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("\n  Format Error.\n");
 125                         break;
 126                 case SRV_ERR:
 127                         printf("\n  Server failure.\n");
 128                         break;
 129                 case IMP_ERR:
 130                         printf("\n  Unsupported request error.\n");
 131                         break;
 132                 case RFS_ERR:
 133                         printf("\n  Refused error.\n");
 134                         break;
 135                 case ACT_ERR:
 136                         printf("\n  Active error.\n");
 137                         break;
 138                 case CFT_ERR:
 139                         printf("\n  Name in conflict error.\n");
 140                         break;
 141                 default:
 142                         printf("\n  \?\?\?=%0x\n", rcode );
 143                         break;
 144         }
 145 }
 146 #endif
 147
 148
 149 /* Handling Name field */
 150 static u_char *AliasHandleName ( u_char *p, char *pmax ) {
 151
 152         u_char *s;
 153         u_char c;
 154         int             compress;
 155
 156         /* Following length field */
 157
 158         if (p == NULL || (char *)p >= pmax)
 159                 return(NULL);
 160
 161         if (*p & 0xc0 ) {
 162                 p = p + 2;
 163                 if ((char *)p > pmax)
 164                         return(NULL);
 165                 return ((u_char *)p);
 166         }
 167         while ( ( *p & 0x3f) != 0x00 ) {
 168                 s = p + 1;
 169                 if ( *p == 0x20 )
 170                         compress = 1;
 171                 else
 172                         compress = 0;
 173
 174                 /* Get next length field */
 175                 p = (u_char *)(p + (*p & 0x3f) + 1);
 176                 if ((char *)p > pmax) {
 177                         p = NULL;
 178                         break;
 179                 }
 180 #ifdef DEBUG
 181                 printf(":");
 182 #endif
 183                 while (s < p) {
 184                         if ( compress == 1 ) {
 185                                 c = (u_char )(((((*s & 0x0f) << 4) | (*(s+1) & 0x0f)) - 0x11));
 186 #ifdef DEBUG
 187                                 if (isprint( c ) )
 188                                         printf("%c", c );
 189                                 else
 190                                         printf("<0x%02x>", c );
 191 #endif
 192                                 s +=2;
 193                         } else {
 194 #ifdef DEBUG
 195                                 printf("%c", *s);
 196 #endif
 197                                 s++;
 198                         }
 199                 }
 200 #ifdef DEBUG
 201                 printf(":");
 202 #endif
 203                 fflush(stdout);
 204     }
 205
 206         /* Set up to out of Name field */
 207         if (p == NULL || (char *)p >= pmax)
 208             p = NULL;
 209         else
 210             p++;
 211         return ((u_char *)p);
 212 }
 213
 214 /*
 215  * NetBios Datagram Handler (IP/UDP)
 216  */
 217 #define DGM_DIRECT_UNIQ         0x10
 218 #define DGM_DIRECT_GROUP        0x11
 219 #define DGM_BROADCAST           0x12
 220 #define DGM_ERROR                       0x13
 221 #define DGM_QUERY                       0x14
 222 #define DGM_POSITIVE_RES        0x15
 223 #define DGM_NEGATIVE_RES        0x16
 224
 225 int AliasHandleUdpNbt(
 226         struct ip                       *pip,    /* IP packet to examine/patch */
 227         struct alias_link       *link,
 228         struct in_addr          *alias_address,
 229     u_short             alias_port
 230 ) {
 231     struct udphdr *     uh;
 232     NbtDataHeader       *ndh;
 233     u_char              *p = NULL;
 234     char                *pmax;
 235
 236     /* Calculate data length of UDP packet */
 237     uh =  (struct udphdr *) ((char *) pip + (pip->ip_hl << 2));
 238     pmax = (char *)uh + ntohs( uh->uh_ulen );
 239
 240         ndh = (NbtDataHeader *)((char *)uh + (sizeof (struct udphdr)));
 241     if ((char *)(ndh + 1) > pmax)
 242             return(-1);
 243 #ifdef DEBUG
 244         printf("Type=%02x,", ndh->type );
 245 #endif
 246         switch ( ndh->type ) {
 247                 case DGM_DIRECT_UNIQ:
 248                 case DGM_DIRECT_GROUP:
 249                 case DGM_BROADCAST:
 250                         p = (u_char *)ndh + 14;
 251                     p = AliasHandleName ( p, pmax ); /* Source Name */
 252                     p = AliasHandleName ( p, pmax ); /* Destination Name */
 253                         break;
 254                 case DGM_ERROR:
 255                         p = (u_char *)ndh + 11;
 256                         break;
 257                 case DGM_QUERY:
 258                 case DGM_POSITIVE_RES:
 259                 case DGM_NEGATIVE_RES:
 260                         p = (u_char *)ndh + 10;
 261                     p = AliasHandleName ( p, pmax ); /* Destination Name */
 262                         break;
 263         }
 264     if (p == NULL || (char *)p > pmax)
 265             p = NULL;
 266 #ifdef DEBUG
 267         printf("%s:%d-->", inet_ntoa(ndh->source_ip), ntohs(ndh->source_port) );
 268 #endif
 269         /* Doing a IP address and Port number Translation */
 270         if ( uh->uh_sum != 0 ) {
 271                 int                             acc;
 272                 u_short                 *sptr;
 273                 acc  = ndh->source_port;
 274                 acc -= alias_port;
 275                 sptr = (u_short *) &(ndh->source_ip);
 276                 acc += *sptr++;
 277                 acc += *sptr;
 278                 sptr = (u_short *) alias_address;
 279                 acc -= *sptr++;
 280                 acc -= *sptr;
 281                 ADJUST_CHECKSUM(acc, uh->uh_sum);
 282         }
 283     ndh->source_ip = *alias_address;
 284     ndh->source_port = alias_port;
 285 #ifdef DEBUG
 286         printf("%s:%d\n", inet_ntoa(ndh->source_ip), ntohs(ndh->source_port) );
 287         fflush(stdout);
 288 #endif
 289     return((p == NULL) ? -1 : 0);
 290 }
 291 /* Question Section */
 292 #define QS_TYPE_NB              0x0020
 293 #define QS_TYPE_NBSTAT  0x0021
 294 #define QS_CLAS_IN              0x0001
 295 typedef struct {
 296         u_short type;   /* The type of Request */
 297         u_short class;  /* The class of Request */
 298 } NBTNsQuestion;
 299
 300 static u_char *
 301 AliasHandleQuestion(
 302     u_short count,
 303                                                         NBTNsQuestion *q,
 304     char *pmax,
 305                                                         NBTArguments  *nbtarg)
 306 {
 307
 308         while ( count != 0 ) {
 309                 /* Name Filed */
 310                 q = (NBTNsQuestion *)AliasHandleName((u_char *)q, pmax);
 311
 312                 if (q == NULL || (char *)(q + 1) > pmax) {
 313                         q = NULL;
 314                         break;
 315                 }
 316
 317                 /* Type and Class filed */
 318                 switch ( ntohs(q->type) ) {
 319                         case QS_TYPE_NB:
 320                         case QS_TYPE_NBSTAT:
 321                                 q= q+1;
 322                         break;
 323                         default:
 324 #ifdef DEBUG
 325                                 printf("\nUnknown Type on Question %0x\n", ntohs(q->type) );
 326 #endif
 327                         break;
 328                 }
 329                 count--;
 330         }
 331
 332         /* Set up to out of Question Section */
 333         return ((u_char *)q);
 334 }
 335
 336 /* Resource Record */
 337 #define RR_TYPE_A               0x0001
 338 #define RR_TYPE_NS              0x0002
 339 #define RR_TYPE_NULL    0x000a
 340 #define RR_TYPE_NB              0x0020
 341 #define RR_TYPE_NBSTAT  0x0021
 342 #define RR_CLAS_IN              0x0001
 343 #define SizeOfNsResource        8
 344 typedef struct {
 345         u_short type;
 346         u_short class;
 347         unsigned int ttl;
 348         u_short rdlen;
 349 } NBTNsResource;
 350
 351 #define SizeOfNsRNB                     6
 352 typedef struct {
 353         u_short g:1, ont:2, resv:13;
 354         struct  in_addr addr;
 355 } NBTNsRNB;
 356
 357 static u_char *
 358 AliasHandleResourceNB(
 359     NBTNsResource *q,
 360     char *pmax,
 361                                                            NBTArguments  *nbtarg)
 362 {
 363         NBTNsRNB        *nb;
 364         u_short bcount;
 365
 366         if (q == NULL || (char *)(q + 1) > pmax)
 367                 return(NULL);
 368         /* Check out a length */
 369         bcount = ntohs(q->rdlen);
 370
 371         /* Forward to Resource NB position */
 372         nb = (NBTNsRNB *)((u_char *)q + SizeOfNsResource);
 373
 374         /* Processing all in_addr array */
 375 #ifdef DEBUG
 376         printf("  NB rec[%s", inet_ntoa(nbtarg->oldaddr));
 377             printf("->%s, %d bytes] ",inet_ntoa(nbtarg->newaddr ), bcount);
 378 #endif
 379         while ( nb != NULL && bcount != 0 )  {
 380                 if ((char *)(nb + 1) > pmax) {
 381                         nb = NULL;
 382                         break;
 383                 }
 384 #ifdef DEBUG
 385                 printf("<%s>", inet_ntoa(nb->addr) );
 386 #endif
 387                 if (!bcmp(&nbtarg->oldaddr,&nb->addr, sizeof(struct in_addr) ) ) {
 388                         if ( *nbtarg->uh_sum != 0 ) {
 389                 int acc;
 390                 u_short *sptr;
 391
 392                 sptr = (u_short *) &(nb->addr);
 393                 acc = *sptr++;
 394                 acc += *sptr;
 395                 sptr = (u_short *) &(nbtarg->newaddr);
 396                 acc -= *sptr++;
 397                 acc -= *sptr;
 398                 ADJUST_CHECKSUM(acc, *nbtarg->uh_sum);
 399                         }
 400
 401                         nb->addr = nbtarg->newaddr;
 402 #ifdef DEBUG
 403                         printf("O");
 404 #endif
 405                 }
 406 #ifdef DEBUG
 407                  else {
 408                         printf(".");
 409                 }
 410 #endif
 411                 nb=(NBTNsRNB *)((u_char *)nb + SizeOfNsRNB);
 412                 bcount -= SizeOfNsRNB;
 413         }
 414         if (nb == NULL || (char *)(nb + 1) > pmax) {
 415                 nb = NULL;
 416         }
 417
 418         return ((u_char *)nb);
 419 }
 420
 421 #define SizeOfResourceA         6
 422 typedef struct {
 423         struct  in_addr addr;
 424 } NBTNsResourceA;
 425
 426 static u_char *
 427 AliasHandleResourceA(
 428     NBTNsResource *q,
 429     char *pmax,
 430                                                           NBTArguments  *nbtarg)
 431 {
 432         NBTNsResourceA  *a;
 433         u_short bcount;
 434
 435         if (q == NULL || (char *)(q + 1) > pmax)
 436                 return(NULL);
 437
 438         /* Forward to Resource A position */
 439         a = (NBTNsResourceA *)( (u_char *)q + sizeof(NBTNsResource) );
 440
 441         /* Check out of length */
 442         bcount = ntohs(q->rdlen);
 443
 444         /* Processing all in_addr array */
 445 #ifdef DEBUG
 446         printf("Arec [%s", inet_ntoa(nbtarg->oldaddr));
 447         printf("->%s]",inet_ntoa(nbtarg->newaddr ));
 448 #endif
 449         while ( bcount != 0 )  {
 450                 if (a == NULL || (char *)(a + 1) > pmax)
 451                         return(NULL);
 452 #ifdef DEBUG
 453                 printf("..%s", inet_ntoa(a->addr) );
 454 #endif
 455                 if ( !bcmp(&nbtarg->oldaddr, &a->addr, sizeof(struct in_addr) ) ) {
 456                         if ( *nbtarg->uh_sum != 0 ) {
 457                 int acc;
 458                 u_short *sptr;
 459
 460                 sptr = (u_short *) &(a->addr);           /* Old */
 461                 acc = *sptr++;
 462                 acc += *sptr;
 463                 sptr = (u_short *) &nbtarg->newaddr; /* New */
 464                 acc -= *sptr++;
 465                 acc -= *sptr;
 466                 ADJUST_CHECKSUM(acc, *nbtarg->uh_sum);
 467                         }
 468
 469                         a->addr = nbtarg->newaddr;
 470                 }
 471                 a++;    /*XXXX*/
 472                 bcount -= SizeOfResourceA;
 473         }
 474         if (a == NULL || (char *)(a + 1) > pmax)
 475                 a =  NULL;
 476         return ((u_char *)a);
 477 }
 478
 479 typedef struct {
 480         u_short opcode:4, flags:8, resv:4;
 481 } NBTNsResourceNULL;
 482
 483 static u_char *
 484 AliasHandleResourceNULL(
 485     NBTNsResource *q,
 486     char *pmax,
 487                                                              NBTArguments  *nbtarg)
 488 {
 489         NBTNsResourceNULL       *n;
 490         u_short bcount;
 491
 492         if (q == NULL || (char *)(q + 1) > pmax)
 493                 return(NULL);
 494
 495         /* Forward to Resource NULL position */
 496         n = (NBTNsResourceNULL *)( (u_char *)q + sizeof(NBTNsResource) );
 497
 498         /* Check out of length */
 499         bcount = ntohs(q->rdlen);
 500
 501         /* Processing all in_addr array */
 502         while ( bcount != 0 )  {
 503                 if ((char *)(n + 1) > pmax) {
 504                         n = NULL;
 505                         break;
 506                 }
 507                 n++;
 508                 bcount -= sizeof(NBTNsResourceNULL);
 509         }
 510         if ((char *)(n + 1) > pmax)
 511                 n = NULL;
 512
 513         return ((u_char *)n);
 514 }
 515
 516 static u_char *
 517 AliasHandleResourceNS(
 518     NBTNsResource *q,
 519     char *pmax,
 520                                                              NBTArguments  *nbtarg)
 521 {
 522         NBTNsResourceNULL       *n;
 523         u_short bcount;
 524
 525         if (q == NULL || (char *)(q + 1) > pmax)
 526                 return(NULL);
 527
 528         /* Forward to Resource NULL position */
 529         n = (NBTNsResourceNULL *)( (u_char *)q + sizeof(NBTNsResource) );
 530
 531         /* Check out of length */
 532         bcount = ntohs(q->rdlen);
 533
 534         /* Resource Record Name Filed */
 535         q = (NBTNsResource *)AliasHandleName( (u_char *)n, pmax ); /* XXX */
 536
 537         if (q == NULL || (char *)((u_char *)n + bcount) > pmax)
 538                 return(NULL);
 539         else
 540         return ((u_char *)n + bcount);
 541 }
 542
 543 typedef struct {
 544         u_short numnames;
 545 } NBTNsResourceNBSTAT;
 546
 547 static u_char *
 548 AliasHandleResourceNBSTAT(
 549     NBTNsResource *q,
 550     char *pmax,
 551                                                                NBTArguments  *nbtarg)
 552 {
 553         NBTNsResourceNBSTAT     *n;
 554         u_short bcount;
 555
 556         if (q == NULL || (char *)(q + 1) > pmax)
 557                 return(NULL);
 558
 559         /* Forward to Resource NBSTAT position */
 560         n = (NBTNsResourceNBSTAT *)( (u_char *)q + sizeof(NBTNsResource) );
 561
 562         /* Check out of length */
 563         bcount = ntohs(q->rdlen);
 564
 565         if (q == NULL || (char *)((u_char *)n + bcount) > pmax)
 566                 return(NULL);
 567         else
 568         return ((u_char *)n + bcount);
 569 }
 570
 571 static u_char *
 572 AliasHandleResource(
 573     u_short count,
 574                                                         NBTNsResource *q,
 575     char *pmax,
 576     NBTArguments
 577     *nbtarg)
 578 {
 579         while ( count != 0 ) {
 580                 /* Resource Record Name Filed */
 581                 q = (NBTNsResource *)AliasHandleName( (u_char *)q, pmax );
 582
 583                 if (q == NULL || (char *)(q + 1) > pmax)
 584                         break;
 585 #ifdef DEBUG
 586                 printf("\n  type=%02x, count=%d\n", ntohs(q->type), count );
 587 #endif
 588
 589                 /* Type and Class filed */
 590                 switch ( ntohs(q->type) ) {
 591                         case RR_TYPE_NB:
 592                                 q = (NBTNsResource *)AliasHandleResourceNB(
 593                                     q,
 594                                     pmax,
 595                                     nbtarg
 596                                 );
 597                                 break;
 598                         case RR_TYPE_A:
 599                                 q = (NBTNsResource *)AliasHandleResourceA(
 600                                     q,
 601                                     pmax,
 602                                     nbtarg
 603                                 );
 604                                 break;
 605                         case RR_TYPE_NS:
 606                                 q = (NBTNsResource *)AliasHandleResourceNS(
 607                                     q,
 608                                     pmax,
 609                                     nbtarg
 610                                 );
 611                                 break;
 612                         case RR_TYPE_NULL:
 613                                 q = (NBTNsResource *)AliasHandleResourceNULL(
 614                                     q,
 615                                     pmax,
 616                                     nbtarg
 617                                 );
 618                                 break;
 619                         case RR_TYPE_NBSTAT:
 620                                 q = (NBTNsResource *)AliasHandleResourceNBSTAT(
 621                                     q,
 622                                     pmax,
 623                                     nbtarg
 624                                 );
 625                                 break;
 626                         default:
 627 #ifdef DEBUG
 628                                 printf(
 629                                     "\nUnknown Type of Resource %0x\n",
 630                                     ntohs(q->type)
 631                                 );
 632 #endif
 633                                 break;
 634                 }
 635                 count--;
 636         }
 637         fflush(stdout);
 638         return ((u_char *)q);
 639 }
 640
 641 int AliasHandleUdpNbtNS(
 642         struct ip                       *pip,    /* IP packet to examine/patch */
 643         struct alias_link       *link,
 644         struct in_addr          *alias_address,
 645         u_short                         *alias_port,
 646         struct in_addr          *original_address,
 647         u_short                         *original_port )
 648 {
 649     struct udphdr *     uh;
 650         NbtNSHeader       * nsh;
 651         u_char            * p;
 652         char            *pmax;
 653         NBTArguments    nbtarg;
 654
 655         /* Set up Common Parameter */
 656         nbtarg.oldaddr  =       *alias_address;
 657         nbtarg.oldport  =       *alias_port;
 658         nbtarg.newaddr  =       *original_address;
 659         nbtarg.newport  =       *original_port;
 660
 661     /* Calculate data length of UDP packet */
 662     uh =  (struct udphdr *) ((char *) pip + (pip->ip_hl << 2));
 663         nbtarg.uh_sum   =       &(uh->uh_sum);
 664         nsh = (NbtNSHeader *)((char *)uh + (sizeof(struct udphdr)));
 665         p = (u_char *)(nsh + 1);
 666     pmax = (char *)uh + ntohs( uh->uh_ulen );
 667
 668     if ((char *)(nsh + 1) > pmax)
 669         return(-1);
 670
 671 #ifdef DEBUG
 672     printf(" [%s] ID=%02x, op=%01x, flag=%02x, rcode=%01x, qd=%04x"
 673            ", an=%04x, ns=%04x, ar=%04x, [%d]-->",
 674                 nsh->dir ? "Response": "Request",
 675                 nsh->nametrid,
 676                 nsh->opcode,
 677                 nsh->nmflags,
 678                 nsh->rcode,
 679                 ntohs(nsh->qdcount),
 680                 ntohs(nsh->ancount),
 681                 ntohs(nsh->nscount),
 682                 ntohs(nsh->arcount),
 683                 (int)((u_char *)p -(u_char *)nsh)
 684     );
 685 #endif
 686
 687         /* Question Entries */
 688         if (ntohs(nsh->qdcount) !=0 ) {
 689         p = AliasHandleQuestion(
 690             ntohs(nsh->qdcount),
 691             (NBTNsQuestion *)p,
 692             pmax,
 693             &nbtarg
 694         );
 695         }
 696
 697         /* Answer Resource Records */
 698         if (ntohs(nsh->ancount) !=0 ) {
 699         p = AliasHandleResource(
 700             ntohs(nsh->ancount),
 701             (NBTNsResource *)p,
 702             pmax,
 703             &nbtarg
 704         );
 705         }
 706
 707         /* Authority Resource Recodrs */
 708         if (ntohs(nsh->nscount) !=0 ) {
 709         p = AliasHandleResource(
 710             ntohs(nsh->nscount),
 711             (NBTNsResource *)p,
 712             pmax,
 713             &nbtarg
 714         );
 715         }
 716
 717         /* Additional Resource Recodrs */
 718         if (ntohs(nsh->arcount) !=0 ) {
 719         p = AliasHandleResource(
 720             ntohs(nsh->arcount),
 721             (NBTNsResource *)p,
 722             pmax,
 723             &nbtarg
 724         );
 725         }
 726
 727 #ifdef DEBUG
 728         if (nsh->rcode)
 729                 PrintRcode(nsh->rcode);
 730 #endif
 731     return ((p == NULL) ? -1 : 0);
 732 }