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