('VersionToken','>B=0'),
        ('VersionOffset','>H'),
        ('VersionLength','>H=len(self["Version"])'),
        ('EncryptionToken','>B=0x1'),
        ('EncryptionOffset','>H'),
        ('EncryptionLength','>H=1'),
        ('InstanceToken','>B=2'),
        ('InstanceOffset','>H'),
        ('InstanceLength','>H=len(self["Instance"])'),
        ('ThreadIDToken','>B=3'),
        ('ThreadIDOffset','>H'),
        ('ThreadIDLength','>H=4'),
        ('EndToken','>B=0xff'),
        ('_Version','_-Version','self["VersionLength"]'),
        ('Version',':'),
        ('Encryption','B'),
        ('_Instance','_-Instance','self["InstanceLength"]-1'),
        ('Instance',':'),
        ('ThreadID',':'),
    )

    def getData(self):
        self['VersionOffset']=21
        self['EncryptionOffset']=self['VersionOffset'] + len(self['Version'])
        self['InstanceOffset']=self['EncryptionOffset'] + 1
        self['ThreadIDOffset']=self['InstanceOffset'] + len(self['Instance'])
        return Structure.getData(self)

class TDS_LOGIN(Structure):
    structure = (
        ('Length','<L=0'),
        ('TDSVersion','>L=0x71'),
        ('PacketSize','<L=32764'),
        ('ClientProgVer','>L=7'),
        ('ClientPID','<L=0'),
        ('ConnectionID','<L=0'),
        ('OptionFlags1','<B=0xe0'),
        ('OptionFlags2','<B'),
        ('TypeFlags','<B=0'),
        ('OptionFlags3','<B=0'),
        ('ClientTimeZone','<L=0'),
        ('ClientLCID','<L=0'),
        ('HostNameOffset','<H'),
        ('HostNameLength','<H=len(self["HostName"])//2'),
        ('UserNameOffset','<H=0'),
        ('UserNameLength','<H=len(self["UserName"])//2'),
        ('PasswordOffset','<H=0'),
        ('PasswordLength','<H=len(self["Password"])//2'),
        ('AppNameOffset','<H'),
        ('AppNameLength','<H=len(self["AppName"])//2'),
        ('ServerNameOffset','<H'),
        ('ServerNameLength','<H=len(self["ServerName"])//2'),
        ('UnusedOffset','<H=0'),
        ('UnusedLength','<H=0'),
        ('CltIntNameOffset','<H'),
        ('CltIntNameLength','<H=len(self["CltIntName"])//2'),
        ('LanguageOffset','<H=0'),
        ('LanguageLength','<H=0'),
        ('DatabaseOffset','<H=0'),
        ('DatabaseLength','<H=len(self["Database"])//2'),
        ('ClientID','6s=b"\x01\x02\x03\x04\x05\x06"'),
        ('SSPIOffset','<H'),
        ('SSPILength','<H=len(self["SSPI"])'),
        ('AtchDBFileOffset','<H'),
        ('AtchDBFileLength','<H=len(self["AtchDBFile"])//2'),
        ('HostName',':'),
        ('UserName',':'),
        ('Password',':'),
        ('AppName',':'),
        ('ServerName',':'),
        ('CltIntName',':'),
        ('Database',':'),
        ('SSPI',':'),
        ('AtchDBFile',':'),
    )
    def __init__(self,data=None):
        Structure.__init__(self,data)
        if data is None:
            self['UserName'] = ''
            self['Password'] = ''
            self['Database'] = ''
            self['AtchDBFile'] = ''

    def fromString(self, data):
        Structure.fromString(self, data)
        if self['HostNameLength'] > 0:
            self['HostName'] = data[self['HostNameOffset']:][:self['HostNameLength']*2]

        if self['UserNameLength'] > 0:
            self['UserName'] = data[self['UserNameOffset']:][:self['UserNameLength']*2]

        if self['PasswordLength'] > 0:
            self['Password'] = data[self['PasswordOffset']:][:self['PasswordLength']*2]

        if self['AppNameLength'] > 0:
            self['AppName'] = data[self['AppNameOffset']:][:self['AppNameLength']*2]

        if self['ServerNameLength'] > 0:
            self['ServerName'] = data[self['ServerNameOffset']:][:self['ServerNameLength']*2]

        if self['CltIntNameLength'] > 0:
            self['CltIntName'] = data[self['CltIntNameOffset']:][:self['CltIntNameLength']*2]

        if self['DatabaseLength'] > 0:
            self['Database'] = data[self['DatabaseOffset']:][:self['DatabaseLength']*2]

        if self['SSPILength'] > 0:
            self['SSPI'] = data[self['SSPIOffset']:][:self['SSPILength']*2]

        if self['AtchDBFileLength'] > 0:
            self['AtchDBFile'] = data[self['AtchDBFileOffset']:][:self['AtchDBFileLength']*2]

    def getData(self):
        index = 36+50
        self['HostNameOffset']= index

        index += len(self['HostName'])

        if self['UserName'] != '':
            self['UserNameOffset'] = index
        else:
            self['UserNameOffset'] = 0

        index += len(self['UserName'])

        if self['Password'] != '':
            self['PasswordOffset'] = index
        else:
            self['PasswordOffset'] = 0

        index += len(self['Password'])

        self['AppNameOffset']= index
        self['ServerNameOffset']=self['AppNameOffset'] + len(self['AppName'])
        self['CltIntNameOffset']=self['ServerNameOffset'] + len(self['ServerName'])
        self['LanguageOffset']=self['CltIntNameOffset'] + len(self['CltIntName'])
        self['DatabaseOffset']=self['LanguageOffset'] 
        self['SSPIOffset']=self['DatabaseOffset'] + len(self['Database'])
        self['AtchDBFileOffset']=self['SSPIOffset'] + len(self['SSPI'])
        return Structure.getData(self)

class TDS_LOGIN_ACK(Structure):
    structure = (
        ('TokenType','<B'),
        ('Length','<H'),
        ('Interface','<B'),
        ('TDSVersion','<L'),
        ('ProgNameLen','<B'),
        ('_ProgNameLen','_-ProgName','self["ProgNameLen"]*2'),
        ('ProgName',':'),
        ('MajorVer','<B'),
        ('MinorVer','<B'),
        ('BuildNumHi','<B'),
        ('BuildNumLow','<B'),
    )

class TDS_RETURNSTATUS(Structure):
    structure = (
        ('TokenType','<B'),
        ('Value','<L'),
    )

class TDS_INFO_ERROR(Structure):
    structure = (
        ('TokenType','<B'),
        ('Length','<H'),
        ('Number','<L'),
        ('State','<B'),
        ('Class','<B'),
        ('MsgTextLen','<H'),
        ('_MsgTextLen','_-MsgText','self["MsgTextLen"]*2'),
        ('MsgText',':'),
        ('ServerNameLen','<B'),
        ('_ServerNameLen','_-ServerName','self["ServerNameLen"]*2'),
        ('ServerName',':'),
        ('ProcNameLen','<B'),
        ('_ProcNameLen','_-ProcName','self["ProcNameLen"]*2'),
        ('ProcName',':'),
        ('LineNumber','<H'),
    )

class TDS_ENVCHANGE(Structure):
    structure = (
        ('TokenType','<B'),
        ('Length','<H=4+len(Data)'),
        ('Type','<B'),
        ('_Data','_-Data','self["Length"]-1'),
        ('Data',':'),
    )

class TDS_DONEINPROC(Structure):
    structure = (
        ('TokenType','<B'),
        ('Status','<H'),
        ('CurCmd','<H'),
        ('DoneRowCount','<L'),
    )

class TDS_ORDER(Structure):
    structure = (
        ('TokenType','<B'),
        ('Length','<H'),
        ('_Data','_-Data','self["Length"]'),
        ('Data',':'),
    )


class TDS_ENVCHANGE_VARCHAR(Structure):
    structure = (
        ('NewValueLen','<B=len(NewValue)'),
        ('_NewValue','_-NewValue','self["NewValueLen"]*2'),
        ('NewValue',':'),
        ('OldValueLen','<B=len(OldValue)'),
        ('_OldValue','_-OldValue','self["OldValueLen"]*2'),
        ('OldValue',':'),
    )
    
class TDS_ROW(Structure):
    structure = (
        ('TokenType','<B'),
        ('Data',':'),
    )

class TDS_DONE(Structure):
    structure = (
        ('TokenType','<B'),
        ('Status','<H'),
        ('CurCmd','<H'),
        ('DoneRowCount','<L'),
    )

class TDS_COLMETADATA(Structure):
    structure = (
        ('TokenType','<B'),
        ('Count','<H'),
        ('Data',':'),
    )

class MSSQL:
    def __init__(self, address, port=1433, rowsPrinter=DummyPrint()):
        #self.packetSize = 32764
        self.packetSize = 32763
        self.server = address
        self.port = port
        self.socket = 0
        self.replies = {}
        self.colMeta = []
        self.rows = []
        self.currentDB = ''
        self.COL_SEPARATOR = '  '
        self.MAX_COL_LEN = 255
        self.lastError = False
        self.tlsSocket = None
        self.__rowsPrinter = rowsPrinter

    def getInstances(self, timeout = 5):
        packet = SQLR()
        packet['OpCode'] = SQLR_CLNT_UCAST_EX

        # Open the connection
        af, socktype, proto, canonname, sa = socket.getaddrinfo(self.server, SQLR_PORT, 0, socket.SOCK_DGRAM)[0]
        s = socket.socket(af, socktype, proto)

        s.sendto(packet.getData(), 0, ( self.server, SQLR_PORT ))
        ready, _, _ = select.select([ s.fileno() ], [ ] , [ ], timeout)
        if not ready:
            return []
        else:
            data, _ = s.recvfrom(65536, 0)
   
        s.close()
        resp = SQLR_Response(data)

        # Now parse the results
        entries = resp['Data'].split(b';;')

        # We don't want the last one, it's empty
        entries.pop()
 
        # the answer to send back
        resp = []

        for i, entry in enumerate(entries):
            fields = entry.split(b';')
            ret = {}
            for j, field in enumerate(fields):
                if (j & 0x1) == 0:
                    ret[field.decode('utf-8')] = fields[j+1].decode('utf-8')
            resp.append(ret)

        return resp
        

    def preLogin(self):
        prelogin = TDS_PRELOGIN()
        prelogin['Version'] = b"\x08\x00\x01\x55\x00\x00"
        #prelogin['Encryption'] = TDS_ENCRYPT_NOT_SUP
        prelogin['Encryption'] = TDS_ENCRYPT_OFF
        prelogin['ThreadID'] = struct.pack('<L',random.randint(0,65535))
        prelogin['Instance'] = b'MSSQLServer\x00'

        self.sendTDS(TDS_PRE_LOGIN, prelogin.getData(), 0)
        tds = self.recvTDS()

        return TDS_PRELOGIN(tds['Data'])
    
    def encryptPassword(self, password ):
        return bytes(bytearray([((x & 0x0f) << 4) + ((x & 0xf0) >> 4) ^ 0xa5 for x in bytearray(password)]))

    def connect(self):
        af, socktype, proto, canonname, sa = socket.getaddrinfo(self.server, self.port, 0, socket.SOCK_STREAM)[0]
        sock = socket.socket(af, socktype, proto)
        
        try:
            sock.connect(sa)
        except Exception:
            #import traceback
            #traceback.print_exc()
            raise
        
        self.socket = sock
        return sock

    def disconnect(self):
        if self.socket:
            return self.socket.close()

    def setPacketSize(self, packetSize):
        self.packetSize = packetSize

    def getPacketSize(self):
        return self.packetSize
    
    def socketSendall(self,data):
        if self.tlsSocket is None:
            return self.socket.sendall(data)
        else:
            self.tlsSocket.sendall(data)
            dd = self.tlsSocket.bio_read(self.packetSize)
            return self.socket.sendall(dd)

    def sendTDS(self, packetType, data, packetID = 1):
        if (len(data)-8) > self.packetSize:
            remaining = data[self.packetSize-8:]
            tds = TDSPacket()
            tds['Type'] = packetType
            tds['Status'] = TDS_STATUS_NORMAL
            tds['PacketID'] = packetID
            tds['Data'] = data[:self.packetSize-8]
            self.socketSendall(tds.getData())

            while len(remaining) > (self.packetSize-8):
                packetID += 1
                tds['PacketID'] = packetID
                tds['Data'] = remaining[:self.packetSize-8]
                self.socketSendall(tds.getData())
                remaining = remaining[self.packetSize-8:]
            data = remaining
            packetID+=1

        tds = TDSPacket()
        tds['Type'] = packetType
        tds['Status'] = TDS_STATUS_EOM
        tds['PacketID'] = packetID
        tds['Data'] = data
        self.socketSendall(tds.getData())

    def socketRecv(self, packetSize):
        data = self.socket.recv(packetSize)
        if self.tlsSocket is not None:
            dd = ''
            self.tlsSocket.bio_write(data)
            while True:
                try:
                    dd += self.tlsSocket.read(packetSize)
                except SSL.WantReadError:
                    data2 = self.socket.recv(packetSize - len(data) )
                    self.tlsSocket.bio_write(data2)
                    pass
                else:
                    data = dd
                    break
        return data

    def recvTDS(self, packetSize = None):
        # Do reassembly here
        if packetSize is None:
            packetSize = self.packetSize
        packet = TDSPacket(self.socketRecv(packetSize))
        status = packet['Status']
        packetLen = packet['Length']-8
        while packetLen > len(packet['Data']):
            data = self.socketRecv(packetSize)
            packet['Data'] += data
        
        remaining = None
        if packetLen <  len(packet['Data']):
            remaining = packet['Data'][packetLen:]
            packet['Data'] = packet['Data'][:packetLen]

        #print "REMAINING ", 
        #if remaining is None: 
        #   print None 
        #else: 
        #   print len(remaining)

        while status != TDS_STATUS_EOM:
            if remaining is not None:
                tmpPacket = TDSPacket(remaining)
            else:
                tmpPacket = TDSPacket(self.socketRecv(packetSize))

            packetLen = tmpPacket['Length'] - 8
            while packetLen > len(tmpPacket['Data']):
                data = self.socketRecv(packetSize)
                tmpPacket['Data'] += data

            remaining = None
            if packetLen <  len(tmpPacket['Data']):
                remaining = tmpPacket['Data'][packetLen:]
                tmpPacket['Data'] = tmpPacket['Data'][:packetLen]

            status = tmpPacket['Status']
            packet['Data'] += tmpPacket['Data']
            packet['Length'] += tmpPacket['Length'] - 8
            
        #print packet['Length']
        return packet

    def kerberosLogin(self, database, username, password='', domain='', hashes=None, aesKey='', kdcHost=None, TGT=None, TGS=None, useCache=True):

        if hashes is not None:
            lmhash, nthash = hashes.split(':')
            lmhash = binascii.a2b_hex(lmhash)
            nthash = binascii.a2b_hex(nthash)
        else:
            lmhash = ''
            nthash = ''

        resp = self.preLogin()
        # Test this!
        if resp['Encryption'] == TDS_ENCRYPT_REQ or resp['Encryption'] == TDS_ENCRYPT_OFF:
            LOG.info("Encryption required, switching to TLS")

            # Switching to TLS now
            ctx = SSL.Context(SSL.TLSv1_METHOD)
            ctx.set_cipher_list('RC4, AES256')
            tls = SSL.Connection(ctx,None)
            tls.set_connect_state()
            while True:
                try:
                    tls.do_handshake()
                except SSL.WantReadError:
                    data = tls.bio_read(4096)
                    self.sendTDS(TDS_PRE_LOGIN, data,0)
                    tds = self.recvTDS()
                    tls.bio_write(tds['Data'])
                else:
                    break

            # SSL and TLS limitation: Secure Socket Layer (SSL) and its replacement,
            # Transport Layer Security(TLS), limit data fragments to 16k in size.
            self.packetSize = 16*1024-1
            self.tlsSocket = tls


        login = TDS_LOGIN()

        login['HostName'] = (''.join([random.choice(string.ascii_letters) for _ in range(8)])).encode('utf-16le')
        login['AppName']  = (''.join([random.choice(string.ascii_letters) for _ in range(8)])).encode('utf-16le')
        login['ServerName'] = self.server.encode('utf-16le')
        login['CltIntName']  = login['AppName']
        login['ClientPID'] = random.randint(0,1024)
        login['PacketSize'] = self.packetSize
        if database is not None:
            login['Database'] = database.encode('utf-16le')
        login['OptionFlags2'] = TDS_INIT_LANG_FATAL | TDS_ODBC_ON

        from impacket.spnego import SPNEGO_NegTokenInit, TypesMech
        # Importing down here so pyasn1 is not required if kerberos is not used.
        from impacket.krb5.asn1 import AP_REQ, Authenticator, TGS_REP, seq_set
        from impacket.krb5.kerberosv5 import getKerberosTGT, getKerberosTGS, KerberosError
        from impacket.krb5 import constants
        from impacket.krb5.types import Principal, KerberosTime, Ticket
        from pyasn1.codec.der import decoder, encoder
        from pyasn1.type.univ import noValue
        from impacket.krb5.ccache import CCache
        import os
        import datetime

        if useCache is True:
            try:
                ccache = CCache.loadFile(os.getenv('KRB5CCNAME'))
            except:
                # No cache present
                pass
            else:
                # retrieve domain information from CCache file if needed
                if domain == '':
                    domain = ccache.principal.realm['data'].decode('utf-8')
                    LOG.debug('Domain retrieved from CCache: %s' % domain)

                LOG.debug("Using Kerberos Cache: %s" % os.getenv('KRB5CCNAME'))
                principal = 'MSSQLSvc/%s.%s:%d@%s' % (self.server.split('.')[0], domain, self.port, domain.upper())
                creds = ccache.getCredential(principal)

                if creds is not None:
                    TGS = creds.toTGS(principal)
                    LOG.debug('Using TGS from cache')
                else:
                    # search for the port's instance name instead (instance name based SPN)
                    LOG.debug('Searching target\'s instances to look for port number %s' % self.port)
                    instances = self.getInstances()
                    instanceName = None
                    for i in instances:
                        try:
                            if int(i['tcp']) == self.port:
                                instanceName = i['InstanceName']
                        except:
                            pass

                    if instanceName:
                        principal = 'MSSQLSvc/%s.%s:%s@%s' % (self.server, domain, instanceName, domain.upper())
                        creds = ccache.getCredential(principal)

                    if creds is not None:
                        TGS = creds.toTGS(principal)
                        LOG.debug('Using TGS from cache')
                    else:
                        # Let's try for the TGT and go from there
                        principal = 'krbtgt/%s@%s' % (domain.upper(),domain.upper())
                        creds =  ccache.getCredential(principal)
                        if creds is not None:
                            TGT = creds.toTGT()
                            LOG.debug('Using TGT from cache')
                        else:
                            LOG.debug("No valid credentials found in cache. ")

                # retrieve user information from CCache file if needed
                if username == '' and creds is not None:
                    username = creds['client'].prettyPrint().split(b'@')[0].decode('utf-8')
                    LOG.debug('Username retrieved from CCache: %s' % username)
                elif username == '' and len(ccache.principal.components) > 0:
                    username = ccache.principal.components[0]['data'].decode('utf-8')
                    LOG.debug('Username retrieved from CCache: %s' % username)

        # First of all, we need to get a TGT for the user
        userName = Principal(username, type=constants.PrincipalNameType.NT_PRINCIPAL.value)
        while True:
            if TGT is None:
                if TGS is None:
                    try:
                        tgt, cipher, oldSessionKey, sessionKey = getKerberosTGT(userName, password, domain, lmhash, nthash, aesKey, kdcHost)
                    except KerberosError as e:
                        if e.getErrorCode() == constants.ErrorCodes.KDC_ERR_ETYPE_NOSUPP.value:
                            # We might face this if the target does not support AES
                            # So, if that's the case we'll force using RC4 by converting
                            # the password to lm/nt hashes and hope for the best. If that's already
                            # done, byebye.
                            if lmhash == '' and nthash == '' and (aesKey == '' or aesKey is None) and TGT is None and TGS is None:
                                from impacket.ntlm import compute_lmhash, compute_nthash
                                LOG.debug('Got KDC_ERR_ETYPE_NOSUPP, fallback to RC4')
                                lmhash = compute_lmhash(password)
                                nthash = compute_nthash(password)
                                continue
                            else:
                                raise
                        else:
                            raise
            else:
                tgt = TGT['KDC_REP']
                cipher = TGT['cipher']
                sessionKey = TGT['sessionKey']

            if TGS is None:
                # From https://msdn.microsoft.com/en-us/library/ms191153.aspx?f=255&MSPPError=-2147217396
                # Beginning with SQL Server 2008, the SPN format is changed in order to support Kerberos authentication
                # on TCP/IP, named pipes, and shared memory. The supported SPN formats for named and default instances
                # are as follows.
                # Named instance
                #     MSSQLSvc/FQDN:[port | instancename], where:
                #         MSSQLSvc is the service that is being registered.
                #         FQDN is the fully qualified domain name of the server.
                #         port is the TCP port number.
                #         instancename is the name of the SQL Server instance.
                serverName = Principal('MSSQLSvc/%s.%s:%d' % (self.server.split('.')[0], domain, self.port), type=constants.PrincipalNameType.NT_SRV_INST.value)
                try:
                    tgs, cipher, oldSessionKey, sessionKey = getKerberosTGS(serverName, domain, kdcHost, tgt, cipher, sessionKey)
                except KerberosError as e:
                    if e.getErrorCode() == constants.ErrorCodes.KDC_ERR_ETYPE_NOSUPP.value:
                        # We might face this if the target does not support AES
                        # So, if that's the case we'll force using RC4 by converting
                        # the password to lm/nt hashes and hope for the best. If that's already
                        # done, byebye.
                        if lmhash == '' and nthash == '' and (aesKey == '' or aesKey is None) and TGT is None and TGS is None:
                            from impacket.ntlm import compute_lmhash, compute_nthash
                            LOG.debug('Got KDC_ERR_ETYPE_NOSUPP, fallback to RC4')
                            lmhash = compute_lmhash(password)
                            nthash = compute_nthash(password)
                        else:
                            raise
                    else:
                        raise
                else:
                    break
            else:
                tgs = TGS['KDC_REP']
                cipher = TGS['cipher']
                sessionKey = TGS['sessionKey']
                break

        # Let's build a NegTokenInit with a Kerberos REQ_AP

        blob = SPNEGO_NegTokenInit()

        # Kerberos
        blob['MechTypes'] = [TypesMech['MS KRB5 - Microsoft Kerberos 5']]

        # Let's extract the ticket from the TGS
        tgs = decoder.decode(tgs, asn1Spec = TGS_REP())[0]
        ticket = Ticket()
        ticket.from_asn1(tgs['ticket'])

        # Now let's build the AP_REQ
        apReq = AP_REQ()
        apReq['pvno'] = 5
        apReq['msg-type'] = int(constants.ApplicationTagNumbers.AP_REQ.value)

        opts = list()
        apReq['ap-options'] = constants.encodeFlags(opts)
        seq_set(apReq,'ticket', ticket.to_asn1)

        authenticator = Authenticator()
        authenticator['authenticator-vno'] = 5
        authenticator['crealm'] = domain
        seq_set(authenticator, 'cname', userName.components_to_asn1)
        now = datetime.datetime.utcnow()

        authenticator['cusec'] = now.microsecond
        authenticator['ctime'] = KerberosTime.to_asn1(now)

        encodedAuthenticator = encoder.encode(authenticator)

        # Key Usage 11
        # AP-REQ Authenticator (includes application authenticator
        # subkey), encrypted with the application session key
        # (Section 5.5.1)
        encryptedEncodedAuthenticator = cipher.encrypt(sessionKey, 11, encodedAuthenticator, None)

        apReq['authenticator'] = noValue
        apReq['authenticator']['etype'] = cipher.enctype
        apReq['authenticator']['cipher'] = encryptedEncodedAuthenticator

        blob['MechToken'] = encoder.encode(apReq)

        login['OptionFlags2'] |= TDS_INTEGRATED_SECURITY_ON

        login['SSPI'] = blob.getData()
        login['Length'] = len(login.getData())

        # Send the NTLMSSP Negotiate or SQL Auth Packet
        self.sendTDS(TDS_LOGIN7, login.getData())

        # According to the specs, if encryption is not required, we must encrypt just
        # the first Login packet :-o
        if resp['Encryption'] == TDS_ENCRYPT_OFF:
            self.tlsSocket = None

        tds = self.recvTDS()

        self.replies = self.parseReply(tds['Data'])

        if TDS_LOGINACK_TOKEN in self.replies:
            return True
        else:
            return False

    def login(self, database, username, password='', domain='', hashes = None, useWindowsAuth = False):

        if hashes is not None:
            lmhash, nthash = hashes.split(':')
            lmhash = binascii.a2b_hex(lmhash)
            nthash = binascii.a2b_hex(nthash)
        else:
            lmhash = ''
            nthash = ''

        resp = self.preLogin()
        # Test this!
        if resp['Encryption'] == TDS_ENCRYPT_REQ or resp['Encryption'] == TDS_ENCRYPT_OFF:
            LOG.info("Encryption required, switching to TLS")

            # Switching to TLS now
            ctx = SSL.Context(SSL.TLSv1_METHOD)
            ctx.set_cipher_list('RC4, AES256')
            tls = SSL.Connection(ctx,None)
            tls.set_connect_state()
            while True:
                try:
                    tls.do_handshake()
                except SSL.WantReadError:
                    data = tls.bio_read(4096)
                    self.sendTDS(TDS_PRE_LOGIN, data,0)
                    tds = self.recvTDS()
                    tls.bio_write(tds['Data'])
                else:
                    break

            # SSL and TLS limitation: Secure Socket Layer (SSL) and its replacement, 
            # Transport Layer Security(TLS), limit data fragments to 16k in size.
            self.packetSize = 16*1024-1
            self.tlsSocket = tls 


        login = TDS_LOGIN()

        login['HostName'] = (''.join([random.choice(string.ascii_letters) for i in range(8)])).encode('utf-16le')
        login['AppName']  = (''.join([random.choice(string.ascii_letters) for i in range(8)])).encode('utf-16le')
        login['ServerName'] = self.server.encode('utf-16le')
        login['CltIntName']  = login['AppName']
        login['ClientPID'] = random.randint(0,1024)
        login['PacketSize'] = self.packetSize
        if database is not None:
            login['Database'] = database.encode('utf-16le')
        login['OptionFlags2'] = TDS_INIT_LANG_FATAL | TDS_ODBC_ON

        if useWindowsAuth is True:
            login['OptionFlags2'] |= TDS_INTEGRATED_SECURITY_ON
            # NTLMSSP Negotiate
            auth = ntlm.getNTLMSSPType1('','')
            login['SSPI'] = auth.getData()
        else:
            login['UserName'] = username.encode('utf-16le')
            login['Password'] = self.encryptPassword(password.encode('utf-16le'))
            login['SSPI'] = ''


        login['Length'] = len(login.getData())

        # Send the NTLMSSP Negotiate or SQL Auth Packet
        self.sendTDS(TDS_LOGIN7, login.getData())

        # According to the specs, if encryption is not required, we must encrypt just 
        # the first Login packet :-o 
        if resp['Encryption'] == TDS_ENCRYPT_OFF:
            self.tlsSocket = None

        tds = self.recvTDS()


        if useWindowsAuth is True:
            serverChallenge = tds['Data'][3:]

            # Generate the NTLM ChallengeResponse AUTH 
            type3, exportedSessionKey = ntlm.getNTLMSSPType3(auth, serverChallenge, username, password, domain, lmhash, nthash)

            self.sendTDS(TDS_SSPI, type3.getData())
            tds = self.recvTDS()

        self.replies = self.parseReply(tds['Data'])

        if TDS_LOGINACK_TOKEN in self.replies:
            return True
        else:
            return False


    def processColMeta(self):
        for col in self.colMeta:
            if col['Type'] in [TDS_NVARCHARTYPE, TDS_NCHARTYPE, TDS_NTEXTTYPE]:
                col['Length'] = col['TypeData']//2
                fmt = '%%-%ds' 
            elif col['Type'] in [TDS_GUIDTYPE]:
                col['Length'] = 36
                fmt = '%%%ds' 
            elif col['Type'] in [TDS_DECIMALNTYPE,TDS_NUMERICNTYPE]:
                col['Length'] = ord(col['TypeData'][0:1])
                fmt = '%%%ds' 
            elif col['Type'] in [TDS_DATETIMNTYPE]:
                col['Length'] = 19
                fmt = '%%-%ds' 
            elif col['Type'] in [TDS_INT4TYPE, TDS_INTNTYPE]:
                col['Length'] = 11
                fmt = '%%%ds' 
            elif col['Type'] in [TDS_FLTNTYPE, TDS_MONEYNTYPE]:
                col['Length'] = 25
                fmt = '%%%ds' 
            elif col['Type'] in [TDS_BITNTYPE, TDS_BIGCHARTYPE]:
                col['Length'] = col['TypeData']
                fmt = '%%%ds' 
            elif col['Type'] in [TDS_BIGBINARYTYPE, TDS_BIGVARBINTYPE]:
                col['Length'] = col['TypeData'] * 2
                fmt = '%%%ds' 
            elif col['Type'] in [TDS_TEXTTYPE, TDS_BIGVARCHRTYPE]:
                col['Length'] = col['TypeData']
                fmt = '%%-%ds'
            else:
                col['Length'] = 10
                fmt = '%%%ds'

            if len(col['Name']) > col['Length']:
                col['Length'] = len(col['Name'])
            elif col['Length'] > self.MAX_COL_LEN:
                col['Length'] = self.MAX_COL_LEN

            col['Format'] = fmt % col['Length']


    def printColumnsHeader(self):
        if len(self.colMeta) == 0:
            return
        for col in self.colMeta:
            self.__rowsPrinter.logMessage(col['Format'] % col['Name'] + self.COL_SEPARATOR)
        self.__rowsPrinter.logMessage('\n')
        for col in self.colMeta:
            self.__rowsPrinter.logMessage('-'*col['Length'] + self.COL_SEPARATOR)
        self.__rowsPrinter.logMessage('\n')


    def printRows(self):
        if self.lastError is True:
            return
        self.processColMeta()
        self.printColumnsHeader()
        for row in self.rows:
            for col in self.colMeta:
                self.__rowsPrinter.logMessage(col['Format'] % row[col['Name']] + self.COL_SEPARATOR)
            self.__rowsPrinter.logMessage('\n')

    def printReplies(self):
        for keys in list(self.replies.keys()):
            for i, key in enumerate(self.replies[keys]):
                if key['TokenType'] == TDS_ERROR_TOKEN:
                    error =  "ERROR(%s): Line %d: %s" % (key['ServerName'].decode('utf-16le'), key['LineNumber'], key['MsgText'].decode('utf-16le'))                                      
                    self.lastError = SQLErrorException("ERROR: Line %d: %s" % (key['LineNumber'], key['MsgText'].decode('utf-16le')))
                    LOG.error(error)

                elif key['TokenType'] == TDS_INFO_TOKEN:
                    LOG.info("INFO(%s): Line %d: %s" % (key['ServerName'].decode('utf-16le'), key['LineNumber'], key['MsgText'].decode('utf-16le')))

                elif key['TokenType'] == TDS_LOGINACK_TOKEN:
                    LOG.info("ACK: Result: %s - %s (%d%d %d%d) " % (key['Interface'], key['ProgName'].decode('utf-16le'), key['MajorVer'], key['MinorVer'], key['BuildNumHi'], key['BuildNumLow']))

                elif key['TokenType'] == TDS_ENVCHANGE_TOKEN:
                    if key['Type'] in (TDS_ENVCHANGE_DATABASE, TDS_ENVCHANGE_LANGUAGE, TDS_ENVCHANGE_CHARSET, TDS_ENVCHANGE_PACKETSIZE):
                        record = TDS_ENVCHANGE_VARCHAR(key['Data'])
                        if record['OldValue'] == '':
                            record['OldValue'] = 'None'.encode('utf-16le')
                        elif record['NewValue'] == '':
                            record['NewValue'] = 'None'.encode('utf-16le')
                        if key['Type'] == TDS_ENVCHANGE_DATABASE:
                            _type = 'DATABASE'
                        elif key['Type'] == TDS_ENVCHANGE_LANGUAGE:
                            _type = 'LANGUAGE'
                        elif key['Type'] == TDS_ENVCHANGE_CHARSET:
                            _type = 'CHARSET'
                        elif key['Type'] == TDS_ENVCHANGE_PACKETSIZE:
                            _type = 'PACKETSIZE'
                        else:
                            _type = "%d" % key['Type']                 
                        LOG.info("ENVCHANGE(%s): Old Value: %s, New Value: %s" % (_type,record['OldValue'].decode('utf-16le'), record['NewValue'].decode('utf-16le')))
       
    def parseRow(self,token,tuplemode=False):
        # TODO: This REALLY needs to be improved. Right now we don't support correctly all the data types
        # help would be appreciated ;) 
        if len(token) == 1:
            return 0

        row = [] if tuplemode else {}

        origDataLen = len(token['Data'])
        data = token['Data']
        for col in self.colMeta:
            _type = col['Type']
            if (_type == TDS_NVARCHARTYPE) |\
               (_type == TDS_NCHARTYPE):
                #print "NVAR 0x%x" % _type
                charLen = struct.unpack('<H',data[:struct.calcsize('<H')])[0]
                data = data[struct.calcsize('<H'):]
                if charLen != 0xFFFF:
                    value = data[:charLen].decode('utf-16le')
                    data = data[charLen:]
                else:
                    value = 'NULL'

            elif _type == TDS_BIGVARCHRTYPE:
                charLen = struct.unpack('<H',data[:struct.calcsize('<H')])[0]
                data = data[struct.calcsize('<H'):]
                if charLen != 0xFFFF:
                    value = data[:charLen]
                    data = data[charLen:]
                else:
                    value = 'NULL'

            elif _type == TDS_GUIDTYPE:
                uuidLen = ord(data[0:1])
                data = data[1:]
                if uuidLen > 0:
                    uu = data[:uuidLen]
                    value = uuid.bin_to_string(uu)
                    data = data[uuidLen:]
                else:
                    value = 'NULL'
                
            elif (_type == TDS_NTEXTTYPE) |\
                 (_type == TDS_IMAGETYPE) :
                # Skip the pointer data
                charLen = ord(data[0:1])
                if charLen == 0:
                    value = 'NULL'
                    data = data[1:]
                else:
                    data = data[1+charLen+8:]
                    charLen = struct.unpack('<L',data[:struct.calcsize('<L')])[0]
                    data = data[struct.calcsize('<L'):]
                    if charLen != 0xFFFF:
                        if _type == TDS_NTEXTTYPE:
                            value = data[:charLen].decode('utf-16le')
                        else:
                            value = binascii.b2a_hex(data[:charLen])
                        data = data[charLen:]
                    else:
                        value = 'NULL'
                
            elif _type == TDS_TEXTTYPE:
                # Skip the pointer data
                charLen = ord(data[0:1])
                if charLen == 0:
                    value = 'NULL'
                    data = data[1:]
                else:
                    data = data[1+charLen+8:]
                    charLen = struct.unpack('<L',data[:struct.calcsize('<L')])[0]
                    data = data[struct.calcsize('<L'):]
                    if charLen != 0xFFFF:
                        value = data[:charLen]
                        data = data[charLen:]
                    else:
                        value = 'NULL'

            elif (_type == TDS_BIGVARBINTYPE) |\
                 (_type == TDS_BIGBINARYTYPE):
                charLen = struct.unpack('<H',data[:struct.calcsize('<H')])[0]
                data = data[struct.calcsize('<H'):]
                if charLen != 0xFFFF:
                    value = binascii.b2a_hex(data[:charLen])
                    data = data[charLen:]
                else:
                    value = 'NULL'

            elif (_type == TDS_DATETIM4TYPE) |\
                 (_type == TDS_DATETIMNTYPE) |\
                 (_type == TDS_DATETIMETYPE):
                value = ''    
                if _type == TDS_DATETIMNTYPE:
                    # For DATETIMNTYPE, the only valid lengths are 0x04 and 0x08, which map to smalldatetime and
                    # datetime SQL data _types respectively.
                    if ord(data[0:1]) == 4:
                        _type = TDS_DATETIM4TYPE
                    elif ord(data[0:1]) == 8:
                        _type = TDS_DATETIMETYPE
                    else:
                        value = 'NULL'
                    data = data[1:]
                if _type == TDS_DATETIMETYPE:
                    # datetime is represented in the following sequence:
                    # * One 4-byte signed integer that represents the number of days since January 1, 1900. Negative
                    #   numbers are allowed to represents dates since January 1, 1753.
                    # * One 4-byte unsigned integer that represents the number of one three-hundredths of a second
                    #  (300 counts per second) elapsed since 12 AM that day.
                    dateValue = struct.unpack('<l',data[:4])[0]
                    data = data[4:]
                    if dateValue < 0:
                        baseDate = datetime.date(1753,1,1)
                    else:
                        baseDate = datetime.date(1900,1,1)
                    timeValue = struct.unpack('<L',data[:4])[0]
                    data = data[4:] 
                elif _type == TDS_DATETIM4TYPE:
                    # Small datetime
                    # 2.2.5.5.1.8
                    # Date/Times
                    # smalldatetime is represented in the following sequence:
                    # * One 2-byte unsigned integer that represents the number of days since January 1, 1900.
                    # * One 2-byte unsigned integer that represents the number of minutes elapsed since 12 AM that
                    #   day.
                    dateValue = struct.unpack('<H',data[:struct.calcsize('<H')])[0]
                    data = data[struct.calcsize('<H'):]
                    timeValue = struct.unpack('<H',data[:struct.calcsize('<H')])[0]
                    data = data[struct.calcsize('<H'):]
                    baseDate = datetime.date(1900,1,1)
                if value != 'NULL':
                    dateValue = datetime.date.fromordinal(baseDate.toordinal() + dateValue)
                    hours, mod = divmod(timeValue//300, 60*60)
                    minutes, second = divmod(mod, 60)
                    value = datetime.datetime(dateValue.year, dateValue.month, dateValue.day, hours, minutes, second)

            elif (_type == TDS_INT4TYPE) |\
                 (_type == TDS_MONEY4TYPE) |\
                 (_type == TDS_FLT4TYPE):
                #print "INT4"
                value = struct.unpack('<l',data[:struct.calcsize('<l')])[0]
                data = data[struct.calcsize('<l'):]

            elif _type == TDS_FLTNTYPE:
                valueSize = ord(data[:1])
                if valueSize == 4:
                    fmt = '<f'
                elif valueSize == 8:
                    fmt = '<d'

                data = data[1:]

                if valueSize > 0:
                    value = struct.unpack(fmt,data[:valueSize])[0]
                    data = data[valueSize:]
                else:
                    value = 'NULL'

            elif _type == TDS_MONEYNTYPE:
                valueSize = ord(data[:1])
                if valueSize == 4:
                    fmt = '<l'
                elif valueSize == 8:
                    fmt = '<q'

                data = data[1:]

                if valueSize > 0:
                    value = struct.unpack(fmt,data[:valueSize])[0]
                    if valueSize == 4:
                        value = float(value) // math.pow(10,4)
                    else:
                        value = float(value >> 32) // math.pow(10,4)
                    data = data[valueSize:]
                else:
                    value = 'NULL'

                
            elif _type == TDS_BIGCHARTYPE:
                #print "BIGC"
                charLen = struct.unpack('<H',data[:struct.calcsize('<H')])[0]
                data = data[struct.calcsize('<H'):]
                value = data[:charLen]
                data = data[charLen:]

            elif (_type == TDS_INT8TYPE) |\
                 (_type == TDS_FLT8TYPE) |\
                 (_type == TDS_MONEYTYPE):
                #print "DATETIME"
                value = struct.unpack('<q',data[:struct.calcsize('<q')])[0]
                data = data[struct.calcsize('<q'):]


            elif _type == TDS_INT2TYPE:
                #print "INT2TYPE"
                value = struct.unpack('<H',(data[:2]))[0]
                data = data[2:]

            elif _type == TDS_DATENTYPE:
                # date is represented as one 3-byte unsigned integer that represents the number of days since
                # January 1, year 1.
                valueSize = ord(data[:1])
                data = data[1:]
                if valueSize > 0:
                    dateBytes = data[:valueSize]
                    dateValue = struct.unpack('<L','\x00'+dateBytes)[0]
                    value = datetime.date.fromtimestamp(dateValue)
                    data = data[valueSize:]
                else:
                    value = 'NULL'

            elif (_type == TDS_BITTYPE) |\
                 (_type == TDS_INT1TYPE):
                #print "BITTYPE"
                value = ord(data[:1])
                data = data[1:]

            elif (_type == TDS_NUMERICNTYPE) |\
                 (_type == TDS_DECIMALNTYPE):
                valueLen = ord(data[:1])
                data = data[1:]
                value = data[:valueLen]
                data = data[valueLen:]
                precision = ord(col['TypeData'][1:2])
                scale = ord(col['TypeData'][2:3])
                if valueLen > 0:
                    isPositiveSign = ord(value[0:1])
                    if (valueLen-1) == 2:
                        fmt = '<H'
                    elif (valueLen-1) == 4:
                        fmt = '<L'
                    elif (valueLen-1) == 8:
                        fmt = '<Q'
                    else:
                        # Still don't know how to handle higher values
                        value = "TODO: Interpret TDS_NUMERICNTYPE correctly"
                    number = struct.unpack(fmt, value[1:])[0]
                    number //= math.pow(precision, scale)
                    if isPositiveSign == 0:
                        number *= -1 
                    value = number
                else:
                    value = 'NULL'

            elif _type == TDS_BITNTYPE:
                #print "BITNTYPE"
                valueSize = ord(data[:1])
                data = data[1:]
                if valueSize > 0:
                    if valueSize == 1:
                        value = ord(data[:valueSize])
                    else:
                        value = data[:valueSize]
                else:
                    value = 'NULL'
                data = data[valueSize:]

            elif _type == TDS_INTNTYPE:
                valueSize = ord(data[:1])
                if valueSize == 1:
                    fmt = '<B'
                elif valueSize == 2:
                    fmt = '<h'
                elif valueSize == 4:
                    fmt = '<l'
                elif valueSize == 8:
                    fmt = '<q'
                else:
                    fmt = ''

                data = data[1:]

                if valueSize > 0:
                    value = struct.unpack(fmt,data[:valueSize])[0]
                    data = data[valueSize:]
                else:
                    value = 'NULL'
            elif _type == TDS_SSVARIANTTYPE:
                raise Exception("ParseRow: SQL Variant type not yet supported :(")
            else:
                raise Exception("ParseROW: Unsupported data type: 0%x" % _type)

            if tuplemode:
                row.append(value)
            else:
                row[col['Name']] = value


        self.rows.append(row)

        return origDataLen - len(data)

    def parseColMetaData(self, token):
        # TODO Add support for more data types!
        count = token['Count']
        if count == 0xFFFF:
            return 0

        self.colMeta = []
        origDataLen = len(token['Data'])
        data = token['Data']
        for i in range(count):
            column = {}
            userType = struct.unpack('<H',data[:struct.calcsize('<H')])[0]
            data = data[struct.calcsize('<H'):]
            flags = struct.unpack('<H',data[:struct.calcsize('<H')])[0]
            data = data[struct.calcsize('<H'):]
            colType = struct.unpack('<B',data[:struct.calcsize('<B')])[0]
            data = data[struct.calcsize('<B'):]
            if (colType == TDS_BITTYPE)    |\
                 (colType == TDS_INT1TYPE)   |\
                 (colType == TDS_INT2TYPE)   |\
                 (colType == TDS_INT8TYPE)   |\
                 (colType == TDS_DATETIMETYPE) |\
                 (colType == TDS_DATETIM4TYPE) |\
                 (colType == TDS_FLT4TYPE)   |\
                 (colType == TDS_FLT8TYPE)   |\
                 (colType == TDS_MONEYTYPE)  |\
                 (colType == TDS_MONEY4TYPE) |\
                 (colType == TDS_DATENTYPE)  |\
                 (colType == TDS_INT4TYPE):
                typeData = ''
            elif (colType == TDS_INTNTYPE) |\
                 (colType == TDS_TIMENTYPE) |\
                 (colType == TDS_DATETIME2NTYPE) |\
                 (colType == TDS_DATETIMEOFFSETNTYPE) |\
                 (colType == TDS_FLTNTYPE) |\
                 (colType == TDS_MONEYNTYPE) |\
                 (colType == TDS_GUIDTYPE) |\
                 (colType == TDS_BITNTYPE):
                typeData = ord(data[0:1])
                data = data[1:]

            elif colType == TDS_DATETIMNTYPE:
                # For DATETIMNTYPE, the only valid lengths are 0x04 and 0x08, which map to smalldatetime and
                # datetime SQL data types respectively.
                typeData = ord(data[0:1])
                data = data[1:]

            elif (colType == TDS_BIGVARBINTYPE) |\
                 (colType == TDS_BIGBINARYTYPE) |\
                 (colType == TDS_NCHARTYPE)     |\
                 (colType == TDS_NVARCHARTYPE)  |\
                 (colType == TDS_BIGVARCHRTYPE) |\
                 (colType == TDS_BIGCHARTYPE):
                typeData = struct.unpack('<H',data[:2])[0]
                data = data[2:]
            elif (colType == TDS_DECIMALNTYPE) |\
                 (colType == TDS_NUMERICNTYPE) |\
                 (colType == TDS_DECIMALTYPE):
                typeData = data[:3]
                data = data[3:]
            elif (colType == TDS_IMAGETYPE) |\
                 (colType == TDS_TEXTTYPE) |\
                 (colType == TDS_XMLTYPE)  |\
                 (colType == TDS_SSVARIANTTYPE) |\
                 (colType == TDS_NTEXTTYPE):
                typeData = struct.unpack('<L',data[:4])[0]
                data = data[4:]
            else:
                raise Exception("Unsupported data type: 0x%x" % colType)

            # Collation exceptions:
            if (colType == TDS_NTEXTTYPE) |\
               (colType == TDS_BIGCHARTYPE)  |\
               (colType == TDS_BIGVARCHRTYPE)  |\
               (colType == TDS_NCHARTYPE)  |\
               (colType == TDS_NVARCHARTYPE)  |\
               (colType == TDS_TEXTTYPE):
                # Skip collation
                data = data[5:]

            # PartTableName exceptions:
            if (colType == TDS_IMAGETYPE) |\
               (colType == TDS_TEXTTYPE) |\
               (colType == TDS_NTEXTTYPE):
                # This types have Table Elements, we just discard them for now.
                # ToDo parse this correctly!
                # Get the Length
                dataLen = struct.unpack('<H',data[:2])[0]
                data = data[2:]
                # skip the text
                data = data[dataLen*2:]

            colNameLength = struct.unpack('<B',data[:struct.calcsize('<B')])[0]
            data = data[struct.calcsize('<B'):]
            colName = data[:colNameLength*2].decode('utf-16le')
            data = data[colNameLength*2:]
            column['Name'] = colName
            column['Type'] = colType
            column['TypeData'] = typeData
            column['Flags'] = flags
            self.colMeta.append(column)

        return origDataLen - len(data)

    def parseReply(self, tokens,tuplemode=False):
        if len(tokens) == 0:
            return False

        replies = {} 
        while len(tokens) > 0:
            tokenID = struct.unpack('B',tokens[0:1])[0]
            if tokenID == TDS_ERROR_TOKEN:
                token = TDS_INFO_ERROR(tokens)
            elif tokenID == TDS_RETURNSTATUS_TOKEN:
                token = TDS_RETURNSTATUS(tokens)
            elif tokenID == TDS_INFO_TOKEN:
                token = TDS_INFO_ERROR(tokens)
            elif tokenID == TDS_LOGINACK_TOKEN:
                token = TDS_LOGIN_ACK(tokens)
            elif tokenID == TDS_ENVCHANGE_TOKEN:
                token = TDS_ENVCHANGE(tokens)
                if token['Type'] is TDS_ENVCHANGE_PACKETSIZE:
                    record = TDS_ENVCHANGE_VARCHAR(token['Data'])
                    self.packetSize = int( record['NewValue'].decode('utf-16le') )
                elif token['Type'] is TDS_ENVCHANGE_DATABASE:
                    record = TDS_ENVCHANGE_VARCHAR(token['Data'])
                    self.currentDB =  record['NewValue'].decode('utf-16le') 

            elif (tokenID == TDS_DONEINPROC_TOKEN) |\
                 (tokenID == TDS_DONEPROC_TOKEN): 
                token = TDS_DONEINPROC(tokens)
            elif tokenID == TDS_ORDER_TOKEN:
                token = TDS_ORDER(tokens)
            elif tokenID == TDS_ROW_TOKEN:
                #print "ROW"
                token = TDS_ROW(tokens)
                tokenLen = self.parseRow(token,tuplemode)
                token['Data'] = token['Data'][:tokenLen]
            elif tokenID == TDS_COLMETADATA_TOKEN:
                #print "COLMETA"
                token = TDS_COLMETADATA(tokens)
                tokenLen = self.parseColMetaData(token)
                token['Data'] = token['Data'][:tokenLen]
            elif tokenID == TDS_DONE_TOKEN:
                token = TDS_DONE(tokens)
            else:
                LOG.error("Unknown Token %x" % tokenID)
                return replies

            if (tokenID in replies) is not True:
                replies[tokenID] = list()

            replies[tokenID].append(token)
            tokens = tokens[len(token):]
            #print "TYPE 0x%x, LEN: %d" %(tokenID, len(token))
            #print repr(tokens[:10])

        return replies

    def batch(self, cmd,tuplemode=False,wait=True):
        # First of all we clear the rows, colMeta and lastError
        self.rows = []
        self.colMeta = []
        self.lastError = False
        self.sendTDS(TDS_SQL_BATCH, (cmd+'\r\n').encode('utf-16le'))
        if wait:
            tds = self.recvTDS()
            self.replies = self.parseReply(tds['Data'],tuplemode)
            return self.rows
        else:
            return True
        
    
    def batchStatement(self, cmd,tuplemode=False):
        # First of all we clear the rows, colMeta and lastError
        self.rows = []
        self.colMeta = []
        self.lastError = False
        self.sendTDS(TDS_SQL_BATCH, (cmd+'\r\n').encode('utf-16le'))
        #self.recvTDS()        

            
    # Handy alias
    sql_query = batch

    def changeDB(self, db):        
        if db != self.currentDB:
            chdb = 'use %s' % db            
            self.batch(chdb)
            self.printReplies()

    def RunSQLQuery(self,db,sql_query,tuplemode=False,wait=True,**kwArgs):
        db = db or 'master'
        self.changeDB(db)
        self.printReplies()
        ret = self.batch(sql_query,tuplemode,wait)
        if wait:
            self.printReplies()
        if self.lastError:
            raise self.lastError
        if self.lastError:
            raise self.lastError
        return ret
    
    def RunSQLStatement(self,db,sql_query,wait=True,**kwArgs):
        self.RunSQLQuery(db,sql_query,wait=wait)
        if self.lastError:
            raise self.lastError
        return True
