[apple/network_cmds.git] / alias / alias_nbt.c

/*
 * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*-
 * 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.
 *
 * Based upon:
 * $FreeBSD: src/lib/libalias/alias_nbt.c,v 1.4.2.3 2001/08/01 09:52:26 obrien Exp $
 *
 *  TODO:
 *       oClean up. 
 *       oConsidering for word alignment for other platform.
 */
/*
    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???=%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 ip 		  	*pip,	 /* IP packet to examine/patch */
	struct alias_link 	*link,
	struct in_addr		*alias_address,
    u_short 		alias_port
) {
    struct udphdr *	uh;
    NbtDataHeader 	*ndh;
    u_char		*p = NULL;
    char		*pmax;
        
    /* Calculate data length of UDP packet */
    uh =  (struct udphdr *) ((char *) pip + (pip->ip_hl << 2));
    pmax = (char *)uh + ntohs( uh->uh_ulen );

	ndh = (NbtDataHeader *)((char *)uh + (sizeof (struct udphdr)));
    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 a 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)
{

	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;

	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;

	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;

	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 ip 		  	*pip,	 /* IP packet to examine/patch */
	struct alias_link 	*link,
	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;

	/* 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 *) ((char *) pip + (pip->ip_hl << 2));
	nbtarg.uh_sum	=	&(uh->uh_sum);
	nsh = (NbtNSHeader *)((char *)uh + (sizeof(struct udphdr)));
	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);
}
Commit	Line	Data
b7080c8e	1	/*
7ba0088d A	2	* Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
a2c93a76 A	6	* The contents of this file constitute Original Code as defined in and
	7	* are subject to the Apple Public Source License Version 1.1 (the
	8	* "License"). You may not use this file except in compliance with the
	9	* License. Please obtain a copy of the License at
	10	* http://www.apple.com/publicsource and read it before using this file.
7ba0088d	11	*
a2c93a76 A	12	* This Original Code and all software distributed under the License are
a2c93a76 A	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
7ba0088d A	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
7ba0088d A	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
a2c93a76 A	16	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	17	* License for the specific language governing rights and limitations
	18	* under the License.
7ba0088d A	19	*
	20	* @APPLE_LICENSE_HEADER_END@
	21	*/
	22	/*-
b7080c8e	23	* Written by Atsushi Murai <amurai@spec.co.jp>
7ba0088d A	24	* Copyright (c) 1998, System Planning and Engineering Co.
7ba0088d A	25	* All rights reserved.
b7080c8e	26	*
7ba0088d A	27	* Redistribution and use in source and binary forms, with or without
	28	* modification, are permitted provided that the following conditions
	29	* are met:
	30	* 1. Redistributions of source code must retain the above copyright
	31	* notice, this list of conditions and the following disclaimer.
	32	* 2. Redistributions in binary form must reproduce the above copyright
	33	* notice, this list of conditions and the following disclaimer in the
	34	* documentation and/or other materials provided with the distribution.
b7080c8e	35	*
7ba0088d A	36	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	37	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	38	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	39	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	40	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	41	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	42	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	43	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	44	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	45	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	46	* SUCH DAMAGE.
b7080c8e	47	*
7ba0088d A	48	* Based upon:
7ba0088d A	49	* $FreeBSD: src/lib/libalias/alias_nbt.c,v 1.4.2.3 2001/08/01 09:52:26 obrien Exp $
b7080c8e A	50	*
	51	* TODO:
	52	* oClean up.
	53	* oConsidering for word alignment for other platform.
	54	*/
	55	/*
	56	alias_nbt.c performs special processing for NetBios over TCP/IP
	57	sessions by UDP.
	58
	59	Initial version: May, 1998 (Atsushi Murai <amurai@spec.co.jp>)
	60
	61	See HISTORY file for record of revisions.
	62	*/
	63
	64	/* Includes */
	65	#include <ctype.h>
	66	#include <stdio.h>
	67	#include <string.h>
	68	#include <sys/types.h>
	69	#include <netinet/in_systm.h>
	70	#include <netinet/in.h>
	71	#include <arpa/inet.h>
	72	#include <netinet/ip.h>
	73	#include <netinet/udp.h>
	74	#include <netinet/tcp.h>
	75
	76	#include "alias_local.h"
	77
b7080c8e A	78	typedef struct {
	79	struct in_addr oldaddr;
	80	u_short oldport;
	81	struct in_addr newaddr;
	82	u_short newport;
	83	u_short *uh_sum;
	84	} NBTArguments;
	85
	86	typedef struct {
	87	unsigned char type;
	88	unsigned char flags;
	89	u_short id;
	90	struct in_addr source_ip;
	91	u_short source_port;
	92	u_short len;
	93	u_short offset;
	94	} NbtDataHeader;
	95
	96	#define OpQuery 0
	97	#define OpUnknown 4
	98	#define OpRegist 5
	99	#define OpRelease 6
	100	#define OpWACK 7
	101	#define OpRefresh 8
	102	typedef struct {
	103	u_short nametrid;
	104	u_short dir:1, opcode:4, nmflags:7, rcode:4;
	105	u_short qdcount;
	106	u_short ancount;
	107	u_short nscount;
	108	u_short arcount;
	109	} NbtNSHeader;
	110
	111	#define FMT_ERR 0x1
	112	#define SRV_ERR 0x2
	113	#define IMP_ERR 0x4
	114	#define RFS_ERR 0x5
	115	#define ACT_ERR 0x6
	116	#define CFT_ERR 0x7
	117
	118
	119	#ifdef DEBUG
	120	static void PrintRcode( u_char rcode ) {
	121
	122	switch (rcode) {
	123	case FMT_ERR:
	124	printf("\nFormat Error.");
	125	case SRV_ERR:
	126	printf("\nSever failure.");
	127	case IMP_ERR:
	128	printf("\nUnsupported request error.\n");
	129	case RFS_ERR:
	130	printf("\nRefused error.\n");
	131	case ACT_ERR:
	132	printf("\nActive error.\n");
	133	case CFT_ERR:
	134	printf("\nName in conflict error.\n");
	135	default:
	136	printf("\n???=%0x\n", rcode );
	137
	138	}
	139	}
	140	#endif
	141
142
143	/* Handling Name field */
144	static u_char AliasHandleName ( u_char p, char *pmax ) {
145
146	u_char *s;
147	u_char c;
148	int compress;
149
150	/* Following length field */
151
152	if (p == NULL \|\| (char *)p >= pmax)
153	return(NULL);
154
155	if (*p & 0xc0 ) {
156	p = p + 2;
157	if ((char *)p > pmax)
158	return(NULL);
159	return ((u_char *)p);
160	}
161	while ( ( *p & 0x3f) != 0x00 ) {
162	s = p + 1;
163	if ( *p == 0x20 )
164	compress = 1;
165	else
166	compress = 0;
167
168	/* Get next length field */
169	p = (u_char )(p + (p & 0x3f) + 1);
170	if ((char *)p > pmax) {
171	p = NULL;
172	break;
173	}
174	#ifdef DEBUG
175	printf(":");
176	#endif
177	while (s < p) {
178	if ( compress == 1 ) {
179	c = (u_char )(((((s & 0x0f) << 4) \| ((s+1) & 0x0f)) - 0x11));
180	#ifdef DEBUG
181	if (isprint( c ) )
182	printf("%c", c );
183	else
184	printf("<0x%02x>", c );
185	#endif
186	s +=2;
187	} else {
188	#ifdef DEBUG
189	printf("%c", *s);
190	#endif
191	s++;
192	}
193	}
194	#ifdef DEBUG
195	printf(":");
196	#endif
197	fflush(stdout);
198	}
199
200	/* Set up to out of Name field */
201	if (p == NULL \|\| (char *)p >= pmax)
202	p = NULL;
203	else
204	p++;
205	return ((u_char *)p);
206	}
207
208	/*
209	* NetBios Datagram Handler (IP/UDP)
210	*/
211	#define DGM_DIRECT_UNIQ 0x10
212	#define DGM_DIRECT_GROUP 0x11
213	#define DGM_BROADCAST 0x12
214	#define DGM_ERROR 0x13
215	#define DGM_QUERY 0x14
216	#define DGM_POSITIVE_RES 0x15
217	#define DGM_NEGATIVE_RES 0x16
218
219	int AliasHandleUdpNbt(
220	struct ip pip, / IP packet to examine/patch */
221	struct alias_link *link,
222	struct in_addr *alias_address,
223	u_short alias_port
224	) {
225	struct udphdr * uh;
226	NbtDataHeader *ndh;
227	u_char *p = NULL;
228	char *pmax;
229
230	/* Calculate data length of UDP packet */
231	uh = (struct udphdr ) ((char ) pip + (pip->ip_hl << 2));
232	pmax = (char *)uh + ntohs( uh->uh_ulen );
233
234	ndh = (NbtDataHeader )((char )uh + (sizeof (struct udphdr)));
235	if ((char *)(ndh + 1) > pmax)
236	return(-1);
237	#ifdef DEBUG
238	printf("\nType=%02x,", ndh->type );
239	#endif
240	switch ( ndh->type ) {
241	case DGM_DIRECT_UNIQ:
242	case DGM_DIRECT_GROUP:
243	case DGM_BROADCAST:
244	p = (u_char *)ndh + 14;
245	p = AliasHandleName ( p, pmax ); /* Source Name */
246	p = AliasHandleName ( p, pmax ); /* Destination Name */
247	break;
248	case DGM_ERROR:
249	p = (u_char *)ndh + 11;
250	break;
251	case DGM_QUERY:
252	case DGM_POSITIVE_RES:
253	case DGM_NEGATIVE_RES:
254	p = (u_char *)ndh + 10;
255	p = AliasHandleName ( p, pmax ); /* Destination Name */
256	break;
257	}
258	if (p == NULL \|\| (char *)p > pmax)
259	p = NULL;
260	#ifdef DEBUG
261	printf("%s:%d-->", inet_ntoa(ndh->source_ip), ntohs(ndh->source_port) );
262	#endif
263	/* Doing a IP address and Port number Translation */
264	if ( uh->uh_sum != 0 ) {
265	int acc;
266	u_short *sptr;
267	acc = ndh->source_port;
268	acc -= alias_port;
269	sptr = (u_short *) &(ndh->source_ip);
270	acc += *sptr++;
271	acc += *sptr;
272	sptr = (u_short *) alias_address;
273	acc -= *sptr++;
274	acc -= *sptr;
7ba0088d	275	ADJUST_CHECKSUM(acc, uh->uh_sum);
b7080c8e A	276	}
	277	ndh->source_ip = *alias_address;
	278	ndh->source_port = alias_port;
	279	#ifdef DEBUG
	280	printf("%s:%d\n", inet_ntoa(ndh->source_ip), ntohs(ndh->source_port) );
	281	fflush(stdout);
	282	#endif
	283	return((p == NULL) ? -1 : 0);
	284	}
	285	/* Question Section */
	286	#define QS_TYPE_NB 0x0020
	287	#define QS_TYPE_NBSTAT 0x0021
	288	#define QS_CLAS_IN 0x0001
	289	typedef struct {
	290	u_short type; /* The type of Request */
	291	u_short class; /* The class of Request */
	292	} NBTNsQuestion;
	293
	294	static u_char *
	295	AliasHandleQuestion(
	296	u_short count,
	297	NBTNsQuestion *q,
	298	char *pmax,
	299	NBTArguments *nbtarg)
	300	{
	301
	302	while ( count != 0 ) {
	303	/* Name Filed */
	304	q = (NBTNsQuestion )AliasHandleName((u_char )q, pmax);
	305
	306	if (q == NULL \|\| (char *)(q + 1) > pmax) {
	307	q = NULL;
	308	break;
	309	}
	310
	311	/* Type and Class filed */
	312	switch ( ntohs(q->type) ) {
	313	case QS_TYPE_NB:
	314	case QS_TYPE_NBSTAT:
	315	q= q+1;
	316	break;
	317	default:
	318	#ifdef DEBUG
	319	printf("\nUnknown Type on Question %0x\n", ntohs(q->type) );
	320	#endif
	321	break;
	322	}
	323	count--;
	324	}
	325
	326	/* Set up to out of Question Section */
	327	return ((u_char *)q);
	328	}
	329
	330	/* Resource Record */
	331	#define RR_TYPE_A 0x0001
	332	#define RR_TYPE_NS 0x0002
	333	#define RR_TYPE_NULL 0x000a
	334	#define RR_TYPE_NB 0x0020
	335	#define RR_TYPE_NBSTAT 0x0021
	336	#define RR_CLAS_IN 0x0001
	337	#define SizeOfNsResource 8
	338	typedef struct {
	339	u_short type;
340	u_short class;
341	unsigned int ttl;
342	u_short rdlen;
343	} NBTNsResource;
344
345	#define SizeOfNsRNB 6
346	typedef struct {
347	u_short g:1, ont:2, resv:13;
348	struct in_addr addr;
349	} NBTNsRNB;
350
351	static u_char *
352	AliasHandleResourceNB(
353	NBTNsResource *q,
354	char *pmax,
355	NBTArguments *nbtarg)
356	{
357	NBTNsRNB *nb;
358	u_short bcount;
359
360	if (q == NULL \|\| (char *)(q + 1) > pmax)
361	return(NULL);
362	/* Check out a length */
363	bcount = ntohs(q->rdlen);
364
365	/* Forward to Resource NB position */
366	nb = (NBTNsRNB )((u_char )q + SizeOfNsResource);
367
368	/* Processing all in_addr array */
369	#ifdef DEBUG
370	printf("NB rec[%s", inet_ntoa(nbtarg->oldaddr));
371	printf("->%s, %dbytes] ",inet_ntoa(nbtarg->newaddr ), bcount);
372	#endif
373	while ( nb != NULL && bcount != 0 ) {
374	if ((char *)(nb + 1) > pmax) {
375	nb = NULL;
376	break;
377	}
378	#ifdef DEBUG
379	printf("<%s>", inet_ntoa(nb->addr) );
380	#endif
381	if (!bcmp(&nbtarg->oldaddr,&nb->addr, sizeof(struct in_addr) ) ) {
382	if ( *nbtarg->uh_sum != 0 ) {
383	int acc;
384	u_short *sptr;
385
386	sptr = (u_short *) &(nb->addr);
387	acc = *sptr++;
388	acc += *sptr;
389	sptr = (u_short *) &(nbtarg->newaddr);
390	acc -= *sptr++;
391	acc -= *sptr;
7ba0088d	392	ADJUST_CHECKSUM(acc, *nbtarg->uh_sum);
b7080c8e A	393	}
	394
	395	nb->addr = nbtarg->newaddr;
	396	#ifdef DEBUG
	397	printf("O");
	398	#endif
	399	}
	400	#ifdef DEBUG
	401	else {
	402	printf(".");
	403	}
	404	#endif
	405	nb=(NBTNsRNB )((u_char )nb + SizeOfNsRNB);
	406	bcount -= SizeOfNsRNB;
	407	}
	408	if (nb == NULL \|\| (char *)(nb + 1) > pmax) {
	409	nb = NULL;
	410	}
	411
	412	return ((u_char *)nb);
	413	}
	414
	415	#define SizeOfResourceA 6
	416	typedef struct {
	417	struct in_addr addr;
	418	} NBTNsResourceA;
	419
	420	static u_char *
	421	AliasHandleResourceA(
	422	NBTNsResource *q,
	423	char *pmax,
	424	NBTArguments *nbtarg)
	425	{
	426	NBTNsResourceA *a;
	427	u_short bcount;
	428
	429	if (q == NULL \|\| (char *)(q + 1) > pmax)
	430	return(NULL);
	431
	432	/* Forward to Resource A position */
	433	a = (NBTNsResourceA )( (u_char )q + sizeof(NBTNsResource) );
	434
	435	/* Check out of length */
	436	bcount = ntohs(q->rdlen);
	437
	438	/* Processing all in_addr array */
	439	#ifdef DEBUG
	440	printf("Arec [%s", inet_ntoa(nbtarg->oldaddr));
	441	printf("->%s]",inet_ntoa(nbtarg->newaddr ));
	442	#endif
	443	while ( bcount != 0 ) {
	444	if (a == NULL \|\| (char *)(a + 1) > pmax)
	445	return(NULL);
	446	#ifdef DEBUG
	447	printf("..%s", inet_ntoa(a->addr) );
	448	#endif
	449	if ( !bcmp(&nbtarg->oldaddr, &a->addr, sizeof(struct in_addr) ) ) {
	450	if ( *nbtarg->uh_sum != 0 ) {
	451	int acc;
	452	u_short *sptr;
	453
	454	sptr = (u_short ) &(a->addr); / Old */
	455	acc = *sptr++;
	456	acc += *sptr;
457	sptr = (u_short ) &nbtarg->newaddr; / New */
458	acc -= *sptr++;
459	acc -= *sptr;
7ba0088d	460	ADJUST_CHECKSUM(acc, *nbtarg->uh_sum);
b7080c8e A	461	}
	462
	463	a->addr = nbtarg->newaddr;
	464	}
	465	a++; /XXXX/
	466	bcount -= SizeOfResourceA;
	467	}
	468	if (a == NULL \|\| (char *)(a + 1) > pmax)
	469	a = NULL;
	470	return ((u_char *)a);
	471	}
	472
	473	typedef struct {
	474	u_short opcode:4, flags:8, resv:4;
	475	} NBTNsResourceNULL;
	476
	477	static u_char *
	478	AliasHandleResourceNULL(
	479	NBTNsResource *q,
	480	char *pmax,
	481	NBTArguments *nbtarg)
	482	{
	483	NBTNsResourceNULL *n;
	484	u_short bcount;
	485
	486	if (q == NULL \|\| (char *)(q + 1) > pmax)
	487	return(NULL);
	488
	489	/* Forward to Resource NULL position */
	490	n = (NBTNsResourceNULL )( (u_char )q + sizeof(NBTNsResource) );
	491
	492	/* Check out of length */
	493	bcount = ntohs(q->rdlen);
	494
	495	/* Processing all in_addr array */
	496	while ( bcount != 0 ) {
	497	if ((char *)(n + 1) > pmax) {
	498	n = NULL;
	499	break;
	500	}
	501	n++;
	502	bcount -= sizeof(NBTNsResourceNULL);
	503	}
	504	if ((char *)(n + 1) > pmax)
	505	n = NULL;
	506
	507	return ((u_char *)n);
	508	}
	509
	510	static u_char *
	511	AliasHandleResourceNS(
	512	NBTNsResource *q,
	513	char *pmax,
	514	NBTArguments *nbtarg)
	515	{
	516	NBTNsResourceNULL *n;
	517	u_short bcount;
	518
	519	if (q == NULL \|\| (char *)(q + 1) > pmax)
	520	return(NULL);
	521
	522	/* Forward to Resource NULL position */
	523	n = (NBTNsResourceNULL )( (u_char )q + sizeof(NBTNsResource) );
	524
525	/* Check out of length */
526	bcount = ntohs(q->rdlen);
527
528	/* Resource Record Name Filed */
529	q = (NBTNsResource )AliasHandleName( (u_char )n, pmax ); /* XXX */
530
531	if (q == NULL \|\| (char )((u_char )n + bcount) > pmax)
532	return(NULL);
533	else
534	return ((u_char *)n + bcount);
535	}
536
537	typedef struct {
538	u_short numnames;
539	} NBTNsResourceNBSTAT;
540
541	static u_char *
542	AliasHandleResourceNBSTAT(
543	NBTNsResource *q,
544	char *pmax,
545	NBTArguments *nbtarg)
546	{
547	NBTNsResourceNBSTAT *n;
548	u_short bcount;
549
550	if (q == NULL \|\| (char *)(q + 1) > pmax)
551	return(NULL);
552
553	/* Forward to Resource NBSTAT position */
554	n = (NBTNsResourceNBSTAT )( (u_char )q + sizeof(NBTNsResource) );
555
556	/* Check out of length */
557	bcount = ntohs(q->rdlen);
558
559	if (q == NULL \|\| (char )((u_char )n + bcount) > pmax)
560	return(NULL);
561	else
562	return ((u_char *)n + bcount);
563	}
564
565	static u_char *
566	AliasHandleResource(
567	u_short count,
568	NBTNsResource *q,
569	char *pmax,
570	NBTArguments
571	*nbtarg)
572	{
573	while ( count != 0 ) {
574	/* Resource Record Name Filed */
575	q = (NBTNsResource )AliasHandleName( (u_char )q, pmax );
576
577	if (q == NULL \|\| (char *)(q + 1) > pmax)
578	break;
579	#ifdef DEBUG
580	printf("type=%02x, count=%d\n", ntohs(q->type), count );
581	#endif
582
583	/* Type and Class filed */
584	switch ( ntohs(q->type) ) {
585	case RR_TYPE_NB:
586	q = (NBTNsResource *)AliasHandleResourceNB(
587	q,
588	pmax,
589	nbtarg
590	);
591	break;
592	case RR_TYPE_A:
593	q = (NBTNsResource *)AliasHandleResourceA(
594	q,
595	pmax,
596	nbtarg
597	);
598	break;
599	case RR_TYPE_NS:
600	q = (NBTNsResource *)AliasHandleResourceNS(
601	q,
602	pmax,
603	nbtarg
604	);
605	break;
606	case RR_TYPE_NULL:
607	q = (NBTNsResource *)AliasHandleResourceNULL(
608	q,
609	pmax,
610	nbtarg
611	);
612	break;
613	case RR_TYPE_NBSTAT:
614	q = (NBTNsResource *)AliasHandleResourceNBSTAT(
615	q,
616	pmax,
617	nbtarg
618	);
619	break;
620	default:
621	#ifdef DEBUG
622	printf(
623	"\nUnknown Type of Resource %0x\n",
624	ntohs(q->type)
625	);
626	#endif
627	break;
628	}
629	count--;
630	}
631	fflush(stdout);
632	return ((u_char *)q);
633	}
634
635	int AliasHandleUdpNbtNS(
636	struct ip pip, / IP packet to examine/patch */
637	struct alias_link *link,
638	struct in_addr *alias_address,
639	u_short *alias_port,
640	struct in_addr *original_address,
641	u_short *original_port )
642	{
643	struct udphdr * uh;
644	NbtNSHeader * nsh;
645	u_char * p;
646	char *pmax;
647	NBTArguments nbtarg;
648
649	/* Set up Common Parameter */
650	nbtarg.oldaddr = *alias_address;
651	nbtarg.oldport = *alias_port;
652	nbtarg.newaddr = *original_address;
653	nbtarg.newport = *original_port;
654
655	/* Calculate data length of UDP packet */
656	uh = (struct udphdr ) ((char ) pip + (pip->ip_hl << 2));
657	nbtarg.uh_sum = &(uh->uh_sum);
658	nsh = (NbtNSHeader )((char )uh + (sizeof(struct udphdr)));
659	p = (u_char *)(nsh + 1);
660	pmax = (char *)uh + ntohs( uh->uh_ulen );
661
662	if ((char *)(nsh + 1) > pmax)
663	return(-1);
664
665	#ifdef DEBUG
666	printf(" [%s] ID=%02x, op=%01x, flag=%02x, rcode=%01x, qd=%04x"
667	", an=%04x, ns=%04x, ar=%04x, [%d]-->",
668	nsh->dir ? "Response": "Request",
669	nsh->nametrid,
670	nsh->opcode,
671	nsh->nmflags,
672	nsh->rcode,
673	ntohs(nsh->qdcount),
674	ntohs(nsh->ancount),
675	ntohs(nsh->nscount),
676	ntohs(nsh->arcount),
677	(u_char )p -(u_char )nsh
678	);
679	#endif
680
681	/* Question Entries */
682	if (ntohs(nsh->qdcount) !=0 ) {
683	p = AliasHandleQuestion(
684	ntohs(nsh->qdcount),
685	(NBTNsQuestion *)p,
686	pmax,
687	&nbtarg
688	);
689	}
690
691	/* Answer Resource Records */
692	if (ntohs(nsh->ancount) !=0 ) {
693	p = AliasHandleResource(
694	ntohs(nsh->ancount),
695	(NBTNsResource *)p,
696	pmax,
697	&nbtarg
698	);
699	}
700
701	/* Authority Resource Recodrs */
702	if (ntohs(nsh->nscount) !=0 ) {
703	p = AliasHandleResource(
704	ntohs(nsh->nscount),
705	(NBTNsResource *)p,
706	pmax,
707	&nbtarg
708	);
709	}
710
711	/* Additional Resource Recodrs */
712	if (ntohs(nsh->arcount) !=0 ) {
713	p = AliasHandleResource(
714	ntohs(nsh->arcount),
715	(NBTNsResource *)p,
716	pmax,
717	&nbtarg
718	);
719	}
720
721	#ifdef DEBUG
722	PrintRcode(nsh->rcode);
723	#endif
724	return ((p == NULL) ? -1 : 0);
725	}