lib/libalias/alias_nbt.c

   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  *
  27  * $FreeBSD: src/lib/libalias/alias_nbt.c,v 1.4.2.3 2001/08/01 09:52:26 obrien Exp $
  28  * $DragonFly: src/lib/libalias/alias_nbt.c,v 1.4 2006/03/18 19:43:18 swildner Exp $
  29  *
  30  *  TODO:
  31  *       oClean up.
  32  *       oConsidering for word alignment for other platform.
  33  */
  34 /*
  35     alias_nbt.c performs special processing for NetBios over TCP/IP
  36     sessions by UDP.
  37
  38     Initial version:  May, 1998  (Atsushi Murai <amurai@spec.co.jp>)
  39
  40     See HISTORY file for record of revisions.
  41 */
  42
  43 /* Includes */
  44 #include <sys/param.h>
  45 #include <ctype.h>
  46 #include <stdio.h>
  47 #include <string.h>
  48 #include <netinet/in_systm.h>
  49 #include <netinet/in.h>
  50 #include <arpa/inet.h>
  51 #include <netinet/ip.h>
  52 #include <netinet/udp.h>
  53 #include <netinet/tcp.h>
  54
  55 #include "alias_local.h"
  56
  57 typedef struct {
  58         struct in_addr          oldaddr;
  59         u_short                         oldport;
  60         struct in_addr          newaddr;
  61         u_short                         newport;
  62         u_short                         *uh_sum;
  63 } NBTArguments;
  64
  65 typedef struct {
  66         unsigned char   type;
  67         unsigned char   flags;
  68         u_short                 id;
  69         struct in_addr  source_ip;
  70         u_short                 source_port;
  71         u_short                 len;
  72         u_short                 offset;
  73 } NbtDataHeader;
  74
  75 #define OpQuery         0
  76 #define OpUnknown       4
  77 #define OpRegist        5
  78 #define OpRelease       6
  79 #define OpWACK          7
  80 #define OpRefresh       8
  81 typedef struct {
  82         u_short                 nametrid;
  83         u_short                 dir:1, opcode:4, nmflags:7, rcode:4;
  84         u_short                 qdcount;
  85         u_short                 ancount;
  86         u_short                 nscount;
  87         u_short                 arcount;
  88 } NbtNSHeader;
  89
  90 #define FMT_ERR         0x1
  91 #define SRV_ERR         0x2
  92 #define IMP_ERR         0x4
  93 #define RFS_ERR         0x5
  94 #define ACT_ERR         0x6
  95 #define CFT_ERR         0x7
  96
  97
  98 #ifdef DEBUG
  99 static void PrintRcode( u_char rcode )  {
 100
 101         switch (rcode) {
 102                 case FMT_ERR:
 103                         printf("\nFormat Error.");
 104                 case SRV_ERR:
 105                         printf("\nSever failure.");
 106                 case IMP_ERR:
 107                         printf("\nUnsupported request error.\n");
 108                 case RFS_ERR:
 109                         printf("\nRefused error.\n");
 110                 case ACT_ERR:
 111                         printf("\nActive error.\n");
 112                 case CFT_ERR:
 113                         printf("\nName in conflict error.\n");
 114                 default:
 115                         printf("\n??\?=%0x\n", rcode );
 116
 117         }
 118 }
 119 #endif
 120
 121
 122 /* Handling Name field */
 123 static u_char *AliasHandleName ( u_char *p, char *pmax ) {
 124
 125         u_char *s;
 126 #ifdef DEBUG
 127         u_char c;
 128 #endif
 129         int             compress;
 130
 131         /* Following length field */
 132
 133         if (p == NULL || (char *)p >= pmax)
 134                 return(NULL);
 135
 136         if (*p & 0xc0 ) {
 137                 p = p + 2;
 138                 if ((char *)p > pmax)
 139                         return(NULL);
 140                 return ((u_char *)p);
 141         }
 142         while ( ( *p & 0x3f) != 0x00 ) {
 143                 s = p + 1;
 144                 if ( *p == 0x20 )
 145                         compress = 1;
 146                 else
 147                         compress = 0;
 148
 149                 /* Get next length field */
 150                 p = (u_char *)(p + (*p & 0x3f) + 1);
 151                 if ((char *)p > pmax) {
 152                         p = NULL;
 153                         break;
 154                 }
 155 #ifdef DEBUG
 156                 printf(":");
 157 #endif
 158                 while (s < p) {
 159                         if ( compress == 1 ) {
 160 #ifdef DEBUG
 161                                 c = (u_char )(((((*s & 0x0f) << 4) | (*(s+1) & 0x0f)) - 0x11));
 162                                 if (isprint( c ) )
 163                                         printf("%c", c );
 164                                 else
 165                                         printf("<0x%02x>", c );
 166 #endif
 167                                 s +=2;
 168                         } else {
 169 #ifdef DEBUG
 170                                 printf("%c", *s);
 171 #endif
 172                                 s++;
 173                         }
 174                 }
 175 #ifdef DEBUG
 176                 printf(":");
 177 #endif
 178                 fflush(stdout);
 179     }
 180
 181         /* Set up to out of Name field */
 182         if (p == NULL || (char *)p >= pmax)
 183             p = NULL;
 184         else
 185             p++;
 186         return ((u_char *)p);
 187 }
 188
 189 /*
 190  * NetBios Datagram Handler (IP/UDP)
 191  */
 192 #define DGM_DIRECT_UNIQ         0x10
 193 #define DGM_DIRECT_GROUP        0x11
 194 #define DGM_BROADCAST           0x12
 195 #define DGM_ERROR                       0x13
 196 #define DGM_QUERY                       0x14
 197 #define DGM_POSITIVE_RES        0x15
 198 #define DGM_NEGATIVE_RES        0x16
 199
 200 int AliasHandleUdpNbt(
 201         struct ip                       *pip,    /* IP packet to examine/patch */
 202         struct alias_link       *link,
 203         struct in_addr          *alias_address,
 204     u_short             alias_port
 205 ) {
 206     struct udphdr *     uh;
 207     NbtDataHeader       *ndh;
 208     u_char              *p = NULL;
 209     char                *pmax;
 210
 211     /* Calculate data length of UDP packet */
 212     uh =  (struct udphdr *) ((char *) pip + (pip->ip_hl << 2));
 213     pmax = (char *)uh + ntohs( uh->uh_ulen );
 214
 215         ndh = (NbtDataHeader *)((char *)uh + (sizeof (struct udphdr)));
 216     if ((char *)(ndh + 1) > pmax)
 217             return(-1);
 218 #ifdef DEBUG
 219         printf("\nType=%02x,", ndh->type );
 220 #endif
 221         switch ( ndh->type ) {
 222                 case DGM_DIRECT_UNIQ:
 223                 case DGM_DIRECT_GROUP:
 224                 case DGM_BROADCAST:
 225                         p = (u_char *)ndh + 14;
 226                     p = AliasHandleName ( p, pmax ); /* Source Name */
 227                     p = AliasHandleName ( p, pmax ); /* Destination Name */
 228                         break;
 229                 case DGM_ERROR:
 230                         p = (u_char *)ndh + 11;
 231                         break;
 232                 case DGM_QUERY:
 233                 case DGM_POSITIVE_RES:
 234                 case DGM_NEGATIVE_RES:
 235                         p = (u_char *)ndh + 10;
 236                     p = AliasHandleName ( p, pmax ); /* Destination Name */
 237                         break;
 238         }
 239     if (p == NULL || (char *)p > pmax)
 240             p = NULL;
 241 #ifdef DEBUG
 242         printf("%s:%d-->", inet_ntoa(ndh->source_ip), ntohs(ndh->source_port) );
 243 #endif
 244         /* Doing a IP address and Port number Translation */
 245         if ( uh->uh_sum != 0 ) {
 246                 int                             acc;
 247                 u_short                 *sptr;
 248                 acc  = ndh->source_port;
 249                 acc -= alias_port;
 250                 sptr = (u_short *) &(ndh->source_ip);
 251                 acc += *sptr++;
 252                 acc += *sptr;
 253                 sptr = (u_short *) alias_address;
 254                 acc -= *sptr++;
 255                 acc -= *sptr;
 256                 ADJUST_CHECKSUM(acc, uh->uh_sum);
 257         }
 258     ndh->source_ip = *alias_address;
 259     ndh->source_port = alias_port;
 260 #ifdef DEBUG
 261         printf("%s:%d\n", inet_ntoa(ndh->source_ip), ntohs(ndh->source_port) );
 262         fflush(stdout);
 263 #endif
 264     return((p == NULL) ? -1 : 0);
 265 }
 266 /* Question Section */
 267 #define QS_TYPE_NB              0x0020
 268 #define QS_TYPE_NBSTAT  0x0021
 269 #define QS_CLAS_IN              0x0001
 270 typedef struct {
 271         u_short type;   /* The type of Request */
 272         u_short class;  /* The class of Request */
 273 } NBTNsQuestion;
 274
 275 static u_char *
 276 AliasHandleQuestion(
 277     u_short count,
 278                                                         NBTNsQuestion *q,
 279     char *pmax,
 280                                                         NBTArguments  *nbtarg)
 281 {
 282
 283         while ( count != 0 ) {
 284                 /* Name Filed */
 285                 q = (NBTNsQuestion *)AliasHandleName((u_char *)q, pmax);
 286
 287                 if (q == NULL || (char *)(q + 1) > pmax) {
 288                         q = NULL;
 289                         break;
 290                 }
 291
 292                 /* Type and Class filed */
 293                 switch ( ntohs(q->type) ) {
 294                         case QS_TYPE_NB:
 295                         case QS_TYPE_NBSTAT:
 296                                 q= q+1;
 297                         break;
 298                         default:
 299 #ifdef DEBUG
 300                                 printf("\nUnknown Type on Question %0x\n", ntohs(q->type) );
 301 #endif
 302                         break;
 303                 }
 304                 count--;
 305         }
 306
 307         /* Set up to out of Question Section */
 308         return ((u_char *)q);
 309 }
 310
 311 /* Resource Record */
 312 #define RR_TYPE_A               0x0001
 313 #define RR_TYPE_NS              0x0002
 314 #define RR_TYPE_NULL    0x000a
 315 #define RR_TYPE_NB              0x0020
 316 #define RR_TYPE_NBSTAT  0x0021
 317 #define RR_CLAS_IN              0x0001
 318 #define SizeOfNsResource        8
 319 typedef struct {
 320         u_short type;
 321         u_short class;
 322         unsigned int ttl;
 323         u_short rdlen;
 324 } NBTNsResource;
 325
 326 #define SizeOfNsRNB                     6
 327 typedef struct {
 328         u_short g:1, ont:2, resv:13;
 329         struct  in_addr addr;
 330 } NBTNsRNB;
 331
 332 static u_char *
 333 AliasHandleResourceNB(
 334     NBTNsResource *q,
 335     char *pmax,
 336                                                            NBTArguments  *nbtarg)
 337 {
 338         NBTNsRNB        *nb;
 339         u_short bcount;
 340
 341         if (q == NULL || (char *)(q + 1) > pmax)
 342                 return(NULL);
 343         /* Check out a length */
 344         bcount = ntohs(q->rdlen);
 345
 346         /* Forward to Resource NB position */
 347         nb = (NBTNsRNB *)((u_char *)q + SizeOfNsResource);
 348
 349         /* Processing all in_addr array */
 350 #ifdef DEBUG
 351         printf("NB rec[%s", inet_ntoa(nbtarg->oldaddr));
 352             printf("->%s, %dbytes] ",inet_ntoa(nbtarg->newaddr ), bcount);
 353 #endif
 354         while ( nb != NULL && bcount != 0 )  {
 355                 if ((char *)(nb + 1) > pmax) {
 356                         nb = NULL;
 357                         break;
 358                 }
 359 #ifdef DEBUG
 360                 printf("<%s>", inet_ntoa(nb->addr) );
 361 #endif
 362                 if (!bcmp(&nbtarg->oldaddr,&nb->addr, sizeof(struct in_addr) ) ) {
 363                         if ( *nbtarg->uh_sum != 0 ) {
 364                 int acc;
 365                 u_short *sptr;
 366
 367                 sptr = (u_short *) &(nb->addr);
 368                 acc = *sptr++;
 369                 acc += *sptr;
 370                 sptr = (u_short *) &(nbtarg->newaddr);
 371                 acc -= *sptr++;
 372                 acc -= *sptr;
 373                 ADJUST_CHECKSUM(acc, *nbtarg->uh_sum);
 374                         }
 375
 376                         nb->addr = nbtarg->newaddr;
 377 #ifdef DEBUG
 378                         printf("O");
 379 #endif
 380                 }
 381 #ifdef DEBUG
 382                  else {
 383                         printf(".");
 384                 }
 385 #endif
 386                 nb=(NBTNsRNB *)((u_char *)nb + SizeOfNsRNB);
 387                 bcount -= SizeOfNsRNB;
 388         }
 389         if (nb == NULL || (char *)(nb + 1) > pmax) {
 390                 nb = NULL;
 391         }
 392
 393         return ((u_char *)nb);
 394 }
 395
 396 #define SizeOfResourceA         6
 397 typedef struct {
 398         struct  in_addr addr;
 399 } NBTNsResourceA;
 400
 401 static u_char *
 402 AliasHandleResourceA(
 403     NBTNsResource *q,
 404     char *pmax,
 405                                                           NBTArguments  *nbtarg)
 406 {
 407         NBTNsResourceA  *a;
 408         u_short bcount;
 409
 410         if (q == NULL || (char *)(q + 1) > pmax)
 411                 return(NULL);
 412
 413         /* Forward to Resource A position */
 414         a = (NBTNsResourceA *)( (u_char *)q + sizeof(NBTNsResource) );
 415
 416         /* Check out of length */
 417         bcount = ntohs(q->rdlen);
 418
 419         /* Processing all in_addr array */
 420 #ifdef DEBUG
 421         printf("Arec [%s", inet_ntoa(nbtarg->oldaddr));
 422         printf("->%s]",inet_ntoa(nbtarg->newaddr ));
 423 #endif
 424         while ( bcount != 0 )  {
 425                 if (a == NULL || (char *)(a + 1) > pmax)
 426                         return(NULL);
 427 #ifdef DEBUG
 428                 printf("..%s", inet_ntoa(a->addr) );
 429 #endif
 430                 if ( !bcmp(&nbtarg->oldaddr, &a->addr, sizeof(struct in_addr) ) ) {
 431                         if ( *nbtarg->uh_sum != 0 ) {
 432                 int acc;
 433                 u_short *sptr;
 434
 435                 sptr = (u_short *) &(a->addr);           /* Old */
 436                 acc = *sptr++;
 437                 acc += *sptr;
 438                 sptr = (u_short *) &nbtarg->newaddr; /* New */
 439                 acc -= *sptr++;
 440                 acc -= *sptr;
 441                 ADJUST_CHECKSUM(acc, *nbtarg->uh_sum);
 442                         }
 443
 444                         a->addr = nbtarg->newaddr;
 445                 }
 446                 a++;    /*XXXX*/
 447                 bcount -= SizeOfResourceA;
 448         }
 449         if (a == NULL || (char *)(a + 1) > pmax)
 450                 a =  NULL;
 451         return ((u_char *)a);
 452 }
 453
 454 typedef struct {
 455         u_short opcode:4, flags:8, resv:4;
 456 } NBTNsResourceNULL;
 457
 458 static u_char *
 459 AliasHandleResourceNULL(
 460     NBTNsResource *q,
 461     char *pmax,
 462                                                              NBTArguments  *nbtarg)
 463 {
 464         NBTNsResourceNULL       *n;
 465         u_short bcount;
 466
 467         if (q == NULL || (char *)(q + 1) > pmax)
 468                 return(NULL);
 469
 470         /* Forward to Resource NULL position */
 471         n = (NBTNsResourceNULL *)( (u_char *)q + sizeof(NBTNsResource) );
 472
 473         /* Check out of length */
 474         bcount = ntohs(q->rdlen);
 475
 476         /* Processing all in_addr array */
 477         while ( bcount != 0 )  {
 478                 if ((char *)(n + 1) > pmax) {
 479                         n = NULL;
 480                         break;
 481                 }
 482                 n++;
 483                 bcount -= sizeof(NBTNsResourceNULL);
 484         }
 485         if ((char *)(n + 1) > pmax)
 486                 n = NULL;
 487
 488         return ((u_char *)n);
 489 }
 490
 491 static u_char *
 492 AliasHandleResourceNS(
 493     NBTNsResource *q,
 494     char *pmax,
 495                                                              NBTArguments  *nbtarg)
 496 {
 497         NBTNsResourceNULL       *n;
 498         u_short bcount;
 499
 500         if (q == NULL || (char *)(q + 1) > pmax)
 501                 return(NULL);
 502
 503         /* Forward to Resource NULL position */
 504         n = (NBTNsResourceNULL *)( (u_char *)q + sizeof(NBTNsResource) );
 505
 506         /* Check out of length */
 507         bcount = ntohs(q->rdlen);
 508
 509         /* Resource Record Name Filed */
 510         q = (NBTNsResource *)AliasHandleName( (u_char *)n, pmax ); /* XXX */
 511
 512         if (q == NULL || (char *)((u_char *)n + bcount) > pmax)
 513                 return(NULL);
 514         else
 515         return ((u_char *)n + bcount);
 516 }
 517
 518 typedef struct {
 519         u_short numnames;
 520 } NBTNsResourceNBSTAT;
 521
 522 static u_char *
 523 AliasHandleResourceNBSTAT(
 524     NBTNsResource *q,
 525     char *pmax,
 526                                                                NBTArguments  *nbtarg)
 527 {
 528         NBTNsResourceNBSTAT     *n;
 529         u_short bcount;
 530
 531         if (q == NULL || (char *)(q + 1) > pmax)
 532                 return(NULL);
 533
 534         /* Forward to Resource NBSTAT position */
 535         n = (NBTNsResourceNBSTAT *)( (u_char *)q + sizeof(NBTNsResource) );
 536
 537         /* Check out of length */
 538         bcount = ntohs(q->rdlen);
 539
 540         if (q == NULL || (char *)((u_char *)n + bcount) > pmax)
 541                 return(NULL);
 542         else
 543         return ((u_char *)n + bcount);
 544 }
 545
 546 static u_char *
 547 AliasHandleResource(
 548     u_short count,
 549                                                         NBTNsResource *q,
 550     char *pmax,
 551     NBTArguments
 552     *nbtarg)
 553 {
 554         while ( count != 0 ) {
 555                 /* Resource Record Name Filed */
 556                 q = (NBTNsResource *)AliasHandleName( (u_char *)q, pmax );
 557
 558                 if (q == NULL || (char *)(q + 1) > pmax)
 559                         break;
 560 #ifdef DEBUG
 561                 printf("type=%02x, count=%d\n", ntohs(q->type), count );
 562 #endif
 563
 564                 /* Type and Class filed */
 565                 switch ( ntohs(q->type) ) {
 566                         case RR_TYPE_NB:
 567                                 q = (NBTNsResource *)AliasHandleResourceNB(
 568                                     q,
 569                                     pmax,
 570                                     nbtarg
 571                                 );
 572                                 break;
 573                         case RR_TYPE_A:
 574                                 q = (NBTNsResource *)AliasHandleResourceA(
 575                                     q,
 576                                     pmax,
 577                                     nbtarg
 578                                 );
 579                                 break;
 580                         case RR_TYPE_NS:
 581                                 q = (NBTNsResource *)AliasHandleResourceNS(
 582                                     q,
 583                                     pmax,
 584                                     nbtarg
 585                                 );
 586                                 break;
 587                         case RR_TYPE_NULL:
 588                                 q = (NBTNsResource *)AliasHandleResourceNULL(
 589                                     q,
 590                                     pmax,
 591                                     nbtarg
 592                                 );
 593                                 break;
 594                         case RR_TYPE_NBSTAT:
 595                                 q = (NBTNsResource *)AliasHandleResourceNBSTAT(
 596                                     q,
 597                                     pmax,
 598                                     nbtarg
 599                                 );
 600                                 break;
 601                         default:
 602 #ifdef DEBUG
 603                                 printf(
 604                                     "\nUnknown Type of Resource %0x\n",
 605                                     ntohs(q->type)
 606                                 );
 607 #endif
 608                                 break;
 609                 }
 610                 count--;
 611         }
 612         fflush(stdout);
 613         return ((u_char *)q);
 614 }
 615
 616 int AliasHandleUdpNbtNS(
 617         struct ip                       *pip,    /* IP packet to examine/patch */
 618         struct alias_link       *link,
 619         struct in_addr          *alias_address,
 620         u_short                         *alias_port,
 621         struct in_addr          *original_address,
 622         u_short                         *original_port )
 623 {
 624     struct udphdr *     uh;
 625         NbtNSHeader       * nsh;
 626         u_char            * p;
 627         char            *pmax;
 628         NBTArguments    nbtarg;
 629
 630         /* Set up Common Parameter */
 631         nbtarg.oldaddr  =       *alias_address;
 632         nbtarg.oldport  =       *alias_port;
 633         nbtarg.newaddr  =       *original_address;
 634         nbtarg.newport  =       *original_port;
 635
 636     /* Calculate data length of UDP packet */
 637     uh =  (struct udphdr *) ((char *) pip + (pip->ip_hl << 2));
 638         nbtarg.uh_sum   =       &(uh->uh_sum);
 639         nsh = (NbtNSHeader *)((char *)uh + (sizeof(struct udphdr)));
 640         p = (u_char *)(nsh + 1);
 641     pmax = (char *)uh + ntohs( uh->uh_ulen );
 642
 643     if ((char *)(nsh + 1) > pmax)
 644         return(-1);
 645
 646 #ifdef DEBUG
 647     printf(" [%s] ID=%02x, op=%01x, flag=%02x, rcode=%01x, qd=%04x"
 648            ", an=%04x, ns=%04x, ar=%04x, [%d]-->",
 649                 nsh->dir ? "Response": "Request",
 650                 nsh->nametrid,
 651                 nsh->opcode,
 652                 nsh->nmflags,
 653                 nsh->rcode,
 654                 ntohs(nsh->qdcount),
 655                 ntohs(nsh->ancount),
 656                 ntohs(nsh->nscount),
 657                 ntohs(nsh->arcount),
 658         (u_char *)p -(u_char *)nsh
 659     );
 660 #endif
 661
 662         /* Question Entries */
 663         if (ntohs(nsh->qdcount) !=0 ) {
 664         p = AliasHandleQuestion(
 665             ntohs(nsh->qdcount),
 666             (NBTNsQuestion *)p,
 667             pmax,
 668             &nbtarg
 669         );
 670         }
 671
 672         /* Answer Resource Records */
 673         if (ntohs(nsh->ancount) !=0 ) {
 674         p = AliasHandleResource(
 675             ntohs(nsh->ancount),
 676             (NBTNsResource *)p,
 677             pmax,
 678             &nbtarg
 679         );
 680         }
 681
 682         /* Authority Resource Recodrs */
 683         if (ntohs(nsh->nscount) !=0 ) {
 684         p = AliasHandleResource(
 685             ntohs(nsh->nscount),
 686             (NBTNsResource *)p,
 687             pmax,
 688             &nbtarg
 689         );
 690         }
 691
 692         /* Additional Resource Recodrs */
 693         if (ntohs(nsh->arcount) !=0 ) {
 694         p = AliasHandleResource(
 695             ntohs(nsh->arcount),
 696             (NBTNsResource *)p,
 697             pmax,
 698             &nbtarg
 699         );
 700         }
 701
 702 #ifdef DEBUG
 703                 PrintRcode(nsh->rcode);
 704 #endif
 705     return ((p == NULL) ? -1 : 0);
 706 }