/*- * Written by Atsushi Murai * 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. * * $OpenBSD: alias_nbt.c,v 1.9 2004/05/31 02:21:17 brad 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 ) See HISTORY file for record of revisions. */ /* Includes */ #include #include #include #include #include #include #include #include #include #include #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 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); }