alias_nbt.c@ 91623

Last change on this file since 91623 was 83597, checked in by vboxsync, 5 years ago
NAT: bugref:9694 - libalias NBT - IP header is verified, but UDP header is not, so cross check UDP length against IP header.
Property svn:eol-style set to `native` Property svn:keywords set to `Author Date Id Revision`
File size: 22.8 KB

Line
1	/*-
2	* Written by Atsushi Murai <amurai@spec.co.jp>
3	* Copyright (c) 1998, System Planning and Engineering Co.
4	* All rights reserved.
5	*
6	* Redistribution and use in source and binary forms, with or without
7	* modification, are permitted provided that the following conditions
8	* are met:
9	* 1. Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.
11	* 2. Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.
14	*
15	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25	* SUCH DAMAGE.
26	* TODO:
27	* oClean up.
28	* oConsidering for word alignment for other platform.
29	*/
30
31	#ifndef VBOX
32	#include <sys/cdefs.h>
33	__FBSDID("$FreeBSD: src/sys/netinet/libalias/alias_nbt.c,v 1.20.8.1 2009/04/15 03:14:26 kensmith Exp $");
34
35	/*
36	alias_nbt.c performs special processing for NetBios over TCP/IP
37	sessions by UDP.
38
39	Initial version: May, 1998 (Atsushi Murai <amurai@spec.co.jp>)
40
41	See HISTORY file for record of revisions.
42	*/
43
44	/* Includes */
45	#ifdef _KERNEL
46	#include <sys/param.h>
47	#include <sys/systm.h>
48	#include <sys/kernel.h>
49	#include <sys/module.h>
50	#else
51	#include <errno.h>
52	#include <sys/types.h>
53	#include <stdio.h>
54	#endif
55
56	#include <netinet/in_systm.h>
57	#include <netinet/in.h>
58	#include <netinet/ip.h>
59	#include <netinet/udp.h>
60
61	#ifdef _KERNEL
62	#include <netinet/libalias/alias_local.h>
63	#include <netinet/libalias/alias_mod.h>
64	#else
65	#include "alias_local.h"
66	#include "alias_mod.h"
67	#endif
68	#else /* VBOX */
69	# include <iprt/ctype.h>
70	# include <slirp.h>
71	# include "alias_local.h"
72	# include "alias_mod.h"
73	# define isprint RT_C_IS_PRINT
74	#endif /* VBOX */
75
76	#define NETBIOS_NS_PORT_NUMBER 137
77	#define NETBIOS_DGM_PORT_NUMBER 138
78
79	static int
80	AliasHandleUdpNbt(struct libalias , struct ip , struct alias_link *,
81	struct in_addr *, u_short);
82
83	static int
84	AliasHandleUdpNbtNS(struct libalias , struct ip , struct alias_link *,
85	struct in_addr , u_short , struct in_addr , u_short );
86	static int
87	fingerprint1(struct libalias la, struct ip pip, struct alias_data *ah)
88	{
89
90	#ifdef VBOX
91	NOREF(la);
92	NOREF(pip);
93	#endif
94	if (ah->dport == NULL \|\| ah->sport == NULL \|\| ah->lnk == NULL \|\|
95	ah->aaddr == NULL \|\| ah->aport == NULL)
96	return (-1);
97	if (ntohs(*ah->dport) == NETBIOS_DGM_PORT_NUMBER
98	\|\| ntohs(*ah->sport) == NETBIOS_DGM_PORT_NUMBER)
99	return (0);
100	return (-1);
101	}
102
103	static int
104	protohandler1(struct libalias la, struct ip pip, struct alias_data *ah)
105	{
106
107	AliasHandleUdpNbt(la, pip, ah->lnk, ah->aaddr, *ah->aport);
108	return (0);
109	}
110
111	static int
112	fingerprint2(struct libalias la, struct ip pip, struct alias_data *ah)
113	{
114
115	#ifdef VBOX
116	NOREF(la);
117	NOREF(pip);
118	#endif
119	if (ah->dport == NULL \|\| ah->sport == NULL \|\| ah->lnk == NULL \|\|
120	ah->aaddr == NULL \|\| ah->aport == NULL)
121	return (-1);
122	if (ntohs(*ah->dport) == NETBIOS_NS_PORT_NUMBER
123	\|\| ntohs(*ah->sport) == NETBIOS_NS_PORT_NUMBER)
124	return (0);
125	return (-1);
126	}
127
128	static int
129	protohandler2in(struct libalias la, struct ip pip, struct alias_data *ah)
130	{
131
132	AliasHandleUdpNbtNS(la, pip, ah->lnk, ah->aaddr, ah->aport,
133	ah->oaddr, ah->dport);
134	return (0);
135	}
136
137	static int
138	protohandler2out(struct libalias la, struct ip pip, struct alias_data *ah)
139	{
140
141	AliasHandleUdpNbtNS(la, pip, ah->lnk, &pip->ip_src, ah->sport,
142	ah->aaddr, ah->aport);
143	return (0);
144	}
145
146	/* Kernel module definition. */
147	#ifndef VBOX
148	struct proto_handler handlers[] = {
149	{
150	.pri = 130,
151	.dir = IN\|OUT,
152	.proto = UDP,
153	.fingerprint = &fingerprint1,
154	.protohandler = &protohandler1
155	},
156	{
157	.pri = 140,
158	.dir = IN,
159	.proto = UDP,
160	.fingerprint = &fingerprint2,
161	.protohandler = &protohandler2in
162	},
163	{
164	.pri = 140,
165	.dir = OUT,
166	.proto = UDP,
167	.fingerprint = &fingerprint2,
168	.protohandler = &protohandler2out
169	},
170	{ EOH }
171	};
172	#else /* VBOX */
173	#define handlers pData->nbt_module
174	#endif /* VBOX */
175
176	#ifndef VBOX
177	static int
178	mod_handler(module_t mod, int type, void *data)
179	#else /* VBOX */
180	static int nbt_alias_handler(PNATState pData, int type);
181
182	int
183	nbt_alias_load(PNATState pData)
184	{
185	return nbt_alias_handler(pData, MOD_LOAD);
186	}
187
188	int
189	nbt_alias_unload(PNATState pData)
190	{
191	return nbt_alias_handler(pData, MOD_UNLOAD);
192	}
193	static int
194	nbt_alias_handler(PNATState pData, int type)
195	#endif /* VBOX */
196	{
197	int error;
198	#ifdef VBOX
199	if (handlers == NULL)
200	handlers = RTMemAllocZ(4 * sizeof(struct proto_handler));
201	handlers[0].pri = 130;
202	handlers[0].dir = IN\|OUT;
203	handlers[0].proto = UDP;
204	handlers[0].fingerprint = &fingerprint1;
205	handlers[0].protohandler = &protohandler1;
206
207
208	handlers[1].pri = 140;
209	handlers[1].dir = IN;
210	handlers[1].proto = UDP;
211	handlers[1].fingerprint = &fingerprint2;
212	handlers[1].protohandler = &protohandler2in;
213
214
215	handlers[2].pri = 140;
216	handlers[2].dir = OUT;
217	handlers[2].proto = UDP;
218	handlers[2].fingerprint = &fingerprint2;
219	handlers[2].protohandler = &protohandler2out;
220
221	handlers[3].pri = (u_int)EOH;
222	#endif /* VBOX */
223
224	switch (type) {
225	case MOD_LOAD:
226	error = 0;
227	#ifdef VBOX
228	LibAliasAttachHandlers(pData, handlers);
229	#else
230	LibAliasAttachHandlers(handlers);
231	#endif
232	break;
233	case MOD_UNLOAD:
234	error = 0;
235	#ifdef VBOX
236	LibAliasDetachHandlers(pData, handlers);
237	RTMemFree(handlers);
238	handlers = NULL;
239	#else
240	LibAliasDetachHandlers(handlers);
241	#endif
242	break;
243	default:
244	error = EINVAL;
245	}
246	return (error);
247	}
248
249	#ifndef VBOX
250	#ifdef _KERNEL
251	static
252	#endif
253	moduledata_t alias_mod = {
254	"alias_nbt", mod_handler, NULL
255	};
256	#endif /* !VBOX */
257
258	#ifdef _KERNEL
259	DECLARE_MODULE(alias_nbt, alias_mod, SI_SUB_DRIVERS, SI_ORDER_SECOND);
260	MODULE_VERSION(alias_nbt, 1);
261	MODULE_DEPEND(alias_nbt, libalias, 1, 1, 1);
262	#endif
263
264	typedef struct {
265	struct in_addr oldaddr;
266	u_short oldport;
267	struct in_addr newaddr;
268	u_short newport;
269	u_short *uh_sum;
270	} NBTArguments;
271
272	typedef struct {
273	unsigned char type;
274	unsigned char flags;
275	u_short id;
276	struct in_addr source_ip;
277	u_short source_port;
278	u_short len;
279	u_short offset;
280	} NbtDataHeader;
281
282	#define OpQuery 0
283	#define OpUnknown 4
284	#define OpRegist 5
285	#define OpRelease 6
286	#define OpWACK 7
287	#define OpRefresh 8
288	typedef struct {
289	#ifndef VBOX
290	u_short nametrid;
291	u_short dir: 1, opcode:4, nmflags:7, rcode:4;
292	#else
293	unsigned nametrid:16;
294	unsigned dir: 1, opcode:4, nmflags:7, rcode:4;
295	#endif
296	u_short qdcount;
297	u_short ancount;
298	u_short nscount;
299	u_short arcount;
300	} NbtNSHeader;
301	AssertCompileSize(NbtNSHeader, 12);
302
303	#define FMT_ERR 0x1
304	#define SRV_ERR 0x2
305	#define IMP_ERR 0x4
306	#define RFS_ERR 0x5
307	#define ACT_ERR 0x6
308	#define CFT_ERR 0x7
309
310
311	#ifdef LIBALIAS_DEBUG
312	static void
313	PrintRcode(u_char rcode)
314	{
315
316	switch (rcode) {
317	case FMT_ERR:
318	printf("\nFormat Error.");
319	case SRV_ERR:
320	printf("\nSever failure.");
321	case IMP_ERR:
322	printf("\nUnsupported request error.\n");
323	case RFS_ERR:
324	printf("\nRefused error.\n");
325	case ACT_ERR:
326	printf("\nActive error.\n");
327	case CFT_ERR:
328	printf("\nName in conflict error.\n");
329	default:
330	printf("\n?%c?=%0x\n", '?', rcode);
331
332	}
333	}
334
335	#endif
336
337
338	/* Handling Name field */
339	static u_char *
340	AliasHandleName(u_char * p, char *pmax)
341	{
342
343	u_char *s;
344	#ifdef LIBALIAS_DEBUG
345	u_char c;
346	#endif
347	int compress;
348
349	/* Following length field */
350
351	if (p == NULL \|\| (char *)p >= pmax)
352	return (NULL);
353
354	if (*p & 0xc0) {
355	p = p + 2;
356	if ((char *)p > pmax)
357	return (NULL);
358	return ((u_char *) p);
359	}
360	while ((*p & 0x3f) != 0x00) {
361	s = p + 1;
362	if (*p == 0x20)
363	compress = 1;
364	else
365	compress = 0;
366
367	/* Get next length field */
368	p = (u_char ) (p + (p & 0x3f) + 1);
369	if ((char *)p > pmax) {
370	p = NULL;
371	break;
372	}
373	#ifdef LIBALIAS_DEBUG
374	printf(":");
375	#endif
376	while (s < p) {
377	if (compress == 1) {
378	#ifdef LIBALIAS_DEBUG
379	c = (u_char) (((((s & 0x0f) << 4) \| ((s + 1) & 0x0f)) - 0x11));
380	if (isprint(c))
381	printf("%c", c);
382	else
383	printf("<0x%02x>", c);
384	#endif
385	s += 2;
386	} else {
387	#ifdef LIBALIAS_DEBUG
388	printf("%c", *s);
389	#endif
390	s++;
391	}
392	}
393	#ifdef LIBALIAS_DEBUG
394	printf(":");
395	fflush(stdout);
396	#endif
397	}
398
399	/* Set up to out of Name field */
400	if (p == NULL \|\| (char *)p >= pmax)
401	p = NULL;
402	else
403	p++;
404	return ((u_char *) p);
405	}
406
407	/*
408	* NetBios Datagram Handler (IP/UDP)
409	*/
410	#define DGM_DIRECT_UNIQ 0x10
411	#define DGM_DIRECT_GROUP 0x11
412	#define DGM_BROADCAST 0x12
413	#define DGM_ERROR 0x13
414	#define DGM_QUERY 0x14
415	#define DGM_POSITIVE_RES 0x15
416	#define DGM_NEGATIVE_RES 0x16
417
418	static int
419	AliasHandleUdpNbt(
420	struct libalias *la,
421	struct ip pip, / IP packet to examine/patch */
422	struct alias_link *lnk,
423	struct in_addr *alias_address,
424	u_short alias_port
425	)
426	{
427	struct udphdr *uh;
428	NbtDataHeader *ndh;
429	u_char *p = NULL;
430	char *pmax;
431
432	(void)la;
433	(void)lnk;
434
435	/* Calculate data length of UDP packet */
436	uh = (struct udphdr *)ip_next(pip);
437	pmax = (char *)uh + ntohs(uh->uh_ulen);
438
439	/* IP header has been verified, cross-check uh_ulen */
440	if (RT_UNLIKELY(pmax != (char *)pip + ntohs(pip->ip_len)))
441	return (-1);
442
443	ndh = (NbtDataHeader *)udp_next(uh);
444	if ((char *)(ndh + 1) > pmax)
445	return (-1);
446	#ifdef LIBALIAS_DEBUG
447	printf("\nType=%02x,", ndh->type);
448	#endif
449	switch (ndh->type) {
450	case DGM_DIRECT_UNIQ:
451	case DGM_DIRECT_GROUP:
452	case DGM_BROADCAST:
453	p = (u_char *) ndh + 14;
454	p = AliasHandleName(p, pmax); /* Source Name */
455	p = AliasHandleName(p, pmax); /* Destination Name */
456	break;
457	case DGM_ERROR:
458	p = (u_char *) ndh + 11;
459	break;
460	case DGM_QUERY:
461	case DGM_POSITIVE_RES:
462	case DGM_NEGATIVE_RES:
463	p = (u_char *) ndh + 10;
464	p = AliasHandleName(p, pmax); /* Destination Name */
465	break;
466	}
467	if (p == NULL \|\| (char *)p > pmax)
468	p = NULL;
469	#ifdef LIBALIAS_DEBUG
470	printf("%s:%d-->", inet_ntoa(ndh->source_ip), ntohs(ndh->source_port));
471	#endif
472	/* Doing an IP address and Port number Translation */
473	if (uh->uh_sum != 0) {
474	int acc;
475	u_short *sptr;
476
477	acc = ndh->source_port;
478	acc -= alias_port;
479	sptr = (u_short *) & (ndh->source_ip);
480	acc += *sptr++;
481	acc += *sptr;
482	sptr = (u_short *) alias_address;
483	acc -= *sptr++;
484	acc -= *sptr;
485	ADJUST_CHECKSUM(acc, uh->uh_sum);
486	}
487	ndh->source_ip = *alias_address;
488	ndh->source_port = alias_port;
489	#ifdef LIBALIAS_DEBUG
490	printf("%s:%d\n", inet_ntoa(ndh->source_ip), ntohs(ndh->source_port));
491	fflush(stdout);
492	#endif
493	return ((p == NULL) ? -1 : 0);
494	}
495
496	/* Question Section */
497	#define QS_TYPE_NB 0x0020
498	#define QS_TYPE_NBSTAT 0x0021
499	#define QS_CLAS_IN 0x0001
500	typedef struct {
501	u_short type; /* The type of Request */
502	u_short class; /* The class of Request */
503	} NBTNsQuestion;
504
505	static u_char *
506	AliasHandleQuestion(
507	u_short count,
508	NBTNsQuestion * q,
509	char *pmax,
510	NBTArguments * nbtarg)
511	{
512
513	(void)nbtarg;
514
515	while (count != 0) {
516	/* Name Filed */
517	q = (NBTNsQuestion ) AliasHandleName((u_char ) q, pmax);
518
519	if (q == NULL \|\| (char *)(q + 1) > pmax) {
520	q = NULL;
521	break;
522	}
523	/* Type and Class filed */
524	switch (ntohs(q->type)) {
525	case QS_TYPE_NB:
526	case QS_TYPE_NBSTAT:
527	q = q + 1;
528	break;
529	default:
530	#ifdef LIBALIAS_DEBUG
531	printf("\nUnknown Type on Question %0x\n", ntohs(q->type));
532	#endif
533	break;
534	}
535	count--;
536	}
537
538	/* Set up to out of Question Section */
539	return ((u_char *) q);
540	}
541
542	/* Resource Record */
543	#define RR_TYPE_A 0x0001
544	#define RR_TYPE_NS 0x0002
545	#define RR_TYPE_NULL 0x000a
546	#define RR_TYPE_NB 0x0020
547	#define RR_TYPE_NBSTAT 0x0021
548	#define RR_CLAS_IN 0x0001
549	#define SizeOfNsResource 8
550	typedef struct {
551	u_short type;
552	u_short class;
553	unsigned int ttl;
554	u_short rdlen;
555	} NBTNsResource;
556
557	#define SizeOfNsRNB 6
558	typedef struct {
559	#ifndef VBOX
560	u_short g: 1 , ont:2, resv:13;
561	#else
562	unsigned g: 1 , ont:2, resv:13;
563	#endif
564	struct in_addr addr;
565	} NBTNsRNB;
566	AssertCompileSize(NBTNsRNB, 8);
567
568	static u_char *
569	AliasHandleResourceNB(
570	NBTNsResource * q,
571	char *pmax,
572	NBTArguments * nbtarg)
573	{
574	NBTNsRNB *nb;
575	u_short bcount;
576
577	if (q == NULL \|\| (char *)(q + 1) > pmax)
578	return (NULL);
579	/* Check out a length */
580	bcount = ntohs(q->rdlen);
581
582	/* Forward to Resource NB position */
583	nb = (NBTNsRNB ) ((u_char ) q + SizeOfNsResource);
584
585	/* Processing all in_addr array */
586	#ifdef LIBALIAS_DEBUG
587	printf("NB rec[%s", inet_ntoa(nbtarg->oldaddr));
588	printf("->%s, %dbytes] ", inet_ntoa(nbtarg->newaddr), bcount);
589	#endif
590	while (nb != NULL && bcount != 0) {
591	if ((char *)(nb + 1) > pmax) {
592	nb = NULL;
593	break;
594	}
595	#ifdef LIBALIAS_DEBUG
596	printf("<%s>", inet_ntoa(nb->addr));
597	#endif
598	if (!bcmp(&nbtarg->oldaddr, &nb->addr, sizeof(struct in_addr))) {
599	if (*nbtarg->uh_sum != 0) {
600	int acc;
601	u_short *sptr;
602
603	sptr = (u_short *) & (nb->addr);
604	acc = *sptr++;
605	acc += *sptr;
606	sptr = (u_short *) & (nbtarg->newaddr);
607	acc -= *sptr++;
608	acc -= *sptr;
609	ADJUST_CHECKSUM(acc, *nbtarg->uh_sum);
610	}
611	nb->addr = nbtarg->newaddr;
612	#ifdef LIBALIAS_DEBUG
613	printf("O");
614	#endif
615	}
616	#ifdef LIBALIAS_DEBUG
617	else {
618	printf(".");
619	}
620	#endif
621	nb = (NBTNsRNB ) ((u_char ) nb + SizeOfNsRNB);
622	bcount -= SizeOfNsRNB;
623	}
624	if (nb == NULL \|\| (char *)(nb + 1) > pmax) {
625	nb = NULL;
626	}
627	return ((u_char *) nb);
628	}
629
630	#define SizeOfResourceA 6
631	typedef struct {
632	struct in_addr addr;
633	} NBTNsResourceA;
634
635	static u_char *
636	AliasHandleResourceA(
637	NBTNsResource * q,
638	char *pmax,
639	NBTArguments * nbtarg)
640	{
641	NBTNsResourceA *a;
642	u_short bcount;
643
644	if (q == NULL \|\| (char *)(q + 1) > pmax)
645	return (NULL);
646
647	/* Forward to Resource A position */
648	a = (NBTNsResourceA ) ((u_char ) q + sizeof(NBTNsResource));
649
650	/* Check out of length */
651	bcount = ntohs(q->rdlen);
652
653	/* Processing all in_addr array */
654	#ifdef LIBALIAS_DEBUG
655	printf("Arec [%s", inet_ntoa(nbtarg->oldaddr));
656	printf("->%s]", inet_ntoa(nbtarg->newaddr));
657	#endif
658	while (bcount != 0) {
659	if (a == NULL \|\| (char *)(a + 1) > pmax)
660	return (NULL);
661	#ifdef LIBALIAS_DEBUG
662	printf("..%s", inet_ntoa(a->addr));
663	#endif
664	if (!bcmp(&nbtarg->oldaddr, &a->addr, sizeof(struct in_addr))) {
665	if (*nbtarg->uh_sum != 0) {
666	int acc;
667	u_short *sptr;
668
669	sptr = (u_short ) & (a->addr); / Old */
670	acc = *sptr++;
671	acc += *sptr;
672	sptr = (u_short ) & nbtarg->newaddr; / New */
673	acc -= *sptr++;
674	acc -= *sptr;
675	ADJUST_CHECKSUM(acc, *nbtarg->uh_sum);
676	}
677	a->addr = nbtarg->newaddr;
678	}
679	a++; /* XXXX */
680	bcount -= SizeOfResourceA;
681	}
682	if (a == NULL \|\| (char *)(a + 1) > pmax)
683	a = NULL;
684	return ((u_char *) a);
685	}
686
687	typedef struct {
688	#ifndef VBOX
689	u_short opcode:4, flags:8, resv:4;
690	#else
691	u_short hidden; /* obviously not needed */
692	#endif
693	} NBTNsResourceNULL;
694	AssertCompileSize(NBTNsResourceNULL, 2);
695
696	static u_char *
697	AliasHandleResourceNULL(
698	NBTNsResource * q,
699	char *pmax,
700	NBTArguments * nbtarg)
701	{
702	NBTNsResourceNULL *n;
703	u_short bcount;
704
705	(void)nbtarg;
706
707	if (q == NULL \|\| (char *)(q + 1) > pmax)
708	return (NULL);
709
710	/* Forward to Resource NULL position */
711	n = (NBTNsResourceNULL ) ((u_char ) q + sizeof(NBTNsResource));
712
713	/* Check out of length */
714	bcount = ntohs(q->rdlen);
715
716	/* Processing all in_addr array */
717	while (bcount != 0) {
718	if ((char *)(n + 1) > pmax) {
719	n = NULL;
720	break;
721	}
722	n++;
723	bcount -= sizeof(NBTNsResourceNULL);
724	}
725	if ((char *)(n + 1) > pmax)
726	n = NULL;
727
728	return ((u_char *) n);
729	}
730
731	static u_char *
732	AliasHandleResourceNS(
733	NBTNsResource * q,
734	char *pmax,
735	NBTArguments * nbtarg)
736	{
737	NBTNsResourceNULL *n;
738	u_short bcount;
739
740	(void)nbtarg;
741
742	if (q == NULL \|\| (char *)(q + 1) > pmax)
743	return (NULL);
744
745	/* Forward to Resource NULL position */
746	n = (NBTNsResourceNULL ) ((u_char ) q + sizeof(NBTNsResource));
747
748	/* Check out of length */
749	bcount = ntohs(q->rdlen);
750
751	/* Resource Record Name Filed */
752	q = (NBTNsResource ) AliasHandleName((u_char ) n, pmax); /* XXX */
753
754	if (q == NULL \|\| (char )((u_char ) n + bcount) > pmax)
755	return (NULL);
756	else
757	return ((u_char *) n + bcount);
758	}
759
760	typedef struct {
761	u_short numnames;
762	} NBTNsResourceNBSTAT;
763
764	static u_char *
765	AliasHandleResourceNBSTAT(
766	NBTNsResource * q,
767	char *pmax,
768	NBTArguments * nbtarg)
769	{
770	NBTNsResourceNBSTAT *n;
771	u_short bcount;
772
773	(void)nbtarg;
774
775	if (q == NULL \|\| (char *)(q + 1) > pmax)
776	return (NULL);
777
778	/* Forward to Resource NBSTAT position */
779	n = (NBTNsResourceNBSTAT ) ((u_char ) q + sizeof(NBTNsResource));
780
781	/* Check out of length */
782	bcount = ntohs(q->rdlen);
783
784	if ((char )((u_char ) n + bcount) > pmax)
785	return (NULL);
786	else
787	return ((u_char *) n + bcount);
788	}
789
790	static u_char *
791	AliasHandleResource(
792	u_short count,
793	NBTNsResource * q,
794	char *pmax,
795	NBTArguments
796	* nbtarg)
797	{
798	while (count != 0) {
799	/* Resource Record Name Filed */
800	q = (NBTNsResource ) AliasHandleName((u_char ) q, pmax);
801
802	if (q == NULL \|\| (char *)(q + 1) > pmax)
803	break;
804	#ifdef LIBALIAS_DEBUG
805	printf("type=%02x, count=%d\n", ntohs(q->type), count);
806	#endif
807
808	/* Type and Class filed */
809	switch (ntohs(q->type)) {
810	case RR_TYPE_NB:
811	q = (NBTNsResource *) AliasHandleResourceNB(
812	q,
813	pmax,
814	nbtarg
815	);
816	break;
817	case RR_TYPE_A:
818	q = (NBTNsResource *) AliasHandleResourceA(
819	q,
820	pmax,
821	nbtarg
822	);
823	break;
824	case RR_TYPE_NS:
825	q = (NBTNsResource *) AliasHandleResourceNS(
826	q,
827	pmax,
828	nbtarg
829	);
830	break;
831	case RR_TYPE_NULL:
832	q = (NBTNsResource *) AliasHandleResourceNULL(
833	q,
834	pmax,
835	nbtarg
836	);
837	break;
838	case RR_TYPE_NBSTAT:
839	q = (NBTNsResource *) AliasHandleResourceNBSTAT(
840	q,
841	pmax,
842	nbtarg
843	);
844	break;
845	default:
846	#ifdef LIBALIAS_DEBUG
847	printf(
848	"\nUnknown Type of Resource %0x\n",
849	ntohs(q->type)
850	);
851	fflush(stdout);
852	#endif
853	break;
854	}
855	count--;
856	}
857	return ((u_char *) q);
858	}
859
860	static int
861	AliasHandleUdpNbtNS(
862	struct libalias *la,
863	struct ip pip, / IP packet to examine/patch */
864	struct alias_link *lnk,
865	struct in_addr *alias_address,
866	u_short * alias_port,
867	struct in_addr *original_address,
868	u_short * original_port)
869	{
870	struct udphdr *uh;
871	NbtNSHeader *nsh;
872	u_char *p;
873	char *pmax;
874	NBTArguments nbtarg;
875
876	(void)la;
877	(void)lnk;
878
879	/* Set up Common Parameter */
880	nbtarg.oldaddr = *alias_address;
881	nbtarg.oldport = *alias_port;
882	nbtarg.newaddr = *original_address;
883	nbtarg.newport = *original_port;
884
885	/* Calculate data length of UDP packet */
886	uh = (struct udphdr *)ip_next(pip);
887	nbtarg.uh_sum = &(uh->uh_sum);
888	nsh = (NbtNSHeader *)udp_next(uh);
889	p = (u_char *) (nsh + 1);
890	pmax = (char *)uh + ntohs(uh->uh_ulen);
891
892	/* IP header has been verified, cross-check uh_ulen */
893	if (RT_UNLIKELY(pmax != (char *)pip + ntohs(pip->ip_len)))
894	return (-1);
895
896	if ((char *)(nsh + 1) > pmax)
897	return (-1);
898
899	#ifdef LIBALIAS_DEBUG
900	printf(" [%s] ID=%02x, op=%01x, flag=%02x, rcode=%01x, qd=%04x"
901	", an=%04x, ns=%04x, ar=%04x, [%d]-->",
902	nsh->dir ? "Response" : "Request",
903	nsh->nametrid,
904	nsh->opcode,
905	nsh->nmflags,
906	nsh->rcode,
907	ntohs(nsh->qdcount),
908	ntohs(nsh->ancount),
909	ntohs(nsh->nscount),
910	ntohs(nsh->arcount),
911	(u_char ) p - (u_char ) nsh
912	);
913	#endif
914
915	/* Question Entries */
916	if (ntohs(nsh->qdcount) != 0) {
917	p = AliasHandleQuestion(
918	ntohs(nsh->qdcount),
919	(NBTNsQuestion *) p,
920	pmax,
921	&nbtarg
922	);
923	}
924	/* Answer Resource Records */
925	if (ntohs(nsh->ancount) != 0) {
926	p = AliasHandleResource(
927	ntohs(nsh->ancount),
928	(NBTNsResource *) p,
929	pmax,
930	&nbtarg
931	);
932	}
933	/* Authority Resource Recodrs */
934	if (ntohs(nsh->nscount) != 0) {
935	p = AliasHandleResource(
936	ntohs(nsh->nscount),
937	(NBTNsResource *) p,
938	pmax,
939	&nbtarg
940	);
941	}
942	/* Additional Resource Recodrs */
943	if (ntohs(nsh->arcount) != 0) {
944	p = AliasHandleResource(
945	ntohs(nsh->arcount),
946	(NBTNsResource *) p,
947	pmax,
948	&nbtarg
949	);
950	}
951	#ifdef LIBALIAS_DEBUG
952	PrintRcode(nsh->rcode);
953	#endif
954	return ((p == NULL) ? -1 : 0);
955	}

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source: vbox/trunk/src/VBox/Devices/Network/slirp/libalias/alias_nbt.c@ 91623

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