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