alias/alias_nbt.c

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   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.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  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.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*-
  23  * Written by Atsushi Murai <amurai@spec.co.jp>
  24  * Copyright (c) 1998, System Planning and Engineering Co.
  25  * All rights reserved.
  26  *
  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.
  35  *
  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.
  47  *
  48  * Based upon:
  49  * $FreeBSD: src/lib/libalias/alias_nbt.c,v 1.4.2.3 2001/08/01 09:52:26 obrien Exp $
  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
  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;
 275                 ADJUST_CHECKSUM(acc, uh->uh_sum);
 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;
 392                 ADJUST_CHECKSUM(acc, *nbtarg->uh_sum);
 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;
 460                 ADJUST_CHECKSUM(acc, *nbtarg->uh_sum);
 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 }