reactos/dll/win32/dhcpcsvc/dhcp/options.c

   1 /*      $OpenBSD: options.c,v 1.15 2004/12/26 03:17:07 deraadt Exp $    */
   2
   3 /* DHCP options parsing and reassembly. */
   4
   5 /*
   6  * Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of The Internet Software Consortium nor the names
  19  *    of its contributors may be used to endorse or promote products derived
  20  *    from this software without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND
  23  * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
  24  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  25  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  26  * DISCLAIMED.  IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR
  27  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  28  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  29  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  30  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  31  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  32  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  33  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * This software has been written for the Internet Software Consortium
  37  * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie
  38  * Enterprises.  To learn more about the Internet Software Consortium,
  39  * see ``http://www.vix.com/isc''.  To learn more about Vixie
  40  * Enterprises, see ``http://www.vix.com''.
  41  */
  42
  43 #define DHCP_OPTION_DATA
  44 #include <rosdhcp.h>
  45
  46 int bad_options = 0;
  47 int bad_options_max = 5;
  48
  49 void    parse_options(struct packet *);
  50 void    parse_option_buffer(struct packet *, unsigned char *, int);
  51 int     store_options(unsigned char *, int, struct tree_cache **,
  52             unsigned char *, int, int, int, int);
  53
  54
  55 /*
  56  * Parse all available options out of the specified packet.
  57  */
  58 void
  59 parse_options(struct packet *packet)
  60 {
  61         /* Initially, zero all option pointers. */
  62         memset(packet->options, 0, sizeof(packet->options));
  63
  64         /* If we don't see the magic cookie, there's nothing to parse. */
  65         if (memcmp(packet->raw->options, DHCP_OPTIONS_COOKIE, 4)) {
  66                 packet->options_valid = 0;
  67                 return;
  68         }
  69
  70         /*
  71          * Go through the options field, up to the end of the packet or
  72          * the End field.
  73          */
  74         parse_option_buffer(packet, &packet->raw->options[4],
  75             packet->packet_length - DHCP_FIXED_NON_UDP - 4);
  76
  77         /*
  78          * If we parsed a DHCP Option Overload option, parse more
  79          * options out of the buffer(s) containing them.
  80          */
  81         if (packet->options_valid &&
  82             packet->options[DHO_DHCP_OPTION_OVERLOAD].data) {
  83                 if (packet->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1)
  84                         parse_option_buffer(packet,
  85                             (unsigned char *)packet->raw->file,
  86                             sizeof(packet->raw->file));
  87                 if (packet->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)
  88                         parse_option_buffer(packet,
  89                             (unsigned char *)packet->raw->sname,
  90                             sizeof(packet->raw->sname));
  91         }
  92 }
  93
  94 /*
  95  * Parse options out of the specified buffer, storing addresses of
  96  * option values in packet->options and setting packet->options_valid if
  97  * no errors are encountered.
  98  */
  99 void
 100 parse_option_buffer(struct packet *packet,
 101     unsigned char *buffer, int length)
 102 {
 103         unsigned char *s, *t, *end = buffer + length;
 104         int len, code;
 105
 106         for (s = buffer; *s != DHO_END && s < end; ) {
 107                 code = s[0];
 108
 109                 /* Pad options don't have a length - just skip them. */
 110                 if (code == DHO_PAD) {
 111                         s++;
 112                         continue;
 113                 }
 114                 if (s + 2 > end) {
 115                         len = 65536;
 116                         goto bogus;
 117                 }
 118
 119                 /*
 120                  * All other fields (except end, see above) have a
 121                  * one-byte length.
 122                  */
 123                 len = s[1];
 124
 125                 /*
 126                  * If the length is outrageous, silently skip the rest,
 127                  * and mark the packet bad. Unfortunately some crappy
 128                  * dhcp servers always seem to give us garbage on the
 129                  * end of a packet. so rather than keep refusing, give
 130                  * up and try to take one after seeing a few without
 131                  * anything good.
 132                  */
 133                 if (s + len + 2 > end) {
 134                     bogus:
 135                         bad_options++;
 136                         warning("option %s (%d) %s.",
 137                             dhcp_options[code].name, len,
 138                             "larger than buffer");
 139                         if (bad_options == bad_options_max) {
 140                                 packet->options_valid = 1;
 141                                 bad_options = 0;
 142                                 warning("Many bogus options seen in offers. "
 143                                     "Taking this offer in spite of bogus "
 144                                     "options - hope for the best!");
 145                         } else {
 146                                 warning("rejecting bogus offer.");
 147                                 packet->options_valid = 0;
 148                         }
 149                         return;
 150                 }
 151                 /*
 152                  * If we haven't seen this option before, just make
 153                  * space for it and copy it there.
 154                  */
 155                 if (!packet->options[code].data) {
 156                         if (!(t = calloc(1, len + 1)))
 157                                 error("Can't allocate storage for option %s.",
 158                                     dhcp_options[code].name);
 159                         /*
 160                          * Copy and NUL-terminate the option (in case
 161                          * it's an ASCII string.
 162                          */
 163                         memcpy(t, &s[2], len);
 164                         t[len] = 0;
 165                         packet->options[code].len = len;
 166                         packet->options[code].data = t;
 167                 } else {
 168                         /*
 169                          * If it's a repeat, concatenate it to whatever
 170                          * we last saw.   This is really only required
 171                          * for clients, but what the heck...
 172                          */
 173                         t = calloc(1, len + packet->options[code].len + 1);
 174                         if (!t) {
 175                                 error("Can't expand storage for option %s.",
 176                                     dhcp_options[code].name);
 177                                 return;
 178                         }
 179                         memcpy(t, packet->options[code].data,
 180                                 packet->options[code].len);
 181                         memcpy(t + packet->options[code].len,
 182                                 &s[2], len);
 183                         packet->options[code].len += len;
 184                         t[packet->options[code].len] = 0;
 185                         free(packet->options[code].data);
 186                         packet->options[code].data = t;
 187                 }
 188                 s += len + 2;
 189         }
 190         packet->options_valid = 1;
 191 }
 192
 193 /*
 194  * cons options into a big buffer, and then split them out into the
 195  * three separate buffers if needed.  This allows us to cons up a set of
 196  * vendor options using the same routine.
 197  */
 198 int
 199 cons_options(struct packet *inpacket, struct dhcp_packet *outpacket,
 200     int mms, struct tree_cache **options,
 201     int overload, /* Overload flags that may be set. */
 202     int terminate, int bootpp, u_int8_t *prl, int prl_len)
 203 {
 204         unsigned char priority_list[300], buffer[4096];
 205         int priority_len, main_buffer_size, mainbufix, bufix;
 206         int option_size, length;
 207
 208         /*
 209          * If the client has provided a maximum DHCP message size, use
 210          * that; otherwise, if it's BOOTP, only 64 bytes; otherwise use
 211          * up to the minimum IP MTU size (576 bytes).
 212          *
 213          * XXX if a BOOTP client specifies a max message size, we will
 214          * honor it.
 215          */
 216         if (!mms &&
 217             inpacket &&
 218             inpacket->options[DHO_DHCP_MAX_MESSAGE_SIZE].data &&
 219             (inpacket->options[DHO_DHCP_MAX_MESSAGE_SIZE].len >=
 220             sizeof(u_int16_t)))
 221                 mms = getUShort(
 222                     inpacket->options[DHO_DHCP_MAX_MESSAGE_SIZE].data);
 223
 224         if (mms)
 225                 main_buffer_size = mms - DHCP_FIXED_LEN;
 226         else if (bootpp)
 227                 main_buffer_size = 64;
 228         else
 229                 main_buffer_size = 576 - DHCP_FIXED_LEN;
 230
 231         if (main_buffer_size > sizeof(buffer))
 232                 main_buffer_size = sizeof(buffer);
 233
 234         /* Preload the option priority list with mandatory options. */
 235         priority_len = 0;
 236         priority_list[priority_len++] = DHO_DHCP_MESSAGE_TYPE;
 237         priority_list[priority_len++] = DHO_DHCP_SERVER_IDENTIFIER;
 238         priority_list[priority_len++] = DHO_DHCP_LEASE_TIME;
 239         priority_list[priority_len++] = DHO_DHCP_MESSAGE;
 240
 241         /*
 242          * If the client has provided a list of options that it wishes
 243          * returned, use it to prioritize.  Otherwise, prioritize based
 244          * on the default priority list.
 245          */
 246         if (inpacket &&
 247             inpacket->options[DHO_DHCP_PARAMETER_REQUEST_LIST].data) {
 248                 int prlen =
 249                     inpacket->options[DHO_DHCP_PARAMETER_REQUEST_LIST].len;
 250                 if (prlen + priority_len > sizeof(priority_list))
 251                         prlen = sizeof(priority_list) - priority_len;
 252
 253                 memcpy(&priority_list[priority_len],
 254                     inpacket->options[DHO_DHCP_PARAMETER_REQUEST_LIST].data,
 255                     prlen);
 256                 priority_len += prlen;
 257                 prl = priority_list;
 258         } else if (prl) {
 259                 if (prl_len + priority_len > sizeof(priority_list))
 260                         prl_len = sizeof(priority_list) - priority_len;
 261
 262                 memcpy(&priority_list[priority_len], prl, prl_len);
 263                 priority_len += prl_len;
 264                 prl = priority_list;
 265         } else {
 266                 memcpy(&priority_list[priority_len],
 267                     dhcp_option_default_priority_list,
 268                     sizeof_dhcp_option_default_priority_list);
 269                 priority_len += sizeof_dhcp_option_default_priority_list;
 270         }
 271
 272         /* Copy the options into the big buffer... */
 273         option_size = store_options(
 274             buffer,
 275             (main_buffer_size - 7 + ((overload & 1) ? DHCP_FILE_LEN : 0) +
 276                 ((overload & 2) ? DHCP_SNAME_LEN : 0)),
 277             options, priority_list, priority_len, main_buffer_size,
 278             (main_buffer_size + ((overload & 1) ? DHCP_FILE_LEN : 0)),
 279             terminate);
 280
 281         /* Put the cookie up front... */
 282         memcpy(outpacket->options, DHCP_OPTIONS_COOKIE, 4);
 283         mainbufix = 4;
 284
 285         /*
 286          * If we're going to have to overload, store the overload option
 287          * at the beginning.  If we can, though, just store the whole
 288          * thing in the packet's option buffer and leave it at that.
 289          */
 290         if (option_size <= main_buffer_size - mainbufix) {
 291                 memcpy(&outpacket->options[mainbufix],
 292                     buffer, option_size);
 293                 mainbufix += option_size;
 294                 if (mainbufix < main_buffer_size)
 295                         outpacket->options[mainbufix++] = DHO_END;
 296                 length = DHCP_FIXED_NON_UDP + mainbufix;
 297         } else {
 298                 outpacket->options[mainbufix++] = DHO_DHCP_OPTION_OVERLOAD;
 299                 outpacket->options[mainbufix++] = 1;
 300                 if (option_size >
 301                     main_buffer_size - mainbufix + DHCP_FILE_LEN)
 302                         outpacket->options[mainbufix++] = 3;
 303                 else
 304                         outpacket->options[mainbufix++] = 1;
 305
 306                 memcpy(&outpacket->options[mainbufix],
 307                     buffer, main_buffer_size - mainbufix);
 308                 bufix = main_buffer_size - mainbufix;
 309                 length = DHCP_FIXED_NON_UDP + mainbufix;
 310                 if (overload & 1) {
 311                         if (option_size - bufix <= DHCP_FILE_LEN) {
 312                                 memcpy(outpacket->file,
 313                                     &buffer[bufix], option_size - bufix);
 314                                 mainbufix = option_size - bufix;
 315                                 if (mainbufix < DHCP_FILE_LEN)
 316                                         outpacket->file[mainbufix++] = (char)DHO_END;
 317                                 while (mainbufix < DHCP_FILE_LEN)
 318                                         outpacket->file[mainbufix++] = (char)DHO_PAD;
 319                         } else {
 320                                 memcpy(outpacket->file,
 321                                     &buffer[bufix], DHCP_FILE_LEN);
 322                                 bufix += DHCP_FILE_LEN;
 323                         }
 324                 }
 325                 if ((overload & 2) && option_size < bufix) {
 326                         memcpy(outpacket->sname,
 327                             &buffer[bufix], option_size - bufix);
 328
 329                         mainbufix = option_size - bufix;
 330                         if (mainbufix < DHCP_SNAME_LEN)
 331                                 outpacket->file[mainbufix++] = (char)DHO_END;
 332                         while (mainbufix < DHCP_SNAME_LEN)
 333                                 outpacket->file[mainbufix++] = (char)DHO_PAD;
 334                 }
 335         }
 336         return (length);
 337 }
 338
 339 /*
 340  * Store all the requested options into the requested buffer.
 341  */
 342 int
 343 store_options(unsigned char *buffer, int buflen, struct tree_cache **options,
 344     unsigned char *priority_list, int priority_len, int first_cutoff,
 345     int second_cutoff, int terminate)
 346 {
 347         int bufix = 0, option_stored[256], i, ix, tto;
 348
 349         /* Zero out the stored-lengths array. */
 350         memset(option_stored, 0, sizeof(option_stored));
 351
 352         /*
 353          * Copy out the options in the order that they appear in the
 354          * priority list...
 355          */
 356         for (i = 0; i < priority_len; i++) {
 357                 /* Code for next option to try to store. */
 358                 int code = priority_list[i];
 359                 int optstart;
 360
 361                 /*
 362                  * Number of bytes left to store (some may already have
 363                  * been stored by a previous pass).
 364                  */
 365                 int length;
 366
 367                 /* If no data is available for this option, skip it. */
 368                 if (!options[code]) {
 369                         continue;
 370                 }
 371
 372                 /*
 373                  * The client could ask for things that are mandatory,
 374                  * in which case we should avoid storing them twice...
 375                  */
 376                 if (option_stored[code])
 377                         continue;
 378                 option_stored[code] = 1;
 379
 380                 /* We should now have a constant length for the option. */
 381                 length = options[code]->len;
 382
 383                 /* Do we add a NUL? */
 384                 if (terminate && dhcp_options[code].format[0] == 't') {
 385                         length++;
 386                         tto = 1;
 387                 } else
 388                         tto = 0;
 389
 390                 /* Try to store the option. */
 391
 392                 /*
 393                  * If the option's length is more than 255, we must
 394                  * store it in multiple hunks.   Store 255-byte hunks
 395                  * first.  However, in any case, if the option data will
 396                  * cross a buffer boundary, split it across that
 397                  * boundary.
 398                  */
 399                 ix = 0;
 400
 401                 optstart = bufix;
 402                 while (length) {
 403                         unsigned char incr = length > 255 ? 255 : length;
 404
 405                         /*
 406                          * If this hunk of the buffer will cross a
 407                          * boundary, only go up to the boundary in this
 408                          * pass.
 409                          */
 410                         if (bufix < first_cutoff &&
 411                             bufix + incr > first_cutoff)
 412                                 incr = first_cutoff - bufix;
 413                         else if (bufix < second_cutoff &&
 414                             bufix + incr > second_cutoff)
 415                                 incr = second_cutoff - bufix;
 416
 417                         /*
 418                          * If this option is going to overflow the
 419                          * buffer, skip it.
 420                          */
 421                         if (bufix + 2 + incr > buflen) {
 422                                 bufix = optstart;
 423                                 break;
 424                         }
 425
 426                         /* Everything looks good - copy it in! */
 427                         buffer[bufix] = code;
 428                         buffer[bufix + 1] = incr;
 429                         if (tto && incr == length) {
 430                                 memcpy(buffer + bufix + 2,
 431                                     options[code]->value + ix, incr - 1);
 432                                 buffer[bufix + 2 + incr - 1] = 0;
 433                         } else
 434                                 memcpy(buffer + bufix + 2,
 435                                     options[code]->value + ix, incr);
 436                         length -= incr;
 437                         ix += incr;
 438                         bufix += 2 + incr;
 439                 }
 440         }
 441         return (bufix);
 442 }
 443
 444 /*
 445  * Format the specified option so that a human can easily read it.
 446  */
 447 char *
 448 pretty_print_option(unsigned int code, unsigned char *data, int len,
 449     int emit_commas, int emit_quotes)
 450 {
 451         static char optbuf[32768]; /* XXX */
 452         int hunksize = 0, numhunk = -1, numelem = 0;
 453         char fmtbuf[32], *op = optbuf;
 454         int i, j, k, opleft = sizeof(optbuf);
 455         unsigned char *dp = data;
 456         struct in_addr foo;
 457         char comma;
 458
 459         /* Code should be between 0 and 255. */
 460         if (code > 255)
 461                 error("pretty_print_option: bad code %d", code);
 462
 463         if (emit_commas)
 464                 comma = ',';
 465         else
 466                 comma = ' ';
 467
 468         /* Figure out the size of the data. */
 469         for (i = 0; dhcp_options[code].format[i]; i++) {
 470                 if (!numhunk) {
 471                         warning("%s: Excess information in format string: %s",
 472                             dhcp_options[code].name,
 473                             &(dhcp_options[code].format[i]));
 474                         break;
 475                 }
 476                 numelem++;
 477                 fmtbuf[i] = dhcp_options[code].format[i];
 478                 switch (dhcp_options[code].format[i]) {
 479                 case 'A':
 480                         --numelem;
 481                         fmtbuf[i] = 0;
 482                         numhunk = 0;
 483                         break;
 484                 case 'X':
 485                         for (k = 0; k < len; k++)
 486                                 if (!isascii(data[k]) ||
 487                                     !isprint(data[k]))
 488                                         break;
 489                         if (k == len) {
 490                                 fmtbuf[i] = 't';
 491                                 numhunk = -2;
 492                         } else {
 493                                 fmtbuf[i] = 'x';
 494                                 hunksize++;
 495                                 comma = ':';
 496                                 numhunk = 0;
 497                         }
 498                         fmtbuf[i + 1] = 0;
 499                         break;
 500                 case 't':
 501                         fmtbuf[i] = 't';
 502                         fmtbuf[i + 1] = 0;
 503                         numhunk = -2;
 504                         break;
 505                 case 'I':
 506                 case 'l':
 507                 case 'L':
 508                         hunksize += 4;
 509                         break;
 510                 case 's':
 511                 case 'S':
 512                         hunksize += 2;
 513                         break;
 514                 case 'b':
 515                 case 'B':
 516                 case 'f':
 517                         hunksize++;
 518                         break;
 519                 case 'e':
 520                         break;
 521                 default:
 522                         warning("%s: garbage in format string: %s",
 523                             dhcp_options[code].name,
 524                             &(dhcp_options[code].format[i]));
 525                         break;
 526                 }
 527         }
 528
 529         /* Check for too few bytes... */
 530         if (hunksize > len) {
 531                 warning("%s: expecting at least %d bytes; got %d",
 532                     dhcp_options[code].name, hunksize, len);
 533                 return ("<error>");
 534         }
 535         /* Check for too many bytes... */
 536         if (numhunk == -1 && hunksize < len)
 537                 warning("%s: %d extra bytes",
 538                     dhcp_options[code].name, len - hunksize);
 539
 540         /* If this is an array, compute its size. */
 541         if (!numhunk)
 542                 numhunk = len / hunksize;
 543         /* See if we got an exact number of hunks. */
 544         if (numhunk > 0 && numhunk * hunksize < len)
 545                 warning("%s: %d extra bytes at end of array",
 546                     dhcp_options[code].name, len - numhunk * hunksize);
 547
 548         /* A one-hunk array prints the same as a single hunk. */
 549         if (numhunk < 0)
 550                 numhunk = 1;
 551
 552         /* Cycle through the array (or hunk) printing the data. */
 553         for (i = 0; i < numhunk; i++) {
 554                 for (j = 0; j < numelem; j++) {
 555                         int opcount;
 556                         switch (fmtbuf[j]) {
 557                         case 't':
 558                                 if (emit_quotes) {
 559                                         *op++ = '"';
 560                                         opleft--;
 561                                 }
 562                                 for (; dp < data + len; dp++) {
 563                                         if (!isascii(*dp) ||
 564                                             !isprint(*dp)) {
 565                                                 if (dp + 1 != data + len ||
 566                                                     *dp != 0) {
 567                                                         _snprintf(op, opleft,
 568                                                             "\\%03o", *dp);
 569                                                         op += 4;
 570                                                         opleft -= 4;
 571                                                 }
 572                                         } else if (*dp == '"' ||
 573                                             *dp == '\'' ||
 574                                             *dp == '$' ||
 575                                             *dp == '`' ||
 576                                             *dp == '\\') {
 577                                                 *op++ = '\\';
 578                                                 *op++ = *dp;
 579                                                 opleft -= 2;
 580                                         } else {
 581                                                 *op++ = *dp;
 582                                                 opleft--;
 583                                         }
 584                                 }
 585                                 if (emit_quotes) {
 586                                         *op++ = '"';
 587                                         opleft--;
 588                                 }
 589
 590                                 *op = 0;
 591                                 break;
 592                         case 'I':
 593                                 foo.s_addr = htonl(getULong(dp));
 594                                 strncpy(op, inet_ntoa(foo), opleft - 1);
 595                                 op[opleft - 1] = ANSI_NULL;
 596                                 opcount = strlen(op);
 597                                 if (opcount >= opleft)
 598                                         goto toobig;
 599                                 opleft -= opcount;
 600                                 dp += 4;
 601                                 break;
 602                         case 'l':
 603                                 opcount = _snprintf(op, opleft, "%ld",
 604                                     (long)getLong(dp));
 605                                 if (opcount >= opleft || opcount == -1)
 606                                         goto toobig;
 607                                 opleft -= opcount;
 608                                 dp += 4;
 609                                 break;
 610                         case 'L':
 611                                 opcount = _snprintf(op, opleft, "%ld",
 612                                     (unsigned long)getULong(dp));
 613                                 if (opcount >= opleft || opcount == -1)
 614                                         goto toobig;
 615                                 opleft -= opcount;
 616                                 dp += 4;
 617                                 break;
 618                         case 's':
 619                                 opcount = _snprintf(op, opleft, "%d",
 620                                     getShort(dp));
 621                                 if (opcount >= opleft || opcount == -1)
 622                                         goto toobig;
 623                                 opleft -= opcount;
 624                                 dp += 2;
 625                                 break;
 626                         case 'S':
 627                                 opcount = _snprintf(op, opleft, "%d",
 628                                     getUShort(dp));
 629                                 if (opcount >= opleft || opcount == -1)
 630                                         goto toobig;
 631                                 opleft -= opcount;
 632                                 dp += 2;
 633                                 break;
 634                         case 'b':
 635                                 opcount = _snprintf(op, opleft, "%d",
 636                                     *(char *)dp++);
 637                                 if (opcount >= opleft || opcount == -1)
 638                                         goto toobig;
 639                                 opleft -= opcount;
 640                                 break;
 641                         case 'B':
 642                                 opcount = _snprintf(op, opleft, "%d", *dp++);
 643                                 if (opcount >= opleft || opcount == -1)
 644                                         goto toobig;
 645                                 opleft -= opcount;
 646                                 break;
 647                         case 'x':
 648                                 opcount = _snprintf(op, opleft, "%x", *dp++);
 649                                 if (opcount >= opleft || opcount == -1)
 650                                         goto toobig;
 651                                 opleft -= opcount;
 652                                 break;
 653                         case 'f':
 654                                 opcount = (size_t) strncpy(op, *dp++ ? "true" : "false", opleft - 1);
 655                                 op[opleft - 1] = ANSI_NULL;
 656                                 if (opcount >= opleft)
 657                                         goto toobig;
 658                                 opleft -= opcount;
 659                                 break;
 660                         default:
 661                                 warning("Unexpected format code %c", fmtbuf[j]);
 662                         }
 663                         op += strlen(op);
 664                         opleft -= strlen(op);
 665                         if (opleft < 1)
 666                                 goto toobig;
 667                         if (j + 1 < numelem && comma != ':') {
 668                                 *op++ = ' ';
 669                                 opleft--;
 670                         }
 671                 }
 672                 if (i + 1 < numhunk) {
 673                         *op++ = comma;
 674                         opleft--;
 675                 }
 676                 if (opleft < 1)
 677                         goto toobig;
 678
 679         }
 680         return (optbuf);
 681  toobig:
 682         warning("dhcp option too large");
 683         return ("<error>");
 684 }
 685
 686 void
 687 do_packet(struct interface_info *interface, struct dhcp_packet *packet,
 688     int len, unsigned int from_port, struct iaddr from, struct hardware *hfrom)
 689 {
 690         struct packet tp;
 691         int i;
 692
 693         if (packet->hlen > sizeof(packet->chaddr)) {
 694                 note("Discarding packet with invalid hlen.");
 695                 return;
 696         }
 697
 698         memset(&tp, 0, sizeof(tp));
 699         tp.raw = packet;
 700         tp.packet_length = len;
 701         tp.client_port = from_port;
 702         tp.client_addr = from;
 703         tp.interface = interface;
 704         tp.haddr = hfrom;
 705
 706         parse_options(&tp);
 707         if (tp.options_valid &&
 708             tp.options[DHO_DHCP_MESSAGE_TYPE].data)
 709                 tp.packet_type = tp.options[DHO_DHCP_MESSAGE_TYPE].data[0];
 710         if (tp.packet_type)
 711                 dhcp(&tp);
 712         else
 713                 bootp(&tp);
 714
 715         /* Free the data associated with the options. */
 716         for (i = 0; i < 256; i++)
 717                 if (tp.options[i].len && tp.options[i].data)
 718                         free(tp.options[i].data);
 719 }