summaryrefslogtreecommitdiffstats
path: root/nselib/ipOps.lua
blob: aa45dac7dbe5aead21e218b2cdce0a44a2aeb933 (plain)
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
---
-- Utility functions for manipulating and comparing IP addresses.
--
-- @copyright Same as Nmap--See https://nmap.org/book/man-legal.html

local math = require "math"
local stdnse = require "stdnse"
local string = require "string"
local stringaux = require "stringaux"
local table = require "table"
local type     = type
local ipairs   = ipairs
local tonumber = tonumber
local unittest = require "unittest"


_ENV = stdnse.module("ipOps", stdnse.seeall)

local pack = string.pack
local unpack = string.unpack

---
-- Checks to see if the supplied IP address is part of a non-routable
-- address space.
--
-- The non-Internet-routable address spaces known to this function are
-- * IPv4 Loopback (RFC3330)
-- * IPv4 Private Use (RFC1918)
-- * IPv4 Link Local (RFC3330)
-- * IPv4 IETF Protocol Assignments (RFC 5736)
-- * IPv4 TEST-NET-1, TEST-NET-2, TEST-NET-3 (RFC 5737)
-- * IPv4 Network Interconnect Device Benchmark Testing (RFC 2544)
-- * IPv4 Reserved for Future Use (RFC 1112, Section 4)
-- * IPv4 Multicast Local Network Control Block (RFC 3171, Section 3)
-- * IPv6 Unspecified and Loopback (RFC3513)
-- * IPv6 Site-Local (RFC3513, deprecated in RFC3879)
-- * IPv6 Unique Local Unicast (RFC4193)
-- * IPv6 Link Local Unicast (RFC4291)
-- @param ip  String representing an IPv4 or IPv6 address.  Shortened notation
-- is permitted.
-- @usage
-- local is_private = ipOps.isPrivate( "192.168.1.1" )
-- @return True or false (or <code>nil</code> in case of an error).
-- @return String error message in case of an error or
--         String non-routable address containing the supplied IP address.
isPrivate = function( ip )
  local err

  ip, err = expand_ip( ip )
  if err then return nil, err end

  if ip:match( ":" ) then

    local is_private
    local ipv6_private = { "::/127", "FC00::/7", "FE80::/10", "FEC0::/10" }

    for _, range in ipairs( ipv6_private ) do
      is_private, err = ip_in_range( ip, range )
      if is_private == true then
        return true, range
      end
      if err then
        return nil, err
      end
    end

  elseif ip:sub(1,3) == '10.' then

    return true, '10/8'

  elseif ip:sub(1,4) == '127.' then

    return true, '127/8'

  elseif ip:sub(1,8) == '169.254.' then

    return true, '169.254/16'

  elseif ip:sub(1,4) == '172.' then

    local p, e = ip_in_range(ip, '172.16/12')
    if p == true then
      return true, '172.16/12'
    else
      return p, e
    end

  elseif ip:sub(1,4) == '192.' then

    if ip:sub(5,8) == '168.' then
      return true, '192.168/16'
    elseif ip:match('^192%.[0][0]?[0]?%.[0][0]?[0]?%.') then
      return true, '192.0.0/24'
    elseif ip:match('^192%.[0][0]?[0]?%.[0]?[0]?2') then
      return true, '192.0.2/24'
    end

  elseif ip:sub(1,4) == '198.' then

    if ip:match('^198%.[0]?18%.') or ip:match('^198%.[0]?19%.') then
      return true, '198.18/15'
    elseif ip:match('^198%.[0]?51%.100%.') then
      return true, '198.51.100/24'
    end

  elseif ip:match('^203%.[0][0]?[0]?%.113%.') then

    return true, '203.0.113/24'

  elseif ip:match('^224%.[0][0]?[0]?%.[0][0]?[0]?%.') then

    return true, '224.0.0/24'

  elseif ip:match('^24[0-9]%.') or ip:match('^25[0-5]%.') then

    return true, '240.0.0/4'

  end

  return false, nil

end



---
-- Converts the supplied IPv4 address into a DWORD value.
--
-- For example, the address a.b.c.d becomes (((a*256+b)*256+c)*256+d).
--
-- Note: IPv6 addresses are not supported. Currently, numbers in NSE are
-- limited to 10^14, and consequently not all IPv6 addresses can be
-- represented. Consider using <code>ip_to_str</code> for IPv6 addresses.
-- @param ip  String representing an IPv4 address.  Shortened notation is
-- permitted.
-- @usage
-- local dword = ipOps.todword( "73.150.2.210" )
-- @return Number corresponding to the supplied IP address (or <code>nil</code>
-- in case of an error).
-- @return String error message in case of an error.
todword = function( ip )

  if type( ip ) ~= "string" or ip:match( ":" ) then
    return nil, "Error in ipOps.todword: Expected IPv4 address."
  end

  local n, ret, err = {}
  n, err = get_parts_as_number( ip )
  if err then return nil, err end

  ret = (((n[1]*256+n[2]))*256+n[3])*256+n[4]

  return ret

end

---
-- Converts the supplied IPv4 address from a DWORD value into a dotted string.
--
-- For example, the address (((a*256+b)*256+c)*256+d) becomes a.b.c.d.
--
--@param ip DWORD representing an IPv4 address.
--@return The string representing the address.
fromdword = function( ip )
  if type( ip ) ~= "number" then
    stdnse.debug1("Error in ipOps.fromdword: Expected 32-bit number.")
    return nil
  end
  return string.format("%d.%d.%d.%d", unpack("BBBB", pack(">I4", ip)))
end

---
-- Separates the supplied IP address into its constituent parts and
-- returns them as a table of numbers.
--
-- For example, the address 139.104.32.123 becomes { 139, 104, 32, 123 }.
-- @usage
-- local a, b, c, d;
-- local t, err = ipOps.get_parts_as_number( "139.104.32.123" )
-- if t then a, b, c, d = table.unpack( t ) end
-- @param ip  String representing an IPv4 or IPv6 address.  Shortened notation
-- is permitted.
-- @return   Array of numbers for each part of the supplied IP address (or
-- <code>nil</code> in case of an error).
-- @return String error message in case of an error.
get_parts_as_number = function( ip )
  local err

  ip, err = expand_ip( ip )
  if err then return nil, err end

  local pattern, base
  if ip:match( ":" ) then
    pattern = "%x+"
    base = 16
  else
    pattern = "%d+"
    base = 10
  end
  local t = {}
  for part in string.gmatch(ip, pattern) do
    t[#t+1] = tonumber( part, base )
  end

  return t

end



---
-- Compares two IP addresses.
--
-- When comparing addresses from different families,
-- IPv4 addresses will sort before IPv6 addresses.
-- @param left String representing an IPv4 or IPv6 address.  Shortened
--             notation is permitted.
-- @param op A comparison operator which may be one of the following strings:
--           <code>"eq"</code>, <code>"ge"</code>, <code>"le"</code>,
--           <code>"gt"</code> or <code>"lt"</code> (respectively ==, >=, <=,
--           >, <).
-- @param right String representing an IPv4 or IPv6 address.  Shortened
--              notation is permitted.
-- @usage
-- if ipOps.compare_ip( "2001::DEAD:0:0:0", "eq", "2001:0:0:0:DEAD::" ) then
--   ...
-- end
-- @return True or false (or <code>nil</code> in case of an error).
-- @return String error message in case of an error.
compare_ip = function( left, op, right )

  if type( left ) ~= "string" or type( right ) ~= "string" then
    return nil, "Error in ipOps.compare_ip: Expected IP address as a string."
  end

  local err ={}
  left, err[#err+1] = ip_to_str( left )
  right, err[#err+1] = ip_to_str( right )
  if #err > 0 then
    return nil, table.concat( err, " " )
  end

  -- by prepending the length, IPv4 (length 4) sorts before IPv6 (length 16)
  left = pack("s1", left)
  right = pack("s1", right)

  if ( op == "eq" ) then
    return ( left == right )
  elseif ( op == "ne" ) then
    return ( left ~= right )
  elseif ( op == "le" ) then
    return ( left <= right )
  elseif ( op == "ge" ) then
    return ( left >= right )
  elseif ( op == "lt" ) then
    return ( left < right )
  elseif ( op == "gt" ) then
    return ( left > right )
  end

  return nil, "Error in ipOps.compare_ip: Invalid Operator."
end

--- Sorts a table of IP addresses
--
-- An in-place sort using <code>table.sort</code> to sort by IP address.
-- Sorting non-IP addresses is likely to result in a bad sort and possibly an infinite loop.
--
-- @param ips The table of IP addresses to sort
-- @param op The comparison operation to use. Default: "lt" (ascending)
ip_sort = function (ips, op)
  op = op or "lt"
  return table.sort(ips, function(a, b) return compare_ip(a, op, b) end)
end

---
-- Checks whether the supplied IP address is within the supplied range of IP
-- addresses.
--
-- The address and the range must both belong to the same address family.
-- @param ip     String representing an IPv4 or IPv6 address.  Shortened
-- notation is permitted.
-- @param range  String representing a range of IPv4 or IPv6 addresses in
-- first-last or CIDR notation (e.g.
-- <code>"192.168.1.1 - 192.168.255.255"</code> or
-- <code>"2001:0A00::/23"</code>).
-- @usage
-- if ipOps.ip_in_range( "192.168.1.1", "192/8" ) then ... end
-- @return True or false (or <code>nil</code> in case of an error).
-- @return String error message in case of an error.
ip_in_range = function( ip, range )

  local first, last, err = get_ips_from_range( range )
  if err then return nil, err end
  ip, err = expand_ip( ip )
  if err then return nil, err end
  if ( ip:match( ":" ) and not first:match( ":" ) ) or ( not ip:match( ":" ) and first:match( ":" ) ) then
    return nil, "Error in ipOps.ip_in_range: IP address is of a different address family to Range."
  end

  err = {}
  local ip_ge_first, ip_le_last
  ip_ge_first, err[#err+1] = compare_ip( ip, "ge", first )
  ip_le_last, err[#err+1] = compare_ip( ip, "le", last )
  if #err > 0 then
    return nil, table.concat( err, " " )
  end

  if ip_ge_first and ip_le_last then
    return true
  else
    return false
  end

end



---
-- Expands an IP address supplied in shortened notation.
-- Serves also to check the well-formedness of an IP address.
--
-- Note: IPv4in6 notated addresses will be returned in pure IPv6 notation unless
-- the IPv4 portion is shortened and does not contain a dot, in which case the
-- address will be treated as IPv6.
-- @param ip  String representing an IPv4 or IPv6 address in shortened or full notation.
-- @param family String representing the address family to expand to. Only
-- affects IPv4 addresses when "inet6" is provided, causing the function to
-- return an IPv4-mapped IPv6 address.
-- @usage
-- local ip = ipOps.expand_ip( "2001::" )
-- @return    String representing a fully expanded IPv4 or IPv6 address (or
-- <code>nil</code> in case of an error).
-- @return String error message in case of an error.
expand_ip = function( ip, family )
  local err

  if type( ip ) ~= "string" or ip == "" then
    return nil, "Error in ipOps.expand_ip: Expected IP address as a string."
  end

  local err4 = "Error in ipOps.expand_ip: An address assumed to be IPv4 was malformed."

  if not ip:match( ":" ) then
    -- ipv4: missing octets should be "0" appended
    if ip:match( "[^%.0-9]" ) then
      return nil, err4
    end
    local octets = {}
    for octet in string.gmatch( ip, "%d+" ) do
      if tonumber( octet, 10 ) > 255 then return nil, err4 end
      octets[#octets+1] = octet
    end
    if #octets > 4 then return nil, err4 end
    while #octets < 4 do
      octets[#octets+1] = "0"
    end
    if family == "inet6" then
      return ( table.concat( { 0,0,0,0,0,"ffff",
        stdnse.tohex( 256*octets[1]+octets[2] ),
        stdnse.tohex( 256*octets[3]+octets[4] )
        }, ":" ) )
    else
      return ( table.concat( octets, "." ) )
    end
  end

  if family ~= nil and family ~= "inet6" then
    return nil, "Error in ipOps.expand_ip: Cannot convert IPv6 address to IPv4"
  end

  if ip:match( "[^%.:%x]" ) then
    return nil, ( err4:gsub( "IPv4", "IPv6" ) )
  end

  -- preserve ::
  ip = string.gsub(ip, "::", ":z:")

  -- get a table of each hexadectet
  local hexadectets = {}
  for hdt in string.gmatch( ip, "[%.z%x]+" ) do
    hexadectets[#hexadectets+1] = hdt
  end

  -- deal with IPv4in6 (last hexadectet only)
  local t = {}
  if hexadectets[#hexadectets]:match( "[%.]+" ) then
    hexadectets[#hexadectets], err = expand_ip( hexadectets[#hexadectets] )
    if err then return nil, ( err:gsub( "IPv4", "IPv4in6" ) ) end
    t = stringaux.strsplit( "[%.]+", hexadectets[#hexadectets] )
    for i, v in ipairs( t ) do
      t[i] = tonumber( v, 10 )
    end
    hexadectets[#hexadectets] = stdnse.tohex( 256*t[1]+t[2] )
    hexadectets[#hexadectets+1] = stdnse.tohex( 256*t[3]+t[4] )
  end

  -- deal with :: and check for invalid address
  local z_done = false
  for index, value in ipairs( hexadectets ) do
    if value:match( "[%.]+" ) then
      -- shouldn't have dots at this point
      return nil, ( err4:gsub( "IPv4", "IPv6" ) )
    elseif value == "z" and z_done then
      -- can't have more than one ::
      return nil, ( err4:gsub( "IPv4", "IPv6" ) )
    elseif value == "z" and not z_done then
      z_done = true
      hexadectets[index] = "0"
      local bound = 8 - #hexadectets
      for i = 1, bound, 1 do
        table.insert( hexadectets, index+i, "0" )
      end
    elseif tonumber( value, 16 ) > 65535 then
      -- more than FFFF!
      return nil, ( err4:gsub( "IPv4", "IPv6" ) )
    end
  end

  -- make sure we have exactly 8 hexadectets
  if #hexadectets > 8 then return nil, ( err4:gsub( "IPv4", "IPv6" ) ) end
  while #hexadectets < 8 do
    hexadectets[#hexadectets+1] = "0"
  end

  return ( table.concat( hexadectets, ":" ) )

end



---
-- Returns the first and last IP addresses in the supplied range of addresses.
-- @param range  String representing a range of IPv4 or IPv6 addresses in either
-- CIDR or first-last notation.
-- @usage
-- first, last = ipOps.get_ips_from_range( "192.168.0.0/16" )
-- @return       String representing the first address in the supplied range (or
-- <code>nil</code> in case of an error).
-- @return       String representing the last address in the supplied range (or
-- <code>nil</code> in case of an error).
-- @return       String error message in case of an error.
get_ips_from_range = function( range )

  if type( range ) ~= "string" then
    return nil, nil, "Error in ipOps.get_ips_from_range: Expected a range as a string."
  end

  local ip, prefix = range:match("^%s*([%x:.]+)/(%d+)%s*$")
  if ip then
    return get_first_last_ip(ip, prefix)
  end
  local first, last = range:match("^%s*([%x:.]+)%s*%-%s*([%x:.]+)%s*$")
  if not first then
    return nil, nil, "Error in ipOps.get_ips_from_range: The range supplied could not be interpreted."
  end

  local err
  first, err = expand_ip(first)
  if not err then
    last, err = expand_ip(last)
  end
  if not err then
    local af = function (ip) return ip:find(":") and 6 or 4 end
    if af(first) ~= af(last) then
      err = "Error in ipOps.get_ips_from_range: First IP address is of a different address family to last IP address."
    end
  end
  if err then
      return nil, nil, err
  end
  return first, last
end

---
-- Calculates the first and last IP addresses of a range of addresses,
-- given an IP address in the range and a prefix length for that range
-- @param ip String representing an IPv4 or IPv6 address.  Shortened notation
--           is permitted.
-- @param prefix Number or a string representing a decimal number corresponding
--               to a prefix length.
-- @usage
-- first, last = ipOps.get_first_last_ip( "192.0.0.0", 26)
-- @return String representing the first IP address of the range denoted by
--         the supplied parameters (or <code>nil</code> in case of an error).
-- @return String representing the last IP address of the range denoted by
--         the supplied parameters (or <code>nil</code> in case of an error).
-- @return String error message in case of an error.
get_first_last_ip = function(ip, prefix)
  local err
  ip, err = ip_to_bin(ip)
  if err then return nil, nil, err end

  prefix = tonumber(prefix)
  if not prefix or prefix ~= math.floor(prefix) or prefix < 0 or prefix > #ip then
    return nil, nil, "Error in ipOps.get_first_last_ip: Invalid prefix."
  end

  local net = ip:sub(1, prefix)
  local first = bin_to_ip(net .. ("0"):rep(#ip - prefix))
  local last  = bin_to_ip(net .. ("1"):rep(#ip - prefix))
  return first, last
end

---
-- Calculates the first IP address of a range of addresses given an IP address in
-- the range and prefix length for that range.
-- @param ip String representing an IPv4 or IPv6 address.  Shortened notation
--           is permitted.
-- @param prefix Number or a string representing a decimal number corresponding
--               to a prefix length.
-- @usage
-- first = ipOps.get_first_ip( "192.0.0.0", 26 )
-- @return String representing the first IP address of the range denoted by the
--         supplied parameters (or <code>nil</code> in case of an error).
-- @return String error message in case of an error.
get_first_ip = function(ip, prefix)
  local first, last, err = get_first_last_ip(ip, prefix)
  return first, err
end

---
-- Calculates the last IP address of a range of addresses given an IP address in
-- the range and prefix length for that range.
-- @param ip String representing an IPv4 or IPv6 address.  Shortened notation
--           is permitted.
-- @param prefix Number or a string representing a decimal number corresponding
--               to a prefix length.
-- @usage
-- last = ipOps.get_last_ip( "192.0.0.0", 26 )
-- @return String representing the last IP address of the range denoted by the
--         supplied parameters (or <code>nil</code> in case of an error).
-- @return String error message in case of an error.
get_last_ip = function(ip, prefix)
  local first, last, err = get_first_last_ip(ip, prefix)
  return last, err
end

---
-- Converts an IP address into an opaque string (big-endian)
-- @param ip  String representing an IPv4 or IPv6 address.
-- @param family (optional) Address family to convert to. "ipv6" converts IPv4
-- addresses to IPv4-mapped IPv6.
-- @usage
-- opaque = ipOps.ip_to_str( "192.168.3.4" )
-- @return 4- or 16-byte string representing IP address (or <code>nil</code>
-- in case of an error).
-- @return String error message in case of an error
ip_to_str = function( ip, family )
  local err

  ip, err = expand_ip( ip, family )
  if err then return nil, err end

  local t = {}

  if not ip:match( ":" ) then
    -- ipv4 string
    for octet in string.gmatch( ip, "%d+" ) do
      t[#t+1] = pack("B", octet)
    end
  else
    -- ipv6 string
    for hdt in string.gmatch( ip, "%x+" ) do
      t[#t+1] = pack( ">I2", tonumber(hdt, 16) )
    end
  end


  return table.concat( t )
end

---
-- Converts an opaque string (big-endian) into an IP address
--
-- @param ip Opaque string representing an IP address. If length 4, then IPv4
--           is assumed. If length 16, then IPv6 is assumed.
-- @return IP address in readable notation (or <code>nil</code> in case of an
--         error)
-- @return String error message in case of an error
str_to_ip = function (ip)
  if #ip == 4 then
    return ("%d.%d.%d.%d"):format(unpack("BBBB", ip))
  elseif #ip == 16 then
    local full = ("%x:%x:%x:%x:%x:%x:%x:%x"):format(unpack((">I2"):rep(8), ip))
    full = full:gsub(":[:0]+", "::", 1) -- Collapse the first (should be longest?) series of :0:
    full = full:gsub("^0::", "::", 1) -- handle special case of ::1
    return full
  else
    return nil, "Invalid length"
  end
end

---
-- Converts an IP address into a string representing the address as binary
-- digits.
-- @param ip String representing an IPv4 or IPv6 address.  Shortened notation
--           is permitted.
-- @usage
-- bit_string = ipOps.ip_to_bin( "2001::" )
-- @return String representing the supplied IP address as 32 or 128 binary
--         digits (or <code>nil</code> in case of an error).
-- @return String error message in case of an error.
ip_to_bin = function( ip )
  local err

  ip, err = expand_ip( ip )
  if err then return nil, err end

  local t, mask = {}

  if not ip:match( ":" ) then
    -- ipv4 string
    for octet in string.gmatch( ip, "%d+" ) do
      t[#t+1] = stdnse.tohex( tonumber(octet) )
    end
    mask = "00"
  else
    -- ipv6 string
    for hdt in string.gmatch( ip, "%x+" ) do
      t[#t+1] = hdt
    end
    mask = "0000"
  end

  -- padding
  for i, v in ipairs( t ) do
    t[i] = mask:sub( 1, # mask  - # v  ) .. v
  end

  return hex_to_bin( table.concat( t ) )

end



---
-- Converts a string of binary digits into an IP address.
-- @param binstring  String representing an IP address as 32 or 128 binary
-- digits.
-- @usage
-- ip = ipOps.bin_to_ip( "01111111000000000000000000000001" )
-- @return           String representing an IP address (or <code>nil</code> in
-- case of an error).
-- @return           String error message in case of an error.
bin_to_ip = function( binstring )

  if type( binstring ) ~= "string" or binstring:match( "[^01]+" ) then
    return nil, "Error in ipOps.bin_to_ip: Expected string of binary digits."
  end

  local af
  if # binstring  == 32 then
    af = 4
  elseif # binstring  == 128 then
    af = 6
  else
    return nil, "Error in ipOps.bin_to_ip: Expected exactly 32 or 128 binary digits."
  end

  local t = {}
  if af == 6 then
    local pattern = string.rep( "[01]", 16 )
    for chunk in string.gmatch( binstring, pattern ) do
      t[#t+1] = stdnse.tohex( tonumber( chunk, 2 ) )
    end
    return table.concat( t, ":" )
  end

  if af == 4 then
    local pattern = string.rep( "[01]", 8 )
    for chunk in string.gmatch( binstring, pattern ) do
      t[#t+1] = tonumber( chunk, 2 ) .. ""
    end
    return table.concat( t, "." )
  end

end



local bin_lookup = {
  ["0"]="0000",
  ["1"]="0001",
  ["2"]="0010",
  ["3"]="0011",
  ["4"]="0100",
  ["5"]="0101",
  ["6"]="0110",
  ["7"]="0111",
  ["8"]="1000",
  ["9"]="1001",
  ["a"]="1010",
  ["b"]="1011",
  ["c"]="1100",
  ["d"]="1101",
  ["e"]="1110",
  ["f"]="1111",
}
setmetatable(bin_lookup, {
    __index = function()
      error("Error in ipOps.hex_to_bin: Expected string representing a hexadecimal number.")
    end
  })
---
-- Converts a string of hexadecimal digits into the corresponding string of
-- binary digits.
--
-- Each hex digit results in four bits.
-- @param hex  String representing a hexadecimal number.
-- @usage
-- bin_string = ipOps.hex_to_bin( "F00D" )
-- @return     String representing the supplied number in binary digits (or
-- <code>nil</code> in case of an error).
-- @return     String error message in case of an error.
hex_to_bin = function( hex )
  if type( hex ) ~= "string" then
    return nil, "Error in ipOps.hex_to_bin: Expected string"
  end

  local status, result = pcall( string.gsub, string.lower(hex), ".", bin_lookup)
  if status then
    return result
  end
  return status, result
end

---
-- Convert a CIDR subnet mask to dotted decimal notation.
--
-- @param subnet CIDR string representing the subnet mask.
-- @usage
-- local netmask = ipOps.cidr_to_subnet( "/16" )
-- @return Dotted decimal representation of the suppliet subnet mask (e.g. "255.255.0.0")
cidr_to_subnet = function( subnet )
  local bits = subnet:match("/(%d%d)$")
  if not bits then return nil end
  return fromdword((0xFFFFFFFF >> tonumber(bits)) ~ 0xFFFFFFFF)
end

---
-- Convert a dotted decimal subnet mask to CIDR notation.
--
-- @param subnet Dotted decimal string representing the subnet mask.
-- @usage
-- local cidr = ipOps.subnet_to_cidr( "255.255.0.0" )
-- @return CIDR representation of the supplied subnet mask (e.g. "/16").
subnet_to_cidr = function( subnet )
  local dword, err = todword(subnet)
  if not dword then return nil, err end
  return "/" .. tostring(32 - (math.tointeger(math.log((dword ~ 0xFFFFFFFF) + 1, 2))))
end

--Ignore the rest if we are not testing.
if not unittest.testing() then
  return _ENV
end

test_suite = unittest.TestSuite:new()
test_suite:add_test(unittest.is_true(isPrivate("192.168.123.123")), "192.168.123.123 is private")
test_suite:add_test(unittest.is_false(isPrivate("1.1.1.1")), "1.1.1.1 is not private")
test_suite:add_test(unittest.equal(todword("65.66.67.68"),0x41424344), "todword")
test_suite:add_test(unittest.equal(todword("127.0.0.1"),0x7f000001), "todword")
test_suite:add_test(unittest.equal(fromdword(0xffffffff),"255.255.255.255"), "fromdword")
test_suite:add_test(unittest.equal(fromdword(0x7f000001),"127.0.0.1"), "fromdword")
test_suite:add_test(unittest.equal(str_to_ip("\x01\x02\x03\x04"),"1.2.3.4"), "str_to_ip (ipv4)")
test_suite:add_test(unittest.equal(str_to_ip("\0\x01\xbe\xef\0\0\0\0\0\0\x02\x03\0\0\0\x01"),"1:beef::203:0:1"), "str_to_ip (ipv6)")
test_suite:add_test(unittest.equal(str_to_ip(("\0"):rep(15) .. "\x01"),"::1"), "str_to_ip (ipv6)")
test_suite:add_test(function()
  local parts, err = get_parts_as_number("8.255.0.1")
  if parts == nil then return false, err end
  if parts[1] == 8 and parts[2] == 255 and parts[3] == 0 and parts[4] == 1 then
    return true
  end
  return false, string.format("Expected {8, 255, 0, 1}, got {%d, %d, %d, %d}", table.unpack(parts))
end, "get_parts_as_number")

do
  local low_ip4 = "192.168.1.10"
  local high_ip4 = "192.168.10.1"
  local low_ip6 = "2001::DEAD:0:0:9"
  local high_ip6 = "2001::DEAF:0:0:9"
  for _, op in ipairs({
    {low_ip4, "eq", low_ip4, unittest.is_true, "IPv4"},
    {low_ip6, "eq", low_ip6, unittest.is_true, "IPv6"},
    {high_ip4, "eq", low_ip4, unittest.is_false, "IPv4"},
    {high_ip6, "eq", low_ip6, unittest.is_false, "IPv6"},
    {low_ip4, "eq", low_ip6, unittest.is_false, "mixed"},
    {low_ip4, "ne", low_ip4, unittest.is_false, "IPv4"},
    {low_ip6, "ne", low_ip6, unittest.is_false, "IPv6"},
    {high_ip4, "ne", low_ip4, unittest.is_true, "IPv4"},
    {high_ip6, "ne", low_ip6, unittest.is_true, "IPv6"},
    {low_ip4, "ne", low_ip6, unittest.is_true, "mixed"},
    {low_ip4, "ge", low_ip4, unittest.is_true, "IPv4, equal"},
    {low_ip6, "ge", low_ip6, unittest.is_true, "IPv6, equal"},
    {high_ip4, "ge", low_ip4, unittest.is_true, "IPv4"},
    {high_ip6, "ge", low_ip6, unittest.is_true, "IPv6"},
    {low_ip4, "ge", high_ip4, unittest.is_false, "IPv4"},
    {low_ip6, "ge", high_ip6, unittest.is_false, "IPv6"},
    {low_ip6, "ge", low_ip4, unittest.is_true, "mixed"},
    {low_ip4, "ge", low_ip6, unittest.is_false, "mixed"},
    {low_ip4, "le", low_ip4, unittest.is_true, "IPv4, equal"},
    {low_ip6, "le", low_ip6, unittest.is_true, "IPv6, equal"},
    {high_ip4, "le", low_ip4, unittest.is_false, "IPv4"},
    {high_ip6, "le", low_ip6, unittest.is_false, "IPv6"},
    {low_ip4, "le", high_ip4, unittest.is_true, "IPv4"},
    {low_ip6, "le", high_ip6, unittest.is_true, "IPv6"},
    {low_ip6, "le", low_ip4, unittest.is_false, "mixed"},
    {low_ip4, "le", low_ip6, unittest.is_true, "mixed"},
    {low_ip4, "gt", low_ip4, unittest.is_false, "IPv4, equal"},
    {low_ip6, "gt", low_ip6, unittest.is_false, "IPv6, equal"},
    {high_ip4, "gt", low_ip4, unittest.is_true, "IPv4"},
    {high_ip6, "gt", low_ip6, unittest.is_true, "IPv6"},
    {low_ip4, "gt", high_ip4, unittest.is_false, "IPv4"},
    {low_ip6, "gt", high_ip6, unittest.is_false, "IPv6"},
    {low_ip6, "gt", low_ip4, unittest.is_true, "mixed"},
    {low_ip4, "gt", low_ip6, unittest.is_false, "mixed"},
    {low_ip4, "lt", low_ip4, unittest.is_false, "IPv4, equal"},
    {low_ip6, "lt", low_ip6, unittest.is_false, "IPv6, equal"},
    {high_ip4, "lt", low_ip4, unittest.is_false, "IPv4"},
    {high_ip6, "lt", low_ip6, unittest.is_false, "IPv6"},
    {low_ip4, "lt", high_ip4, unittest.is_true, "IPv4"},
    {low_ip6, "lt", high_ip6, unittest.is_true, "IPv6"},
    {low_ip6, "lt", low_ip4, unittest.is_false, "mixed"},
    {low_ip4, "lt", low_ip6, unittest.is_true, "mixed"},
    }) do
    test_suite:add_test(op[4](compare_ip(op[1], op[2], op[3])),
      string.format("compare_ip(%s, %s, %s) (%s)", op[1], op[2], op[3], op[5]))
  end
end

do
  for _, h in ipairs({
      {"a", "1010"},
      {"aA", "10101010"},
      {"12", "00010010"},
      {"54321", "01010100001100100001"},
      {"123error", false},
      {"", ""},
      {"bad 123", false},
    }) do
    test_suite:add_test(unittest.equal(hex_to_bin(h[1]), h[2]))
  end
end

do
  for _, op in ipairs({
    {"192.168.13.1", "192/8", unittest.is_true, "IPv4 CIDR"},
    {"193.168.13.1", "192/8", unittest.is_false, "IPv4 CIDR"},
    {"192.168.13.0", "192.168.13.128/24", unittest.is_true, "IPv4 CIDR"},
    {"193.168.13.0", "192.168.13.128/24", unittest.is_false, "IPv4 CIDR"},
    {"2001:db8::9", "2001:db8/32", unittest.is_true, "IPv6 CIDR"},
    {"2001:db7::9", "2001:db8/32", unittest.is_false, "IPv6 CIDR"},
    {"2001:db8::9", "2001:db8::1:0/32", unittest.is_true, "IPv6 CIDR"},
    {"2001:db7::9", "2001:db8::1:0/32", unittest.is_false, "IPv6 CIDR"},
    {"192.168.13.1", "192.168.10.33-192.168.80.80", unittest.is_true, "IPv4 range"},
    {"193.168.13.1", "192.168.1.1 - 192.168.5.0", unittest.is_false, "IPv4 range"},
    {"2001:db8::9", "2001:db8::1-2001:db8:1::1", unittest.is_true, "IPv6 range"},
    {"2001:db8::9", "2001:db8:10::1-2001:db8:11::1", unittest.is_false, "IPv6 range"},
    {"193.168.1.1", "192.168.1.1 - 2001:db8::1", unittest.is_nil, "mixed"},
    {"2001:db8::1", "192.168.1.1 - 2001:db8::1", unittest.is_nil, "mixed"},
    }) do
    test_suite:add_test(op[3](ip_in_range(op[1], op[2])),
      string.format("ip_in_range(%s, %s) (%s)", op[1], op[2], op[4]))
  end
end

do
  for _, op in ipairs({
    {"192.168", nil, "192.168.0.0", "IPv4 trunc"},
    {"192.0.2.3", nil, "192.0.2.3", "IPv4"},
    {"192.168", "inet6", "0:0:0:0:0:ffff:c0a8:0", "IPv4 trunc to IPv6"},
    {"2001:db8::9", nil, "2001:db8:0:0:0:0:0:9", "IPv6"},
    {"::ffff:192.0.2.128", "inet6", "0:0:0:0:0:ffff:c000:280", "IPv4-mapped to IPv6"},
    -- TODO: Perhaps we should support extracting IPv4 from IPv4-mapped addresses?
    --{"::ffff:192.0.2.128", "inet4", "192.0.2.128", "IPv4-mapped to IPv4"},
    --{"::ffff:c000:0280", "inet4", "192.0.2.128", "IPv4-mapped to IPv4"},
    }) do
    test_suite:add_test(unittest.equal(expand_ip(op[1], op[2]), op[3]),
      string.format("expand_ip(%s, %s) (%s)", op[1], op[2], op[4]))
  end
  test_suite:add_test(unittest.is_nil(expand_ip("2001:db8::1", "ipv4")),
      "IPv6 to IPv4")
end
test_suite:add_test(unittest.equal(cidr_to_subnet("/16"), "255.255.0.0"), "cidr_to_subnet")
test_suite:add_test(unittest.equal(subnet_to_cidr("255.255.0.0"), "/16"), "subnet_to_cidr")

return _ENV;