FreeBSD-5.3/lib/libalias/alias_nbt.c
/*-
* 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: src/lib/libalias/alias_nbt.c,v 1.15 2004/07/06 12:13:28 des Exp $");
/*
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 */
#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netinet/ip.h>
#include <netinet/udp.h>
#include <netinet/tcp.h>
#include "alias_local.h"
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(":");
#endif
fflush(stdout);
}
/* 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)
);
#endif
break;
}
count--;
}
fflush(stdout);
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);
}