sbin/dhclient/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 #include <sys/cdefs.h>
  44 __FBSDID("$FreeBSD$");
  45
  46 #include <ctype.h>
  47
  48 #define DHCP_OPTION_DATA
  49 #include "dhcpd.h"
  50
  51 int bad_options = 0;
  52 int bad_options_max = 5;
  53
  54 void    parse_options(struct packet *);
  55 void    parse_option_buffer(struct packet *, unsigned char *, int);
  56 int     store_options(unsigned char *, int, struct tree_cache **,
  57             unsigned char *, int, int, int, int);
  58 void    expand_domain_search(struct packet *packet);
  59 int     find_search_domain_name_len(struct option_data *option, int *offset);
  60 void    expand_search_domain_name(struct option_data *option, int *offset,
  61             unsigned char **domain_search);
  62
  63
  64 /*
  65  * Parse all available options out of the specified packet.
  66  */
  67 void
  68 parse_options(struct packet *packet)
  69 {
  70         /* Initially, zero all option pointers. */
  71         memset(packet->options, 0, sizeof(packet->options));
  72
  73         /* If we don't see the magic cookie, there's nothing to parse. */
  74         if (memcmp(packet->raw->options, DHCP_OPTIONS_COOKIE, 4)) {
  75                 packet->options_valid = 0;
  76                 return;
  77         }
  78
  79         /*
  80          * Go through the options field, up to the end of the packet or
  81          * the End field.
  82          */
  83         parse_option_buffer(packet, &packet->raw->options[4],
  84             packet->packet_length - DHCP_FIXED_NON_UDP - 4);
  85
  86         /*
  87          * If we parsed a DHCP Option Overload option, parse more
  88          * options out of the buffer(s) containing them.
  89          */
  90         if (packet->options_valid &&
  91             packet->options[DHO_DHCP_OPTION_OVERLOAD].data) {
  92                 if (packet->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1)
  93                         parse_option_buffer(packet,
  94                             (unsigned char *)packet->raw->file,
  95                             sizeof(packet->raw->file));
  96                 if (packet->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2)
  97                         parse_option_buffer(packet,
  98                             (unsigned char *)packet->raw->sname,
  99                             sizeof(packet->raw->sname));
 100         }
 101
 102         /* Expand DHCP Domain Search option. */
 103         if (packet->options_valid) {
 104                 expand_domain_search(packet);
 105         }
 106 }
 107
 108 /*
 109  * Parse options out of the specified buffer, storing addresses of
 110  * option values in packet->options and setting packet->options_valid if
 111  * no errors are encountered.
 112  */
 113 void
 114 parse_option_buffer(struct packet *packet,
 115     unsigned char *buffer, int length)
 116 {
 117         unsigned char *s, *t, *end = buffer + length;
 118         int len, code;
 119
 120         for (s = buffer; *s != DHO_END && s < end; ) {
 121                 code = s[0];
 122
 123                 /* Pad options don't have a length - just skip them. */
 124                 if (code == DHO_PAD) {
 125                         s++;
 126                         continue;
 127                 }
 128                 if (s + 2 > end) {
 129                         len = 65536;
 130                         goto bogus;
 131                 }
 132
 133                 /*
 134                  * All other fields (except end, see above) have a
 135                  * one-byte length.
 136                  */
 137                 len = s[1];
 138
 139                 /*
 140                  * If the length is outrageous, silently skip the rest,
 141                  * and mark the packet bad. Unfortunately some crappy
 142                  * dhcp servers always seem to give us garbage on the
 143                  * end of a packet. so rather than keep refusing, give
 144                  * up and try to take one after seeing a few without
 145                  * anything good.
 146                  */
 147                 if (s + len + 2 > end) {
 148                     bogus:
 149                         bad_options++;
 150                         warning("option %s (%d) %s.",
 151                             dhcp_options[code].name, len,
 152                             "larger than buffer");
 153                         if (bad_options == bad_options_max) {
 154                                 packet->options_valid = 1;
 155                                 bad_options = 0;
 156                                 warning("Many bogus options seen in offers. "
 157                                     "Taking this offer in spite of bogus "
 158                                     "options - hope for the best!");
 159                         } else {
 160                                 warning("rejecting bogus offer.");
 161                                 packet->options_valid = 0;
 162                         }
 163                         return;
 164                 }
 165                 /*
 166                  * If we haven't seen this option before, just make
 167                  * space for it and copy it there.
 168                  */
 169                 if (!packet->options[code].data) {
 170                         if (!(t = calloc(1, len + 1)))
 171                                 error("Can't allocate storage for option %s.",
 172                                     dhcp_options[code].name);
 173                         /*
 174                          * Copy and NUL-terminate the option (in case
 175                          * it's an ASCII string.
 176                          */
 177                         memcpy(t, &s[2], len);
 178                         t[len] = 0;
 179                         packet->options[code].len = len;
 180                         packet->options[code].data = t;
 181                 } else {
 182                         /*
 183                          * If it's a repeat, concatenate it to whatever
 184                          * we last saw.   This is really only required
 185                          * for clients, but what the heck...
 186                          */
 187                         t = calloc(1, len + packet->options[code].len + 1);
 188                         if (!t)
 189                                 error("Can't expand storage for option %s.",
 190                                     dhcp_options[code].name);
 191                         memcpy(t, packet->options[code].data,
 192                                 packet->options[code].len);
 193                         memcpy(t + packet->options[code].len,
 194                                 &s[2], len);
 195                         packet->options[code].len += len;
 196                         t[packet->options[code].len] = 0;
 197                         free(packet->options[code].data);
 198                         packet->options[code].data = t;
 199                 }
 200                 s += len + 2;
 201         }
 202         packet->options_valid = 1;
 203 }
 204
 205 /*
 206  * Expand DHCP Domain Search option. The value of this option is
 207  * encoded like DNS' list of labels. See:
 208  *   RFC 3397
 209  *   RFC 1035
 210  */
 211 void
 212 expand_domain_search(struct packet *packet)
 213 {
 214         int offset, expanded_len, next_domain_len;
 215         struct option_data *option;
 216         unsigned char *domain_search, *cursor;
 217
 218         if (packet->options[DHO_DOMAIN_SEARCH].data == NULL)
 219                 return;
 220
 221         option = &packet->options[DHO_DOMAIN_SEARCH];
 222
 223         /* Compute final expanded length. */
 224         expanded_len = 0;
 225         offset = 0;
 226         while (offset < option->len) {
 227                 next_domain_len = find_search_domain_name_len(option, &offset);
 228                 if (next_domain_len < 0)
 229                         /* The Domain Search option value is invalid. */
 230                         return;
 231
 232                 /* We add 1 for the space between domain names. */
 233                 expanded_len += next_domain_len + 1;
 234         }
 235         if (expanded_len > 0)
 236                 /* Remove 1 for the superfluous trailing space. */
 237                 --expanded_len;
 238
 239         domain_search = malloc(expanded_len + 1);
 240         if (domain_search == NULL)
 241                 error("Can't allocate storage for expanded domain-search\n");
 242
 243         offset = 0;
 244         cursor = domain_search;
 245         while (offset < option->len) {
 246                 expand_search_domain_name(option, &offset, &cursor);
 247                 cursor[0] = ' ';
 248                 cursor++;
 249         }
 250         domain_search[expanded_len] = '\0';
 251
 252         free(option->data);
 253         option->len = expanded_len;
 254         option->data = domain_search;
 255 }
 256
 257 int
 258 find_search_domain_name_len(struct option_data *option, int *offset)
 259 {
 260         int domain_name_len, i, label_len, pointer, pointed_len;
 261
 262         domain_name_len = 0;
 263
 264         i = *offset;
 265         while (i < option->len) {
 266                 label_len = option->data[i];
 267                 if (label_len == 0) {
 268                         /*
 269                          * A zero-length label marks the end of this
 270                          * domain name.
 271                          */
 272                         *offset = i + 1;
 273                         return (domain_name_len);
 274                 } else if (label_len & 0xC0) {
 275                         /* This is a pointer to another list of labels. */
 276                         if (i + 1 >= option->len) {
 277                                 /* The pointer is truncated. */
 278                                 warning("Truncated pointer in DHCP Domain "
 279                                     "Search option.");
 280                                 return (-1);
 281                         }
 282
 283                         pointer = ((label_len & ~(0xC0)) << 8) +
 284                             option->data[i + 1];
 285                         if (pointer >= *offset) {
 286                                 /*
 287                                  * The pointer must indicate a prior
 288                                  * occurrence.
 289                                  */
 290                                 warning("Invalid forward pointer in DHCP "
 291                                     "Domain Search option compression.");
 292                                 return (-1);
 293                         }
 294
 295                         pointed_len = find_search_domain_name_len(option,
 296                             &pointer);
 297                         domain_name_len += pointed_len;
 298
 299                         *offset = i + 2;
 300                         return (domain_name_len);
 301                 }
 302
 303                 if (i + label_len >= option->len) {
 304                         warning("Truncated label in DHCP Domain Search "
 305                             "option.");
 306                         return (-1);
 307                 }
 308
 309                 /*
 310                  * Update the domain name length with the length of the
 311                  * current label, plus a trailing dot ('.').
 312                  */
 313                 domain_name_len += label_len + 1;
 314
 315                 /* Move cursor. */
 316                 i += label_len + 1;
 317         }
 318
 319         warning("Truncated DHCP Domain Search option.");
 320
 321         return (-1);
 322 }
 323
 324 void
 325 expand_search_domain_name(struct option_data *option, int *offset,
 326     unsigned char **domain_search)
 327 {
 328         int i, label_len, pointer;
 329         unsigned char *cursor;
 330
 331         /*
 332          * This is the same loop than the function above
 333          * (find_search_domain_name_len). Therefore, we remove checks,
 334          * they're already done. Here, we just make the copy.
 335          */
 336         i = *offset;
 337         cursor = *domain_search;
 338         while (i < option->len) {
 339                 label_len = option->data[i];
 340                 if (label_len == 0) {
 341                         /*
 342                          * A zero-length label marks the end of this
 343                          * domain name.
 344                          */
 345                         *offset = i + 1;
 346                         *domain_search = cursor;
 347                         return;
 348                 } else if (label_len & 0xC0) {
 349                         /* This is a pointer to another list of labels. */
 350                         pointer = ((label_len & ~(0xC0)) << 8) +
 351                             option->data[i + 1];
 352
 353                         expand_search_domain_name(option, &pointer, &cursor);
 354
 355                         *offset = i + 2;
 356                         *domain_search = cursor;
 357                         return;
 358                 }
 359
 360                 /* Copy the label found. */
 361                 memcpy(cursor, option->data + i + 1, label_len);
 362                 cursor[label_len] = '.';
 363
 364                 /* Move cursor. */
 365                 i += label_len + 1;
 366                 cursor += label_len + 1;
 367         }
 368 }
 369
 370 /*
 371  * cons options into a big buffer, and then split them out into the
 372  * three separate buffers if needed.  This allows us to cons up a set of
 373  * vendor options using the same routine.
 374  */
 375 int
 376 cons_options(struct packet *inpacket, struct dhcp_packet *outpacket,
 377     int mms, struct tree_cache **options,
 378     int overload, /* Overload flags that may be set. */
 379     int terminate, int bootpp, u_int8_t *prl, int prl_len)
 380 {
 381         unsigned char priority_list[300], buffer[4096];
 382         int priority_len, main_buffer_size, mainbufix, bufix;
 383         int option_size, length;
 384
 385         /*
 386          * If the client has provided a maximum DHCP message size, use
 387          * that; otherwise, if it's BOOTP, only 64 bytes; otherwise use
 388          * up to the minimum IP MTU size (576 bytes).
 389          *
 390          * XXX if a BOOTP client specifies a max message size, we will
 391          * honor it.
 392          */
 393         if (!mms &&
 394             inpacket &&
 395             inpacket->options[DHO_DHCP_MAX_MESSAGE_SIZE].data &&
 396             (inpacket->options[DHO_DHCP_MAX_MESSAGE_SIZE].len >=
 397             sizeof(u_int16_t)))
 398                 mms = getUShort(
 399                     inpacket->options[DHO_DHCP_MAX_MESSAGE_SIZE].data);
 400
 401         if (mms)
 402                 main_buffer_size = mms - DHCP_FIXED_LEN;
 403         else if (bootpp)
 404                 main_buffer_size = 64;
 405         else
 406                 main_buffer_size = 576 - DHCP_FIXED_LEN;
 407
 408         if (main_buffer_size > sizeof(buffer))
 409                 main_buffer_size = sizeof(buffer);
 410
 411         /* Preload the option priority list with mandatory options. */
 412         priority_len = 0;
 413         priority_list[priority_len++] = DHO_DHCP_MESSAGE_TYPE;
 414         priority_list[priority_len++] = DHO_DHCP_SERVER_IDENTIFIER;
 415         priority_list[priority_len++] = DHO_DHCP_LEASE_TIME;
 416         priority_list[priority_len++] = DHO_DHCP_MESSAGE;
 417
 418         /*
 419          * If the client has provided a list of options that it wishes
 420          * returned, use it to prioritize.  Otherwise, prioritize based
 421          * on the default priority list.
 422          */
 423         if (inpacket &&
 424             inpacket->options[DHO_DHCP_PARAMETER_REQUEST_LIST].data) {
 425                 int prlen =
 426                     inpacket->options[DHO_DHCP_PARAMETER_REQUEST_LIST].len;
 427                 if (prlen + priority_len > sizeof(priority_list))
 428                         prlen = sizeof(priority_list) - priority_len;
 429
 430                 memcpy(&priority_list[priority_len],
 431                     inpacket->options[DHO_DHCP_PARAMETER_REQUEST_LIST].data,
 432                     prlen);
 433                 priority_len += prlen;
 434                 prl = priority_list;
 435         } else if (prl) {
 436                 if (prl_len + priority_len > sizeof(priority_list))
 437                         prl_len = sizeof(priority_list) - priority_len;
 438
 439                 memcpy(&priority_list[priority_len], prl, prl_len);
 440                 priority_len += prl_len;
 441                 prl = priority_list;
 442         } else {
 443                 memcpy(&priority_list[priority_len],
 444                     dhcp_option_default_priority_list,
 445                     sizeof_dhcp_option_default_priority_list);
 446                 priority_len += sizeof_dhcp_option_default_priority_list;
 447         }
 448
 449         /* Copy the options into the big buffer... */
 450         option_size = store_options(
 451             buffer,
 452             (main_buffer_size - 7 + ((overload & 1) ? DHCP_FILE_LEN : 0) +
 453                 ((overload & 2) ? DHCP_SNAME_LEN : 0)),
 454             options, priority_list, priority_len, main_buffer_size,
 455             (main_buffer_size + ((overload & 1) ? DHCP_FILE_LEN : 0)),
 456             terminate);
 457
 458         /* Put the cookie up front... */
 459         memcpy(outpacket->options, DHCP_OPTIONS_COOKIE, 4);
 460         mainbufix = 4;
 461
 462         /*
 463          * If we're going to have to overload, store the overload option
 464          * at the beginning.  If we can, though, just store the whole
 465          * thing in the packet's option buffer and leave it at that.
 466          */
 467         if (option_size <= main_buffer_size - mainbufix) {
 468                 memcpy(&outpacket->options[mainbufix],
 469                     buffer, option_size);
 470                 mainbufix += option_size;
 471                 if (mainbufix < main_buffer_size)
 472                         outpacket->options[mainbufix++] = DHO_END;
 473                 length = DHCP_FIXED_NON_UDP + mainbufix;
 474         } else {
 475                 outpacket->options[mainbufix++] = DHO_DHCP_OPTION_OVERLOAD;
 476                 outpacket->options[mainbufix++] = 1;
 477                 if (option_size >
 478                     main_buffer_size - mainbufix + DHCP_FILE_LEN)
 479                         outpacket->options[mainbufix++] = 3;
 480                 else
 481                         outpacket->options[mainbufix++] = 1;
 482
 483                 memcpy(&outpacket->options[mainbufix],
 484                     buffer, main_buffer_size - mainbufix);
 485                 bufix = main_buffer_size - mainbufix;
 486                 length = DHCP_FIXED_NON_UDP + mainbufix;
 487                 if (overload & 1) {
 488                         if (option_size - bufix <= DHCP_FILE_LEN) {
 489                                 memcpy(outpacket->file,
 490                                     &buffer[bufix], option_size - bufix);
 491                                 mainbufix = option_size - bufix;
 492                                 if (mainbufix < DHCP_FILE_LEN)
 493                                         outpacket->file[mainbufix++] = (char)DHO_END;
 494                                 while (mainbufix < DHCP_FILE_LEN)
 495                                         outpacket->file[mainbufix++] = (char)DHO_PAD;
 496                         } else {
 497                                 memcpy(outpacket->file,
 498                                     &buffer[bufix], DHCP_FILE_LEN);
 499                                 bufix += DHCP_FILE_LEN;
 500                         }
 501                 }
 502                 if ((overload & 2) && option_size < bufix) {
 503                         memcpy(outpacket->sname,
 504                             &buffer[bufix], option_size - bufix);
 505
 506                         mainbufix = option_size - bufix;
 507                         if (mainbufix < DHCP_SNAME_LEN)
 508                                 outpacket->file[mainbufix++] = (char)DHO_END;
 509                         while (mainbufix < DHCP_SNAME_LEN)
 510                                 outpacket->file[mainbufix++] = (char)DHO_PAD;
 511                 }
 512         }
 513         return (length);
 514 }
 515
 516 /*
 517  * Store all the requested options into the requested buffer.
 518  */
 519 int
 520 store_options(unsigned char *buffer, int buflen, struct tree_cache **options,
 521     unsigned char *priority_list, int priority_len, int first_cutoff,
 522     int second_cutoff, int terminate)
 523 {
 524         int bufix = 0, option_stored[256], i, ix, tto;
 525
 526         /* Zero out the stored-lengths array. */
 527         memset(option_stored, 0, sizeof(option_stored));
 528
 529         /*
 530          * Copy out the options in the order that they appear in the
 531          * priority list...
 532          */
 533         for (i = 0; i < priority_len; i++) {
 534                 /* Code for next option to try to store. */
 535                 int code = priority_list[i];
 536                 int optstart;
 537
 538                 /*
 539                  * Number of bytes left to store (some may already have
 540                  * been stored by a previous pass).
 541                  */
 542                 int length;
 543
 544                 /* If no data is available for this option, skip it. */
 545                 if (!options[code]) {
 546                         continue;
 547                 }
 548
 549                 /*
 550                  * The client could ask for things that are mandatory,
 551                  * in which case we should avoid storing them twice...
 552                  */
 553                 if (option_stored[code])
 554                         continue;
 555                 option_stored[code] = 1;
 556
 557                 /* We should now have a constant length for the option. */
 558                 length = options[code]->len;
 559
 560                 /* Do we add a NUL? */
 561                 if (terminate && dhcp_options[code].format[0] == 't') {
 562                         length++;
 563                         tto = 1;
 564                 } else
 565                         tto = 0;
 566
 567                 /* Try to store the option. */
 568
 569                 /*
 570                  * If the option's length is more than 255, we must
 571                  * store it in multiple hunks.   Store 255-byte hunks
 572                  * first.  However, in any case, if the option data will
 573                  * cross a buffer boundary, split it across that
 574                  * boundary.
 575                  */
 576                 ix = 0;
 577
 578                 optstart = bufix;
 579                 while (length) {
 580                         unsigned char incr = length > 255 ? 255 : length;
 581
 582                         /*
 583                          * If this hunk of the buffer will cross a
 584                          * boundary, only go up to the boundary in this
 585                          * pass.
 586                          */
 587                         if (bufix < first_cutoff &&
 588                             bufix + incr > first_cutoff)
 589                                 incr = first_cutoff - bufix;
 590                         else if (bufix < second_cutoff &&
 591                             bufix + incr > second_cutoff)
 592                                 incr = second_cutoff - bufix;
 593
 594                         /*
 595                          * If this option is going to overflow the
 596                          * buffer, skip it.
 597                          */
 598                         if (bufix + 2 + incr > buflen) {
 599                                 bufix = optstart;
 600                                 break;
 601                         }
 602
 603                         /* Everything looks good - copy it in! */
 604                         buffer[bufix] = code;
 605                         buffer[bufix + 1] = incr;
 606                         if (tto && incr == length) {
 607                                 memcpy(buffer + bufix + 2,
 608                                     options[code]->value + ix, incr - 1);
 609                                 buffer[bufix + 2 + incr - 1] = 0;
 610                         } else
 611                                 memcpy(buffer + bufix + 2,
 612                                     options[code]->value + ix, incr);
 613                         length -= incr;
 614                         ix += incr;
 615                         bufix += 2 + incr;
 616                 }
 617         }
 618         return (bufix);
 619 }
 620
 621 /*
 622  * Format the specified option so that a human can easily read it.
 623  */
 624 char *
 625 pretty_print_option(unsigned int code, unsigned char *data, int len,
 626     int emit_commas, int emit_quotes)
 627 {
 628         static char optbuf[32768]; /* XXX */
 629         int hunksize = 0, numhunk = -1, numelem = 0;
 630         char fmtbuf[32], *op = optbuf;
 631         int i, j, k, opleft = sizeof(optbuf);
 632         unsigned char *dp = data;
 633         struct in_addr foo;
 634         char comma;
 635
 636         /* Code should be between 0 and 255. */
 637         if (code > 255)
 638                 error("pretty_print_option: bad code %d", code);
 639
 640         if (emit_commas)
 641                 comma = ',';
 642         else
 643                 comma = ' ';
 644
 645         /* Figure out the size of the data. */
 646         for (i = 0; dhcp_options[code].format[i]; i++) {
 647                 if (!numhunk) {
 648                         warning("%s: Excess information in format string: %s",
 649                             dhcp_options[code].name,
 650                             &(dhcp_options[code].format[i]));
 651                         break;
 652                 }
 653                 numelem++;
 654                 fmtbuf[i] = dhcp_options[code].format[i];
 655                 switch (dhcp_options[code].format[i]) {
 656                 case 'A':
 657                         --numelem;
 658                         fmtbuf[i] = 0;
 659                         numhunk = 0;
 660                         break;
 661                 case 'X':
 662                         for (k = 0; k < len; k++)
 663                                 if (!isascii(data[k]) ||
 664                                     !isprint(data[k]))
 665                                         break;
 666                         if (k == len) {
 667                                 fmtbuf[i] = 't';
 668                                 numhunk = -2;
 669                         } else {
 670                                 fmtbuf[i] = 'x';
 671                                 hunksize++;
 672                                 comma = ':';
 673                                 numhunk = 0;
 674                         }
 675                         fmtbuf[i + 1] = 0;
 676                         break;
 677                 case 't':
 678                         fmtbuf[i] = 't';
 679                         fmtbuf[i + 1] = 0;
 680                         numhunk = -2;
 681                         break;
 682                 case 'I':
 683                 case 'l':
 684                 case 'L':
 685                         hunksize += 4;
 686                         break;
 687                 case 's':
 688                 case 'S':
 689                         hunksize += 2;
 690                         break;
 691                 case 'b':
 692                 case 'B':
 693                 case 'f':
 694                         hunksize++;
 695                         break;
 696                 case 'e':
 697                         break;
 698                 default:
 699                         warning("%s: garbage in format string: %s",
 700                             dhcp_options[code].name,
 701                             &(dhcp_options[code].format[i]));
 702                         break;
 703                 }
 704         }
 705
 706         /* Check for too few bytes... */
 707         if (hunksize > len) {
 708                 warning("%s: expecting at least %d bytes; got %d",
 709                     dhcp_options[code].name, hunksize, len);
 710                 return ("<error>");
 711         }
 712         /* Check for too many bytes... */
 713         if (numhunk == -1 && hunksize < len)
 714                 warning("%s: %d extra bytes",
 715                     dhcp_options[code].name, len - hunksize);
 716
 717         /* If this is an array, compute its size. */
 718         if (!numhunk)
 719                 numhunk = len / hunksize;
 720         /* See if we got an exact number of hunks. */
 721         if (numhunk > 0 && numhunk * hunksize < len)
 722                 warning("%s: %d extra bytes at end of array",
 723                     dhcp_options[code].name, len - numhunk * hunksize);
 724
 725         /* A one-hunk array prints the same as a single hunk. */
 726         if (numhunk < 0)
 727                 numhunk = 1;
 728
 729         /* Cycle through the array (or hunk) printing the data. */
 730         for (i = 0; i < numhunk; i++) {
 731                 for (j = 0; j < numelem; j++) {
 732                         int opcount;
 733                         switch (fmtbuf[j]) {
 734                         case 't':
 735                                 if (emit_quotes) {
 736                                         *op++ = '"';
 737                                         opleft--;
 738                                 }
 739                                 for (; dp < data + len; dp++) {
 740                                         if (!isascii(*dp) ||
 741                                             !isprint(*dp)) {
 742                                                 if (dp + 1 != data + len ||
 743                                                     *dp != 0) {
 744                                                         snprintf(op, opleft,
 745                                                             "\\%03o", *dp);
 746                                                         op += 4;
 747                                                         opleft -= 4;
 748                                                 }
 749                                         } else if (*dp == '"' ||
 750                                             *dp == '\'' ||
 751                                             *dp == '$' ||
 752                                             *dp == '`' ||
 753                                             *dp == '\\') {
 754                                                 *op++ = '\\';
 755                                                 *op++ = *dp;
 756                                                 opleft -= 2;
 757                                         } else {
 758                                                 *op++ = *dp;
 759                                                 opleft--;
 760                                         }
 761                                 }
 762                                 if (emit_quotes) {
 763                                         *op++ = '"';
 764                                         opleft--;
 765                                 }
 766
 767                                 *op = 0;
 768                                 break;
 769                         case 'I':
 770                                 foo.s_addr = htonl(getULong(dp));
 771                                 opcount = strlcpy(op, inet_ntoa(foo), opleft);
 772                                 if (opcount >= opleft)
 773                                         goto toobig;
 774                                 opleft -= opcount;
 775                                 dp += 4;
 776                                 break;
 777                         case 'l':
 778                                 opcount = snprintf(op, opleft, "%ld",
 779                                     (long)getLong(dp));
 780                                 if (opcount >= opleft || opcount == -1)
 781                                         goto toobig;
 782                                 opleft -= opcount;
 783                                 dp += 4;
 784                                 break;
 785                         case 'L':
 786                                 opcount = snprintf(op, opleft, "%ld",
 787                                     (unsigned long)getULong(dp));
 788                                 if (opcount >= opleft || opcount == -1)
 789                                         goto toobig;
 790                                 opleft -= opcount;
 791                                 dp += 4;
 792                                 break;
 793                         case 's':
 794                                 opcount = snprintf(op, opleft, "%d",
 795                                     getShort(dp));
 796                                 if (opcount >= opleft || opcount == -1)
 797                                         goto toobig;
 798                                 opleft -= opcount;
 799                                 dp += 2;
 800                                 break;
 801                         case 'S':
 802                                 opcount = snprintf(op, opleft, "%d",
 803                                     getUShort(dp));
 804                                 if (opcount >= opleft || opcount == -1)
 805                                         goto toobig;
 806                                 opleft -= opcount;
 807                                 dp += 2;
 808                                 break;
 809                         case 'b':
 810                                 opcount = snprintf(op, opleft, "%d",
 811                                     *(char *)dp++);
 812                                 if (opcount >= opleft || opcount == -1)
 813                                         goto toobig;
 814                                 opleft -= opcount;
 815                                 break;
 816                         case 'B':
 817                                 opcount = snprintf(op, opleft, "%d", *dp++);
 818                                 if (opcount >= opleft || opcount == -1)
 819                                         goto toobig;
 820                                 opleft -= opcount;
 821                                 break;
 822                         case 'x':
 823                                 opcount = snprintf(op, opleft, "%x", *dp++);
 824                                 if (opcount >= opleft || opcount == -1)
 825                                         goto toobig;
 826                                 opleft -= opcount;
 827                                 break;
 828                         case 'f':
 829                                 opcount = strlcpy(op,
 830                                     *dp++ ? "true" : "false", opleft);
 831                                 if (opcount >= opleft)
 832                                         goto toobig;
 833                                 opleft -= opcount;
 834                                 break;
 835                         default:
 836                                 warning("Unexpected format code %c", fmtbuf[j]);
 837                         }
 838                         op += strlen(op);
 839                         opleft -= strlen(op);
 840                         if (opleft < 1)
 841                                 goto toobig;
 842                         if (j + 1 < numelem && comma != ':') {
 843                                 *op++ = ' ';
 844                                 opleft--;
 845                         }
 846                 }
 847                 if (i + 1 < numhunk) {
 848                         *op++ = comma;
 849                         opleft--;
 850                 }
 851                 if (opleft < 1)
 852                         goto toobig;
 853
 854         }
 855         return (optbuf);
 856  toobig:
 857         warning("dhcp option too large");
 858         return ("<error>");
 859 }
 860
 861 void
 862 do_packet(struct interface_info *interface, struct dhcp_packet *packet,
 863     int len, unsigned int from_port, struct iaddr from, struct hardware *hfrom)
 864 {
 865         struct packet tp;
 866         int i;
 867
 868         if (packet->hlen > sizeof(packet->chaddr)) {
 869                 note("Discarding packet with invalid hlen.");
 870                 return;
 871         }
 872
 873         memset(&tp, 0, sizeof(tp));
 874         tp.raw = packet;
 875         tp.packet_length = len;
 876         tp.client_port = from_port;
 877         tp.client_addr = from;
 878         tp.interface = interface;
 879         tp.haddr = hfrom;
 880
 881         parse_options(&tp);
 882         if (tp.options_valid &&
 883             tp.options[DHO_DHCP_MESSAGE_TYPE].data)
 884                 tp.packet_type = tp.options[DHO_DHCP_MESSAGE_TYPE].data[0];
 885         if (tp.packet_type)
 886                 dhcp(&tp);
 887         else
 888                 bootp(&tp);
 889
 890         /* Free the data associated with the options. */
 891         for (i = 0; i < 256; i++)
 892                 if (tp.options[i].len && tp.options[i].data)
 893                         free(tp.options[i].data);
 894 }