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
|
/*-
* Written by Atsushi Murai <amurai@spec.co.jp>
* Copyright (c) 1998, System Planning and Engineering Co.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* TODO:
* oClean up.
* oConsidering for word alignment for other platform.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
alias_nbt.c performs special processing for NetBios over TCP/IP
sessions by UDP.
Initial version: May, 1998 (Atsushi Murai <amurai@spec.co.jp>)
See HISTORY file for record of revisions.
*/
/* Includes */
#ifdef _KERNEL
#include <sys/param.h>
#include <sys/ctype.h>
#include <sys/libkern.h>
#else
#include <sys/types.h>
#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <arpa/inet.h>
#endif
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <netinet/tcp.h>
#ifdef _KERNEL
#include <netinet/libalias/alias_local.h>
#else
#include "alias_local.h"
#endif
typedef struct {
struct in_addr oldaddr;
u_short oldport;
struct in_addr newaddr;
u_short newport;
u_short *uh_sum;
} NBTArguments;
typedef struct {
unsigned char type;
unsigned char flags;
u_short id;
struct in_addr source_ip;
u_short source_port;
u_short len;
u_short offset;
} NbtDataHeader;
#define OpQuery 0
#define OpUnknown 4
#define OpRegist 5
#define OpRelease 6
#define OpWACK 7
#define OpRefresh 8
typedef struct {
u_short nametrid;
u_short dir: 1, opcode:4, nmflags:7, rcode:4;
u_short qdcount;
u_short ancount;
u_short nscount;
u_short arcount;
} NbtNSHeader;
#define FMT_ERR 0x1
#define SRV_ERR 0x2
#define IMP_ERR 0x4
#define RFS_ERR 0x5
#define ACT_ERR 0x6
#define CFT_ERR 0x7
#ifdef DEBUG
static void
PrintRcode(u_char rcode)
{
switch (rcode) {
case FMT_ERR:
printf("\nFormat Error.");
case SRV_ERR:
printf("\nSever failure.");
case IMP_ERR:
printf("\nUnsupported request error.\n");
case RFS_ERR:
printf("\nRefused error.\n");
case ACT_ERR:
printf("\nActive error.\n");
case CFT_ERR:
printf("\nName in conflict error.\n");
default:
printf("\n?%c?=%0x\n", '?', rcode);
}
}
#endif
/* Handling Name field */
static u_char *
AliasHandleName(u_char * p, char *pmax)
{
u_char *s;
u_char c;
int compress;
/* Following length field */
if (p == NULL || (char *)p >= pmax)
return (NULL);
if (*p & 0xc0) {
p = p + 2;
if ((char *)p > pmax)
return (NULL);
return ((u_char *) p);
}
while ((*p & 0x3f) != 0x00) {
s = p + 1;
if (*p == 0x20)
compress = 1;
else
compress = 0;
/* Get next length field */
p = (u_char *) (p + (*p & 0x3f) + 1);
if ((char *)p > pmax) {
p = NULL;
break;
}
#ifdef DEBUG
printf(":");
#endif
while (s < p) {
if (compress == 1) {
c = (u_char) (((((*s & 0x0f) << 4) | (*(s + 1) & 0x0f)) - 0x11));
#ifdef DEBUG
if (isprint(c))
printf("%c", c);
else
printf("<0x%02x>", c);
#endif
s += 2;
} else {
#ifdef DEBUG
printf("%c", *s);
#endif
s++;
}
}
#ifdef DEBUG
printf(":");
fflush(stdout);
#endif
}
/* Set up to out of Name field */
if (p == NULL || (char *)p >= pmax)
p = NULL;
else
p++;
return ((u_char *) p);
}
/*
* NetBios Datagram Handler (IP/UDP)
*/
#define DGM_DIRECT_UNIQ 0x10
#define DGM_DIRECT_GROUP 0x11
#define DGM_BROADCAST 0x12
#define DGM_ERROR 0x13
#define DGM_QUERY 0x14
#define DGM_POSITIVE_RES 0x15
#define DGM_NEGATIVE_RES 0x16
int
AliasHandleUdpNbt(
struct libalias *la,
struct ip *pip, /* IP packet to examine/patch */
struct alias_link *lnk,
struct in_addr *alias_address,
u_short alias_port
)
{
struct udphdr *uh;
NbtDataHeader *ndh;
u_char *p = NULL;
char *pmax;
(void)la;
(void)lnk;
/* Calculate data length of UDP packet */
uh = (struct udphdr *)ip_next(pip);
pmax = (char *)uh + ntohs(uh->uh_ulen);
ndh = (NbtDataHeader *)udp_next(uh);
if ((char *)(ndh + 1) > pmax)
return (-1);
#ifdef DEBUG
printf("\nType=%02x,", ndh->type);
#endif
switch (ndh->type) {
case DGM_DIRECT_UNIQ:
case DGM_DIRECT_GROUP:
case DGM_BROADCAST:
p = (u_char *) ndh + 14;
p = AliasHandleName(p, pmax); /* Source Name */
p = AliasHandleName(p, pmax); /* Destination Name */
break;
case DGM_ERROR:
p = (u_char *) ndh + 11;
break;
case DGM_QUERY:
case DGM_POSITIVE_RES:
case DGM_NEGATIVE_RES:
p = (u_char *) ndh + 10;
p = AliasHandleName(p, pmax); /* Destination Name */
break;
}
if (p == NULL || (char *)p > pmax)
p = NULL;
#ifdef DEBUG
printf("%s:%d-->", inet_ntoa(ndh->source_ip), ntohs(ndh->source_port));
#endif
/* Doing an IP address and Port number Translation */
if (uh->uh_sum != 0) {
int acc;
u_short *sptr;
acc = ndh->source_port;
acc -= alias_port;
sptr = (u_short *) & (ndh->source_ip);
acc += *sptr++;
acc += *sptr;
sptr = (u_short *) alias_address;
acc -= *sptr++;
acc -= *sptr;
ADJUST_CHECKSUM(acc, uh->uh_sum);
}
ndh->source_ip = *alias_address;
ndh->source_port = alias_port;
#ifdef DEBUG
printf("%s:%d\n", inet_ntoa(ndh->source_ip), ntohs(ndh->source_port));
fflush(stdout);
#endif
return ((p == NULL) ? -1 : 0);
}
/* Question Section */
#define QS_TYPE_NB 0x0020
#define QS_TYPE_NBSTAT 0x0021
#define QS_CLAS_IN 0x0001
typedef struct {
u_short type; /* The type of Request */
u_short class; /* The class of Request */
} NBTNsQuestion;
static u_char *
AliasHandleQuestion(
u_short count,
NBTNsQuestion * q,
char *pmax,
NBTArguments * nbtarg)
{
(void)nbtarg;
while (count != 0) {
/* Name Filed */
q = (NBTNsQuestion *) AliasHandleName((u_char *) q, pmax);
if (q == NULL || (char *)(q + 1) > pmax) {
q = NULL;
break;
}
/* Type and Class filed */
switch (ntohs(q->type)) {
case QS_TYPE_NB:
case QS_TYPE_NBSTAT:
q = q + 1;
break;
default:
#ifdef DEBUG
printf("\nUnknown Type on Question %0x\n", ntohs(q->type));
#endif
break;
}
count--;
}
/* Set up to out of Question Section */
return ((u_char *) q);
}
/* Resource Record */
#define RR_TYPE_A 0x0001
#define RR_TYPE_NS 0x0002
#define RR_TYPE_NULL 0x000a
#define RR_TYPE_NB 0x0020
#define RR_TYPE_NBSTAT 0x0021
#define RR_CLAS_IN 0x0001
#define SizeOfNsResource 8
typedef struct {
u_short type;
u_short class;
unsigned int ttl;
u_short rdlen;
} NBTNsResource;
#define SizeOfNsRNB 6
typedef struct {
u_short g: 1 , ont:2, resv:13;
struct in_addr addr;
} NBTNsRNB;
static u_char *
AliasHandleResourceNB(
NBTNsResource * q,
char *pmax,
NBTArguments * nbtarg)
{
NBTNsRNB *nb;
u_short bcount;
if (q == NULL || (char *)(q + 1) > pmax)
return (NULL);
/* Check out a length */
bcount = ntohs(q->rdlen);
/* Forward to Resource NB position */
nb = (NBTNsRNB *) ((u_char *) q + SizeOfNsResource);
/* Processing all in_addr array */
#ifdef DEBUG
printf("NB rec[%s", inet_ntoa(nbtarg->oldaddr));
printf("->%s, %dbytes] ", inet_ntoa(nbtarg->newaddr), bcount);
#endif
while (nb != NULL && bcount != 0) {
if ((char *)(nb + 1) > pmax) {
nb = NULL;
break;
}
#ifdef DEBUG
printf("<%s>", inet_ntoa(nb->addr));
#endif
if (!bcmp(&nbtarg->oldaddr, &nb->addr, sizeof(struct in_addr))) {
if (*nbtarg->uh_sum != 0) {
int acc;
u_short *sptr;
sptr = (u_short *) & (nb->addr);
acc = *sptr++;
acc += *sptr;
sptr = (u_short *) & (nbtarg->newaddr);
acc -= *sptr++;
acc -= *sptr;
ADJUST_CHECKSUM(acc, *nbtarg->uh_sum);
}
nb->addr = nbtarg->newaddr;
#ifdef DEBUG
printf("O");
#endif
}
#ifdef DEBUG
else {
printf(".");
}
#endif
nb = (NBTNsRNB *) ((u_char *) nb + SizeOfNsRNB);
bcount -= SizeOfNsRNB;
}
if (nb == NULL || (char *)(nb + 1) > pmax) {
nb = NULL;
}
return ((u_char *) nb);
}
#define SizeOfResourceA 6
typedef struct {
struct in_addr addr;
} NBTNsResourceA;
static u_char *
AliasHandleResourceA(
NBTNsResource * q,
char *pmax,
NBTArguments * nbtarg)
{
NBTNsResourceA *a;
u_short bcount;
if (q == NULL || (char *)(q + 1) > pmax)
return (NULL);
/* Forward to Resource A position */
a = (NBTNsResourceA *) ((u_char *) q + sizeof(NBTNsResource));
/* Check out of length */
bcount = ntohs(q->rdlen);
/* Processing all in_addr array */
#ifdef DEBUG
printf("Arec [%s", inet_ntoa(nbtarg->oldaddr));
printf("->%s]", inet_ntoa(nbtarg->newaddr));
#endif
while (bcount != 0) {
if (a == NULL || (char *)(a + 1) > pmax)
return (NULL);
#ifdef DEBUG
printf("..%s", inet_ntoa(a->addr));
#endif
if (!bcmp(&nbtarg->oldaddr, &a->addr, sizeof(struct in_addr))) {
if (*nbtarg->uh_sum != 0) {
int acc;
u_short *sptr;
sptr = (u_short *) & (a->addr); /* Old */
acc = *sptr++;
acc += *sptr;
sptr = (u_short *) & nbtarg->newaddr; /* New */
acc -= *sptr++;
acc -= *sptr;
ADJUST_CHECKSUM(acc, *nbtarg->uh_sum);
}
a->addr = nbtarg->newaddr;
}
a++; /* XXXX */
bcount -= SizeOfResourceA;
}
if (a == NULL || (char *)(a + 1) > pmax)
a = NULL;
return ((u_char *) a);
}
typedef struct {
u_short opcode:4, flags:8, resv:4;
} NBTNsResourceNULL;
static u_char *
AliasHandleResourceNULL(
NBTNsResource * q,
char *pmax,
NBTArguments * nbtarg)
{
NBTNsResourceNULL *n;
u_short bcount;
(void)nbtarg;
if (q == NULL || (char *)(q + 1) > pmax)
return (NULL);
/* Forward to Resource NULL position */
n = (NBTNsResourceNULL *) ((u_char *) q + sizeof(NBTNsResource));
/* Check out of length */
bcount = ntohs(q->rdlen);
/* Processing all in_addr array */
while (bcount != 0) {
if ((char *)(n + 1) > pmax) {
n = NULL;
break;
}
n++;
bcount -= sizeof(NBTNsResourceNULL);
}
if ((char *)(n + 1) > pmax)
n = NULL;
return ((u_char *) n);
}
static u_char *
AliasHandleResourceNS(
NBTNsResource * q,
char *pmax,
NBTArguments * nbtarg)
{
NBTNsResourceNULL *n;
u_short bcount;
(void)nbtarg;
if (q == NULL || (char *)(q + 1) > pmax)
return (NULL);
/* Forward to Resource NULL position */
n = (NBTNsResourceNULL *) ((u_char *) q + sizeof(NBTNsResource));
/* Check out of length */
bcount = ntohs(q->rdlen);
/* Resource Record Name Filed */
q = (NBTNsResource *) AliasHandleName((u_char *) n, pmax); /* XXX */
if (q == NULL || (char *)((u_char *) n + bcount) > pmax)
return (NULL);
else
return ((u_char *) n + bcount);
}
typedef struct {
u_short numnames;
} NBTNsResourceNBSTAT;
static u_char *
AliasHandleResourceNBSTAT(
NBTNsResource * q,
char *pmax,
NBTArguments * nbtarg)
{
NBTNsResourceNBSTAT *n;
u_short bcount;
(void)nbtarg;
if (q == NULL || (char *)(q + 1) > pmax)
return (NULL);
/* Forward to Resource NBSTAT position */
n = (NBTNsResourceNBSTAT *) ((u_char *) q + sizeof(NBTNsResource));
/* Check out of length */
bcount = ntohs(q->rdlen);
if (q == NULL || (char *)((u_char *) n + bcount) > pmax)
return (NULL);
else
return ((u_char *) n + bcount);
}
static u_char *
AliasHandleResource(
u_short count,
NBTNsResource * q,
char *pmax,
NBTArguments
* nbtarg)
{
while (count != 0) {
/* Resource Record Name Filed */
q = (NBTNsResource *) AliasHandleName((u_char *) q, pmax);
if (q == NULL || (char *)(q + 1) > pmax)
break;
#ifdef DEBUG
printf("type=%02x, count=%d\n", ntohs(q->type), count);
#endif
/* Type and Class filed */
switch (ntohs(q->type)) {
case RR_TYPE_NB:
q = (NBTNsResource *) AliasHandleResourceNB(
q,
pmax,
nbtarg
);
break;
case RR_TYPE_A:
q = (NBTNsResource *) AliasHandleResourceA(
q,
pmax,
nbtarg
);
break;
case RR_TYPE_NS:
q = (NBTNsResource *) AliasHandleResourceNS(
q,
pmax,
nbtarg
);
break;
case RR_TYPE_NULL:
q = (NBTNsResource *) AliasHandleResourceNULL(
q,
pmax,
nbtarg
);
break;
case RR_TYPE_NBSTAT:
q = (NBTNsResource *) AliasHandleResourceNBSTAT(
q,
pmax,
nbtarg
);
break;
default:
#ifdef DEBUG
printf(
"\nUnknown Type of Resource %0x\n",
ntohs(q->type)
);
fflush(stdout);
#endif
break;
}
count--;
}
return ((u_char *) q);
}
int
AliasHandleUdpNbtNS(
struct libalias *la,
struct ip *pip, /* IP packet to examine/patch */
struct alias_link *lnk,
struct in_addr *alias_address,
u_short * alias_port,
struct in_addr *original_address,
u_short * original_port)
{
struct udphdr *uh;
NbtNSHeader *nsh;
u_char *p;
char *pmax;
NBTArguments nbtarg;
(void)la;
(void)lnk;
/* Set up Common Parameter */
nbtarg.oldaddr = *alias_address;
nbtarg.oldport = *alias_port;
nbtarg.newaddr = *original_address;
nbtarg.newport = *original_port;
/* Calculate data length of UDP packet */
uh = (struct udphdr *)ip_next(pip);
nbtarg.uh_sum = &(uh->uh_sum);
nsh = (NbtNSHeader *)udp_next(uh);
p = (u_char *) (nsh + 1);
pmax = (char *)uh + ntohs(uh->uh_ulen);
if ((char *)(nsh + 1) > pmax)
return (-1);
#ifdef DEBUG
printf(" [%s] ID=%02x, op=%01x, flag=%02x, rcode=%01x, qd=%04x"
", an=%04x, ns=%04x, ar=%04x, [%d]-->",
nsh->dir ? "Response" : "Request",
nsh->nametrid,
nsh->opcode,
nsh->nmflags,
nsh->rcode,
ntohs(nsh->qdcount),
ntohs(nsh->ancount),
ntohs(nsh->nscount),
ntohs(nsh->arcount),
(u_char *) p - (u_char *) nsh
);
#endif
/* Question Entries */
if (ntohs(nsh->qdcount) != 0) {
p = AliasHandleQuestion(
ntohs(nsh->qdcount),
(NBTNsQuestion *) p,
pmax,
&nbtarg
);
}
/* Answer Resource Records */
if (ntohs(nsh->ancount) != 0) {
p = AliasHandleResource(
ntohs(nsh->ancount),
(NBTNsResource *) p,
pmax,
&nbtarg
);
}
/* Authority Resource Recodrs */
if (ntohs(nsh->nscount) != 0) {
p = AliasHandleResource(
ntohs(nsh->nscount),
(NBTNsResource *) p,
pmax,
&nbtarg
);
}
/* Additional Resource Recodrs */
if (ntohs(nsh->arcount) != 0) {
p = AliasHandleResource(
ntohs(nsh->arcount),
(NBTNsResource *) p,
pmax,
&nbtarg
);
}
#ifdef DEBUG
PrintRcode(nsh->rcode);
#endif
return ((p == NULL) ? -1 : 0);
}
|