This file is indexed.

/usr/lib/python2.7/dist-packages/impacket/nmb.py is in python-impacket 0.9.15-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
# Copyright (c) 2003-2016 CORE Security Technologies
#
# This software is provided under under a slightly modified version
# of the Apache Software License. See the accompanying LICENSE file
# for more information.
#


# -*- mode: python; tab-width: 4 -*-
#
# Copyright (C) 2001 Michael Teo <michaelteo@bigfoot.com>
# nmb.py - NetBIOS library
#
# This software is provided 'as-is', without any express or implied warranty. 
# In no event will the author be held liable for any damages arising from the 
# use of this software.
#
# Permission is granted to anyone to use this software for any purpose, 
# including commercial applications, and to alter it and redistribute it 
# freely, subject to the following restrictions:
#
# 1. The origin of this software must not be misrepresented; you must not 
#    claim that you wrote the original software. If you use this software 
#    in a product, an acknowledgment in the product documentation would be
#    appreciated but is not required.
#
# 2. Altered source versions must be plainly marked as such, and must not be 
#    misrepresented as being the original software.
#
# 3. This notice cannot be removed or altered from any source distribution.
#
# Altered source done by Alberto Solino (@agsolino)

import socket
import string
import re
import select
import errno
from random import randint
from struct import pack, unpack
import time

from structure import Structure

CVS_REVISION = '$Revision: 526 $'

# Taken from socket module reference
INADDR_ANY = '0.0.0.0'
BROADCAST_ADDR = '<broadcast>'

# Default port for NetBIOS name service
NETBIOS_NS_PORT = 137
# Default port for NetBIOS session service
NETBIOS_SESSION_PORT = 139

# Default port for SMB session service
SMB_SESSION_PORT = 445

# Owner Node Type Constants
NODE_B = 0x0000
NODE_P = 0x2000
NODE_M = 0x4000
NODE_RESERVED = 0x6000
NODE_GROUP = 0x8000
NODE_UNIQUE = 0x0

# Name Type Constants
TYPE_UNKNOWN = 0x01
TYPE_WORKSTATION = 0x00
TYPE_CLIENT = 0x03
TYPE_SERVER = 0x20
TYPE_DOMAIN_MASTER = 0x1B
TYPE_DOMAIN_CONTROLLER = 0x1C
TYPE_MASTER_BROWSER = 0x1D
TYPE_BROWSER = 0x1E
TYPE_NETDDE  = 0x1F
TYPE_STATUS = 0x21

# Opcodes values
OPCODE_QUERY = 0
OPCODE_REGISTRATION = 0x5
OPCODE_RELEASE = 0x6
OPCODE_WACK = 0x7
OPCODE_REFRESH = 0x8
OPCODE_REQUEST = 0
OPCODE_RESPONSE = 0x10

# NM_FLAGS
NM_FLAGS_BROADCAST = 0x1
NM_FLAGS_UNICAST = 0
NM_FLAGS_RA = 0x8
NM_FLAGS_RD = 0x10
NM_FLAGS_TC = 0x20
NM_FLAGS_AA = 0x40

# QUESTION_TYPE
QUESTION_TYPE_NB = 0x20     # NetBIOS general Name Service Resource Record
QUESTION_TYPE_NBSTAT = 0x21 # NetBIOS NODE STATUS Resource Record
# QUESTION_CLASS
QUESTION_CLASS_IN = 0x1     # Internet class

# RR_TYPE Resource Record Type code
RR_TYPE_A = 0x1               # IP address Resource Record
RR_TYPE_NS = 0x2              # Name Server Resource Record
RR_TYPE_NULL = 0xA          # NULL Resource Record
RR_TYPE_NB = 0x20           # NetBIOS general Name Service Resource Record
RR_TYPE_NBSTAT = 0x21       # NetBIOS NODE STATUS Resource Record

# Resource Record Class
RR_CLASS_IN = 1             # Internet class

# RCODE values
RCODE_FMT_ERR   = 0x1       # Format Error.  Request was invalidly formatted.
RCODE_SRV_ERR   = 0x2       # Server failure.  Problem with NBNS, cannot process name.
RCODE_IMP_ERR   = 0x4       # Unsupported request error.  Allowable only for challenging NBNS when gets an Update type
                            # registration request.
RCODE_RFS_ERR   = 0x5       # Refused error.  For policy reasons server will not register this name from this host.
RCODE_ACT_ERR   = 0x6       # Active error.  Name is owned by another node.
RCODE_CFT_ERR   = 0x7       # Name in conflict error.  A UNIQUE name is owned by more than one node.

# NAME_FLAGS
NAME_FLAGS_PRM = 0x0200       # Permanent Name Flag.  If one (1) then entry is for the permanent node name.  Flag is zero
                            # (0) for all other names.
NAME_FLAGS_ACT = 0x0400       # Active Name Flag.  All entries have this flag set to one (1).
NAME_FLAG_CNF  = 0x0800       # Conflict Flag.  If one (1) then name on this node is in conflict.
NAME_FLAG_DRG  = 0x1000       # Deregister Flag.  If one (1) then this name is in the process of being deleted.

NAME_TYPES = { TYPE_UNKNOWN: 'Unknown', TYPE_WORKSTATION: 'Workstation', TYPE_CLIENT: 'Client',
               TYPE_SERVER: 'Server', TYPE_MASTER_BROWSER: 'Master Browser', TYPE_BROWSER: 'Browser Server',
               TYPE_DOMAIN_MASTER: 'Domain Master' , TYPE_NETDDE: 'NetDDE Server'}
# NetBIOS Session Types
NETBIOS_SESSION_MESSAGE = 0x0
NETBIOS_SESSION_REQUEST = 0x81
NETBIOS_SESSION_POSITIVE_RESPONSE = 0x82
NETBIOS_SESSION_NEGATIVE_RESPONSE = 0x83
NETBIOS_SESSION_RETARGET_RESPONSE = 0x84
NETBIOS_SESSION_KEEP_ALIVE = 0x85


def strerror(errclass, errcode):
    if errclass == ERRCLASS_OS:
        return 'OS Error', str(errcode)
    elif errclass == ERRCLASS_QUERY:
        return 'Query Error', QUERY_ERRORS.get(errcode, 'Unknown error')
    elif errclass == ERRCLASS_SESSION:
        return 'Session Error', SESSION_ERRORS.get(errcode, 'Unknown error')
    else:
        return 'Unknown Error Class', 'Unknown Error'
    
    

class NetBIOSError(Exception): pass
class NetBIOSTimeout(Exception):
    def __init__(self, message = 'The NETBIOS connection with the remote host timed out.'):
        Exception.__init__(self, message)

class NBResourceRecord:
    def __init__(self, data = 0):
        self._data = data
        try:
            if self._data:
                self.rr_name = (re.split('\x00',data))[0]
                offset = len(self.rr_name)+1
                self.rr_type  = unpack('>H', self._data[offset:offset+2])[0]
                self.rr_class = unpack('>H', self._data[offset+2: offset+4])[0]
                self.ttl = unpack('>L',self._data[offset+4:offset+8])[0]
                self.rdlength = unpack('>H', self._data[offset+8:offset+10])[0]
                self.rdata = self._data[offset+10:offset+10+self.rdlength]
                offset = self.rdlength - 2
                self.unit_id = data[offset:offset+6]
            else:
                self.rr_name = ''
                self.rr_type = 0
                self.rr_class = 0
                self.ttl = 0
                self.rdlength = 0
                self.rdata = ''
                self.unit_id = ''
        except Exception:
                raise NetBIOSError( 'Wrong packet format ' )

    def set_rr_name(self, name):
        self.rr_name = name
    def set_rr_type(self, name):
        self.rr_type = name
    def set_rr_class(self,cl):
        self.rr_class = cl
    def set_ttl(self,ttl):
        self.ttl = ttl
    def set_rdata(self,rdata):
        self.rdata = rdata
        self.rdlength = len(rdata)
    def get_unit_id(self):
        return self.unit_id
    def get_rr_name(self):
        return self.rr_name
    def get_rr_class(self):
        return self.rr_class
    def get_ttl(self):
        return self.ttl
    def get_rdlength(self):
        return self.rdlength
    def get_rdata(self):
        return self.rdata
    def rawData(self):
        return self.rr_name + pack('!HHLH',self.rr_type, self.rr_class, self.ttl, self.rdlength) + self.rdata

class NBNodeStatusResponse(NBResourceRecord):
    def __init__(self, data = 0):
        NBResourceRecord.__init__(self,data)
        self.num_names = 0
        self.node_names = [ ]
        self.statstics = ''
        self.mac = '00-00-00-00-00-00'
        try:
            if data:
                self._data = self.get_rdata()
                self.num_names = unpack('>B',self._data[:1])[0]
                offset = 1
                for i in range(0, self.num_names):
                    name = self._data[offset:offset + 15]
                    type,flags = unpack('>BH', self._data[offset + 15: offset + 18])
                    offset += 18
                    self.node_names.append(NBNodeEntry(name, type ,flags))
                self.set_mac_in_hexa(self.get_unit_id())
        except Exception:
            raise NetBIOSError( 'Wrong packet format ' )

    def set_mac_in_hexa(self, data):
        data_aux = ''
        for d in data:
            if data_aux == '':
                data_aux = '%02x' % ord(d)
            else:
                data_aux += '-%02x' % ord(d)
        self.mac = string.upper(data_aux)

    def get_num_names(self):
        return self.num_names
    def get_mac(self):
        return self.mac
    def set_num_names(self, num):
        self.num_names = num
    def get_node_names(self):
        return self.node_names
    def add_node_name(self,node_names):
        self.node_names.append(node_names)
        self.num_names += 1
    def rawData(self):
        res = pack('!B', self.num_names )
        for i in range(0, self.num_names):
            res += self.node_names[i].rawData()

class NBPositiveNameQueryResponse(NBResourceRecord):
    def __init__(self, data = 0):
        NBResourceRecord.__init__(self, data)
        self.addr_entries = [ ]
        if data:
                self._data = self.get_rdata()
                _qn_length, qn_name, qn_scope = decode_name(data)
                self._netbios_name = string.rstrip(qn_name[:-1]) + qn_scope
                self._name_type = ord(qn_name[-1])
                self._nb_flags = unpack('!H', self._data[:2])
                offset = 2
                while offset<len(self._data):
                    self.addr_entries.append('%d.%d.%d.%d' % unpack('4B', (self._data[offset:offset+4])))
                    offset += 4
    
    def get_netbios_name(self):
        return self._netbios_name
    
    def get_name_type(self):
        return self._name_type
    
    def get_addr_entries(self):
        return self.addr_entries
                
class NetBIOSPacket:
    """ This is a packet as defined in RFC 1002 """
    def __init__(self, data = 0):
        self.name_trn_id = 0x0  # Transaction ID for Name Service Transaction.
                                #   Requestor places a unique value for each active
                                #   transaction.  Responder puts NAME_TRN_ID value
                                #   from request packet in response packet.
        self.opcode = 0         # Packet type code
        self.nm_flags = 0       # Flags for operation
        self.rcode = 0          # Result codes of request.
        self.qdcount = 0        # Unsigned 16 bit integer specifying the number of entries in the question section of a Name
        self.ancount = 0        # Unsigned 16 bit integer specifying the number of
                                # resource records in the answer section of a Name
                                # Service packet.
        self.nscount = 0        # Unsigned 16 bit integer specifying the number of
                                # resource records in the authority section of a
                                # Name Service packet.
        self.arcount = 0        # Unsigned 16 bit integer specifying the number of
                                # resource records in the additional records
                                # section of a Name Service packeT.
        self.questions = ''
        self.answers = ''
        if data == 0:
            self._data = ''
        else:
            try:
                self._data = data
                self.opcode = ord(data[2]) >> 3 
                self.nm_flags = ((ord(data[2]) & 0x3) << 4) | ((ord(data[3]) & 0xf0) >> 4)
                self.name_trn_id = unpack('>H', self._data[:2])[0]
                self.rcode = ord(data[3]) & 0x0f
                self.qdcount = unpack('>H', self._data[4:6])[0]
                self.ancount = unpack('>H', self._data[6:8])[0]
                self.nscount = unpack('>H', self._data[8:10])[0]
                self.arcount = unpack('>H', self._data[10:12])[0]
                self.answers = self._data[12:]
            except Exception:
                raise NetBIOSError( 'Wrong packet format ' )
            
    def set_opcode(self, opcode):
        self.opcode = opcode
    def set_trn_id(self, trn):
        self.name_trn_id = trn
    def set_nm_flags(self, nm_flags):
        self.nm_flags = nm_flags
    def set_rcode(self, rcode):
        self.rcode = rcode
    def addQuestion(self, question, qtype, qclass):
        self.qdcount += 1
        self.questions += question + pack('!HH',qtype,qclass)
    def get_trn_id(self):
        return self.name_trn_id
    def get_rcode(self):
        return self.rcode
    def get_nm_flags(self):
        return self.nm_flags
    def get_opcode(self):
        return self.opcode
    def get_qdcount(self):
        return self.qdcount
    def get_ancount(self):
        return self.ancount
    def get_nscount(self):
        return self.nscount
    def get_arcount(self):
        return self.arcount
    def rawData(self):
        secondWord = self.opcode << 11
        secondWord |= self.nm_flags << 4
        secondWord |= self.rcode
        data = pack('!HHHHHH', self.name_trn_id, secondWord , self.qdcount, self.ancount, self.nscount, self.arcount) + self.questions + self.answers
        return data
    def get_answers(self):
        return self.answers

class NBHostEntry:

    def __init__(self, nbname, nametype, ip):
        self.__nbname = nbname
        self.__nametype = nametype
        self.__ip = ip

    def get_nbname(self):
        return self.__nbname

    def get_nametype(self):
        return self.__nametype

    def get_ip(self):
        return self.__ip

    def __repr__(self):
        return '<NBHostEntry instance: NBname="' + self.__nbname + '", IP="' + self.__ip + '">'

class NBNodeEntry:
    
    def __init__(self, nbname, nametype, flags): 
        self.__nbname = string.ljust(nbname,17)
        self.__nametype = nametype
        self.__flags = flags
        self.__isgroup = flags & 0x8000
        self.__nodetype = flags & 0x6000
        self.__deleting = flags & 0x1000
        self.__isconflict = flags & 0x0800
        self.__isactive = flags & 0x0400
        self.__ispermanent = flags & 0x0200

    def get_nbname(self):
        return self.__nbname

    def get_nametype(self):
        return self.__nametype

    def is_group(self):
        return self.__isgroup

    def get_nodetype(self):
        return self.__nodetype

    def is_deleting(self):
        return self.__deleting

    def is_conflict(self):
        return self.__isconflict

    def is_active(self):
        return self.__isactive

    def is_permanent(self):
        return self.__ispermanent

    def set_nbname(self, name):
        self.__nbname = string.ljust(name,17)

    def set_nametype(self, type):
        self.__nametype = type

    def set_flags(self,flags):
        self.__flags = flags
        
    def __repr__(self):
        s = '<NBNodeEntry instance: NBname="' + self.__nbname + '" NameType="' + NAME_TYPES[self.__nametype] + '"'
        if self.__isactive:
            s += ' ACTIVE'
        if self.__isgroup:
            s += ' GROUP'
        if self.__isconflict:
            s += ' CONFLICT'
        if self.__deleting:
            s += ' DELETING'
        return s
    def rawData(self):
        return self.__nbname + pack('!BH',self.__nametype, self.__flags)


class NetBIOS:

    # Creates a NetBIOS instance without specifying any default NetBIOS domain nameserver.
    # All queries will be sent through the servport.
    def __init__(self, servport = NETBIOS_NS_PORT):
        self.__servport = NETBIOS_NS_PORT
        self.__nameserver = None
        self.__broadcastaddr = BROADCAST_ADDR
        self.mac = '00-00-00-00-00-00'

    def _setup_connection(self, dstaddr):
        port = randint(10000, 60000)
        af, socktype, proto, _canonname, _sa = socket.getaddrinfo(dstaddr, port, socket.AF_INET, socket.SOCK_DGRAM)[0]
        s = socket.socket(af, socktype, proto)
        has_bind = 1
        for _i in range(0, 10):
        # We try to bind to a port for 10 tries
            try:
                s.bind(( INADDR_ANY, randint(10000, 60000) ))
                s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
                has_bind = 1
            except socket.error:
                pass
        if not has_bind:
            raise NetBIOSError, ( 'Cannot bind to a good UDP port', ERRCLASS_OS, errno.EAGAIN )
        self.__sock = s

    # Set the default NetBIOS domain nameserver.
    def set_nameserver(self, nameserver):
        self.__nameserver = nameserver

    # Return the default NetBIOS domain nameserver, or None if none is specified.
    def get_nameserver(self):
        return self.__nameserver

    # Set the broadcast address to be used for query.
    def set_broadcastaddr(self, broadcastaddr):
        self.__broadcastaddr = broadcastaddr

    # Return the broadcast address to be used, or BROADCAST_ADDR if default broadcast address is used.   
    def get_broadcastaddr(self):
        return self.__broadcastaddr

    # Returns a NBPositiveNameQueryResponse instance containing the host information for nbname.
    # If a NetBIOS domain nameserver has been specified, it will be used for the query.
    # Otherwise, the query is broadcasted on the broadcast address.
    def gethostbyname(self, nbname, qtype = TYPE_WORKSTATION, scope = None, timeout = 1):
        return self.__queryname(nbname, self.__nameserver, qtype, scope, timeout)

    # Returns a list of NBNodeEntry instances containing node status information for nbname.
    # If destaddr contains an IP address, then this will become an unicast query on the destaddr.
    # Raises NetBIOSTimeout if timeout (in secs) is reached.
    # Raises NetBIOSError for other errors
    def getnodestatus(self, nbname, destaddr = None, type = TYPE_WORKSTATION, scope = None, timeout = 1):
        if destaddr:
            return self.__querynodestatus(nbname, destaddr, type, scope, timeout)
        else:
            return self.__querynodestatus(nbname, self.__nameserver, type, scope, timeout)

    def getnetbiosname(self, ip):
        entries = self.getnodestatus('*',ip)
        entries = filter(lambda x:x.get_nametype() == TYPE_SERVER, entries)
        return entries[0].get_nbname().strip()

    def getmacaddress(self):
        return self.mac

    def __queryname(self, nbname, destaddr, qtype, scope, timeout, retries = 0):
        self._setup_connection(destaddr)
        trn_id = randint(1, 32000)
        p = NetBIOSPacket()
        p.set_trn_id(trn_id)
        netbios_name = nbname.upper()
        qn_label = encode_name(netbios_name, qtype, scope)
        p.addQuestion(qn_label, QUESTION_TYPE_NB, QUESTION_CLASS_IN)
        p.set_nm_flags(NM_FLAGS_RD)
        if not destaddr:
            p.set_nm_flags(p.get_nm_flags() | NM_FLAGS_BROADCAST)
            destaddr = self.__broadcastaddr            
        req = p.rawData()
        
        tries = retries
        while 1:
            self.__sock.sendto(req, ( destaddr, self.__servport ))
            try:
                ready, _, _ = select.select([ self.__sock.fileno() ], [ ] , [ ], timeout)
                if not ready:
                    if tries:
                        # Retry again until tries == 0
                        tries -= 1
                    else:
                        raise NetBIOSTimeout
                else:
                    data, _ = self.__sock.recvfrom(65536, 0)
                    
                    res = NetBIOSPacket(data)
                    if res.get_trn_id() == p.get_trn_id():
                        if res.get_rcode():
                            if res.get_rcode() == 0x03:
                                return None
                            else:
                                raise NetBIOSError, ( 'Negative name query response', ERRCLASS_QUERY, res.get_rcode() )
                        
                        if res.get_ancount() != 1:
                            raise NetBIOSError( 'Malformed response')
                        
                        return NBPositiveNameQueryResponse(res.get_answers())
            except select.error, ex:
                if ex[0] != errno.EINTR and ex[0] != errno.EAGAIN:
                    raise NetBIOSError, ( 'Error occurs while waiting for response', ERRCLASS_OS, ex[0] )
                raise


    def __querynodestatus(self, nbname, destaddr, type, scope, timeout):
        self._setup_connection(destaddr)
        trn_id = randint(1, 32000)
        p = NetBIOSPacket()
        p.set_trn_id(trn_id)
        netbios_name = string.upper(nbname)
        qn_label = encode_name(netbios_name, type, scope)
        p.addQuestion(qn_label, QUESTION_TYPE_NBSTAT, QUESTION_CLASS_IN)

        if not destaddr:
            p.set_nm_flags(NM_FLAGS_BROADCAST)
            destaddr = self.__broadcastaddr            
        req = p.rawData()
        tries = 3
        while 1:
            try:
                self.__sock.sendto(req, 0, ( destaddr, self.__servport ))
                ready, _, _ = select.select([ self.__sock.fileno() ], [ ] , [ ], timeout)
                if not ready:
                    if tries:
                        # Retry again until tries == 0
                        tries -= 1
                    else:
                        raise NetBIOSTimeout
                else:
                    try:
                        data, _ = self.__sock.recvfrom(65536, 0)
                    except Exception, e:
                        raise NetBIOSError, "recvfrom error: %s" % str(e)
                    self.__sock.close()
                    res = NetBIOSPacket(data)
                    if res.get_trn_id() == p.get_trn_id():
                        if res.get_rcode():
                            if res.get_rcode() == 0x03:
                                # I'm just guessing here
                                raise NetBIOSError, "Cannot get data from server"
                            else:
                                raise NetBIOSError, ( 'Negative name query response', ERRCLASS_QUERY, res.get_rcode() )
                        answ = NBNodeStatusResponse(res.get_answers())
                        self.mac = answ.get_mac()
                        return answ.get_node_names()
            except select.error, ex:
                if ex[0] != errno.EINTR and ex[0] != errno.EAGAIN:
                    raise NetBIOSError, ( 'Error occurs while waiting for response', ERRCLASS_OS, ex[0] )
            except socket.error, ex:
                raise NetBIOSError, 'Connection error: %s' % str(ex)

# Perform first and second level encoding of name as specified in RFC 1001 (Section 4)
def encode_name(name, type, scope):
    if name == '*':
        name += '\0' * 15
    elif len(name) > 15:
        name = name[:15] + chr(type)
    else:
        name = string.ljust(name, 15) + chr(type)
        
    encoded_name = chr(len(name) * 2) + re.sub('.', _do_first_level_encoding, name)
    if scope:
        encoded_scope = ''
        for s in string.split(scope, '.'):
            encoded_scope = encoded_scope + chr(len(s)) + s
        return encoded_name + encoded_scope + '\0'
    else:
        return encoded_name + '\0'

# Internal method for use in encode_name()
def _do_first_level_encoding(m):
    s = ord(m.group(0))
    return string.uppercase[s >> 4] + string.uppercase[s & 0x0f]

def decode_name(name):
    name_length = ord(name[0])
    assert name_length == 32

    decoded_name = re.sub('..', _do_first_level_decoding, name[1:33])
    if name[33] == '\0':
        return 34, decoded_name, ''
    else:
        decoded_domain = ''
        offset = 34
        while 1:
            domain_length = ord(name[offset])
            if domain_length == 0:
                break
            decoded_domain = '.' + name[offset:offset + domain_length]
            offset += domain_length
        return offset + 1, decoded_name, decoded_domain

def _do_first_level_decoding(m):
    s = m.group(0)
    return chr(((ord(s[0]) - ord('A')) << 4) | (ord(s[1]) - ord('A')))



class NetBIOSSessionPacket:
    def __init__(self, data = 0):
        self.type = 0x0 
        self.flags = 0x0
        self.length = 0x0
        if data == 0:
            self._trailer = ''
        else:
            try:
                self.type = ord(data[0])
                if self.type == NETBIOS_SESSION_MESSAGE:
                    self.length = ord(data[1]) << 16 | (unpack('!H', data[2:4])[0])
                else:
                    self.flags = ord(data[1])
                    self.length = unpack('!H', data[2:4])[0]

                self._trailer = data[4:]
            except:
                raise NetBIOSError( 'Wrong packet format ' )

    def set_type(self, type):
        self.type = type
    def get_type(self):
        return self.type
    def rawData(self):
        if self.type == NETBIOS_SESSION_MESSAGE:
            data = pack('!BBH',self.type,self.length >> 16,self.length & 0xFFFF) + self._trailer
        else:
            data = pack('!BBH',self.type,self.flags,self.length) + self._trailer
        return data
    def set_trailer(self,data):
        self._trailer = data
        self.length = len(data)
    def get_length(self):
        return self.length
    def get_trailer(self):
        return self._trailer
        
class NetBIOSSession:
    def __init__(self, myname, remote_name, remote_host, remote_type = TYPE_SERVER, sess_port = NETBIOS_SESSION_PORT, timeout = None, local_type = TYPE_WORKSTATION, sock = None):
        if len(myname) > 15:
            self.__myname = string.upper(myname[:15])
        else:
            self.__myname = string.upper(myname)
        self.__local_type = local_type

        assert remote_name
        # if destination port SMB_SESSION_PORT and remote name *SMBSERVER, we're changing it to its IP address
        # helping solving the client mistake ;)
        if remote_name == '*SMBSERVER' and sess_port == SMB_SESSION_PORT:
            remote_name = remote_host 
        # If remote name is *SMBSERVER let's try to query its name.. if can't be guessed, continue and hope for the best
        if remote_name == '*SMBSERVER':
            nb = NetBIOS()
            
            try:
                res = nb.getnetbiosname(remote_host)
            except:
                res = None
                pass 
            
            if res is not None:
                remote_name = res

        if len(remote_name) > 15:
            self.__remote_name = string.upper(remote_name[:15])
        else:
            self.__remote_name = string.upper(remote_name)
        self.__remote_type = remote_type

        self.__remote_host = remote_host

        if sock is not None:
            # We are acting as a server
            self._sock = sock
        else:
            self._sock = self._setup_connection((remote_host, sess_port))

        if sess_port == NETBIOS_SESSION_PORT:
            self._request_session(remote_type, local_type, timeout)

    def get_myname(self):
        return self.__myname

    def get_mytype(self):
        return self.__local_type

    def get_remote_host(self):
        return self.__remote_host

    def get_remote_name(self):
        return self.__remote_name

    def get_remote_type(self):
        return self.__remote_type

    def close(self):
        self._sock.close()

    def get_socket(self):
        return self._sock

class NetBIOSUDPSessionPacket(Structure):
    TYPE_DIRECT_UNIQUE = 16
    TYPE_DIRECT_GROUP  = 17

    FLAGS_MORE_FRAGMENTS = 1
    FLAGS_FIRST_FRAGMENT = 2
    FLAGS_B_NODE         = 0

    structure = (
        ('Type','B=16'),    # Direct Unique Datagram
        ('Flags','B=2'),    # FLAGS_FIRST_FRAGMENT
        ('ID','<H'),
        ('_SourceIP','>L'),
        ('SourceIP','"'),
        ('SourcePort','>H=138'),
        ('DataLegth','>H-Data'),
        ('Offset','>H=0'),
        ('SourceName','z'),
        ('DestinationName','z'),
        ('Data',':'),
    )

    def getData(self):
        addr = self['SourceIP'].split('.')
        addr = [int(x) for x in addr]
        addr = (((addr[0] << 8) + addr[1] << 8) + addr[2] << 8) + addr[3]
        self['_SourceIP'] = addr
        return Structure.getData(self)

    def get_trailer(self):
        return self['Data']

class NetBIOSUDPSession(NetBIOSSession):
    def _setup_connection(self, peer):
        af, socktype, proto, canonname, sa = socket.getaddrinfo(peer[0], peer[1], 0, socket.SOCK_DGRAM)[0]
        sock = socket.socket(af, socktype, proto)
        sock.connect(sa)

        sock = socket.socket(af, socktype, proto)
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        sock.bind((INADDR_ANY, 138))
        self.peer = peer
        return sock

    def _request_session(self, remote_type, local_type, timeout = None):
        pass

    def next_id(self):
        if hasattr(self, '__dgram_id'):
            answer = self.__dgram_id
        else:
            self.__dgram_id = randint(1,65535)
            answer = self.__dgram_id
        self.__dgram_id += 1
        return answer

    def send_packet(self, data):
        # Yes... I know...
        self._sock.connect(self.peer)

        p = NetBIOSUDPSessionPacket()
        p['ID'] = self.next_id()
        p['SourceIP'] = self._sock.getsockname()[0]
        p['SourceName'] = encode_name(self.get_myname(), self.get_mytype(), '')[:-1]
        p['DestinationName'] = encode_name(self.get_remote_name(), self.get_remote_type(), '')[:-1]
        p['Data'] = data

        self._sock.sendto(str(p), self.peer)
        self._sock.close()

        self._sock = self._setup_connection(self.peer)

    def recv_packet(self, timeout = None):
        # The next loop is a workaround for a bigger problem:
        # When data reaches higher layers, the lower headers are lost,
        # and with them, for example, the source IP. Hence, SMB users
        # can't know where packets are comming from... we need a better
        # solution, right now, we will filter everything except packets
        # coming from the remote_host specified in __init__()

        while 1:
            data, peer = self._sock.recvfrom(8192)
#            print "peer: %r  self.peer: %r" % (peer, self.peer)
            if peer == self.peer: break

        return NetBIOSUDPSessionPacket(data)

class NetBIOSTCPSession(NetBIOSSession):
    def __init__(self, myname, remote_name, remote_host, remote_type = TYPE_SERVER, sess_port = NETBIOS_SESSION_PORT, timeout = None, local_type = TYPE_WORKSTATION, sock = None, select_poll = False):
        self.__select_poll = select_poll
        if self.__select_poll:
            self.read_function = self.polling_read
        else:
            self.read_function = self.non_polling_read
        NetBIOSSession.__init__(self, myname, remote_name, remote_host, remote_type = remote_type, sess_port = sess_port, timeout = timeout, local_type = local_type, sock=sock)                


    def _setup_connection(self, peer):
        try:
            af, socktype, proto, canonname, sa = socket.getaddrinfo(peer[0], peer[1], 0, socket.SOCK_STREAM)[0]
            sock = socket.socket(af, socktype, proto)
            sock.connect(sa)
        except socket.error, e:
            raise socket.error("Connection error (%s:%s)" % (peer[0], peer[1]), e)
        return sock

    def send_packet(self, data):
        p = NetBIOSSessionPacket()
        p.set_type(NETBIOS_SESSION_MESSAGE)
        p.set_trailer(data)
        self._sock.send(p.rawData())

    def recv_packet(self, timeout = None):
        data = self.__read(timeout)
        return NetBIOSSessionPacket(data)

    def _request_session(self, remote_type, local_type, timeout = None):
        p = NetBIOSSessionPacket()
        remote_name = encode_name(self.get_remote_name(), remote_type, '')
        myname = encode_name(self.get_myname(), local_type, '')
        p.set_type(NETBIOS_SESSION_REQUEST)
        p.set_trailer(remote_name + myname)

        self._sock.send(p.rawData())
        while 1:
            p = self.recv_packet(timeout)
            if p.get_type() == NETBIOS_SESSION_NEGATIVE_RESPONSE:
                raise NetBIOSError, ( 'Cannot request session', ERRCLASS_SESSION, ord(p.get_trailer()[0]) )
            elif p.get_type() == NETBIOS_SESSION_POSITIVE_RESPONSE:
                break
            else:
                # Ignore all other messages, most probably keepalive messages
                pass

    def polling_read(self, read_length, timeout):
        data = ''
        if timeout is None:
            timeout = 3600

        time_left = timeout
        CHUNK_TIME = 0.025
        bytes_left = read_length

        while bytes_left > 0:
            try:
                ready, _, _ = select.select([self._sock.fileno() ], [ ], [ ], 0)
                
                if not ready:
                    if time_left <= 0:
                        raise NetBIOSTimeout
                    else:
                        time.sleep(CHUNK_TIME)
                        time_left -= CHUNK_TIME
                        continue

                received = self._sock.recv(bytes_left)
                if len(received) == 0:
                    raise NetBIOSError, ( 'Error while reading from remote', ERRCLASS_OS, None)

                data = data + received
                bytes_left = read_length - len(data)
            except select.error, ex:
                if ex[0] != errno.EINTR and ex[0] != errno.EAGAIN:
                    raise NetBIOSError, ( 'Error occurs while reading from remote', ERRCLASS_OS, ex[0] )

        return data

    def non_polling_read(self, read_length, timeout):
        data = ''
        bytes_left = read_length

        while bytes_left > 0:
            try:
                ready, _, _ = select.select([self._sock.fileno() ], [ ], [ ], timeout)

                if not ready:
                        raise NetBIOSTimeout

                received = self._sock.recv(bytes_left)
                if len(received) == 0:
                    raise NetBIOSError, ( 'Error while reading from remote', ERRCLASS_OS, None)

                data = data + received
                bytes_left = read_length - len(data)
            except select.error, ex:
                if ex[0] != errno.EINTR and ex[0] != errno.EAGAIN:
                    raise NetBIOSError, ( 'Error occurs while reading from remote', ERRCLASS_OS, ex[0] )

        return data

    def __read(self, timeout = None):
        data = self.read_function(4, timeout)
        type, flags, length = unpack('>ccH', data)
        if ord(type) == NETBIOS_SESSION_MESSAGE:
            length |= ord(flags) << 16
        else:
            if ord(flags) & 0x01:
                length |= 0x10000
        data2 = self.read_function(length, timeout)

        return data + data2

ERRCLASS_QUERY = 0x00
ERRCLASS_SESSION = 0xf0
ERRCLASS_OS = 0xff

QUERY_ERRORS = { 0x01: 'Request format error. Please file a bug report.',
                 0x02: 'Internal server error',
                 0x03: 'Name does not exist',
                 0x04: 'Unsupported request',
                 0x05: 'Request refused'
                 }

SESSION_ERRORS = { 0x80: 'Not listening on called name',
                   0x81: 'Not listening for calling name',
                   0x82: 'Called name not present',
                   0x83: 'Sufficient resources',
                   0x8f: 'Unspecified error'
                   }

def main():
    def get_netbios_host_by_name(name):
        n = NetBIOS()
        n.set_broadcastaddr('255.255.255.255') # To avoid use "<broadcast>" in socket
        for qtype in (TYPE_WORKSTATION, TYPE_CLIENT, TYPE_SERVER, TYPE_DOMAIN_MASTER, TYPE_DOMAIN_CONTROLLER):
            try:
                addrs = n.gethostbyname(name, qtype = qtype).get_addr_entries()
            except NetBIOSTimeout:
                continue
            else:
                return addrs
        raise Exception("Host not found")
                
    
    n = get_netbios_host_by_name("some-host")
    print n

if __name__ == '__main__':
    main()