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; 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 /* We add 1 for the space between domain names. */ 228 expanded_len += 229 find_search_domain_name_len(option, &offset) + 1; 230 } 231 if (expanded_len > 0) 232 /* Remove 1 for the superfluous trailing space. */ 233 --expanded_len; 234 235 domain_search = malloc(expanded_len + 1); 236 if (domain_search == NULL) 237 error("Can't allocate storage for expanded domain-search\n"); 238 239 offset = 0; 240 cursor = domain_search; 241 while (offset < option->len) { 242 expand_search_domain_name(option, &offset, &cursor); 243 cursor[0] = ' '; 244 cursor++; 245 } 246 domain_search[expanded_len] = '\0'; 247 248 free(option->data); 249 option->len = expanded_len; 250 option->data = domain_search; 251 } 252 253 int 254 find_search_domain_name_len(struct option_data *option, int *offset) 255 { 256 int domain_name_len, i, label_len, pointer, pointed_len; 257 258 domain_name_len = 0; 259 260 i = *offset; 261 while (i < option->len) { 262 label_len = option->data[i]; 263 if (label_len == 0) { 264 /* 265 * A zero-length label marks the end of this 266 * domain name. 267 */ 268 *offset = i + 1; 269 return (domain_name_len); 270 } else if (label_len & 0xC0) { 271 /* This is a pointer to another list of labels. */ 272 if (i + 1 >= option->len) { 273 /* The pointer is truncated. */ 274 error("Truncated pointer in DHCP Domain " 275 "Search option."); 276 } 277 278 pointer = ((label_len & ~(0xC0)) << 8) + 279 option->data[i + 1]; 280 if (pointer >= *offset) { 281 /* 282 * The pointer must indicates a prior 283 * occurance. 284 */ 285 error("Invalid forward pointer in DHCP Domain " 286 "Search option compression."); 287 } 288 289 pointed_len = find_search_domain_name_len(option, 290 &pointer); 291 domain_name_len += pointed_len; 292 293 *offset = i + 2; 294 return (domain_name_len); 295 } 296 297 if (i + label_len >= option->len) { 298 error("Truncated label in DHCP Domain Search option."); 299 } 300 301 /* 302 * Update the domain name length with the length of the 303 * current label, plus a trailing dot ('.'). 304 */ 305 domain_name_len += label_len + 1; 306 307 /* Move cursor. */ 308 i += label_len + 1; 309 } 310 311 error("Truncated DHCP Domain Search option."); 312 313 return (0); 314 } 315 316 void 317 expand_search_domain_name(struct option_data *option, int *offset, 318 unsigned char **domain_search) 319 { 320 int i, label_len, pointer; 321 unsigned char *cursor; 322 323 /* 324 * This is the same loop than the function above 325 * (find_search_domain_name_len). Therefore, we remove checks, 326 * they're already done. Here, we just make the copy. 327 */ 328 i = *offset; 329 cursor = *domain_search; 330 while (i < option->len) { 331 label_len = option->data[i]; 332 if (label_len == 0) { 333 /* 334 * A zero-length label marks the end of this 335 * domain name. 336 */ 337 *offset = i + 1; 338 *domain_search = cursor; 339 return; 340 } else if (label_len & 0xC0) { 341 /* This is a pointer to another list of labels. */ 342 pointer = ((label_len & ~(0xC0)) << 8) + 343 option->data[i + 1]; 344 345 expand_search_domain_name(option, &pointer, &cursor); 346 347 *offset = i + 2; 348 *domain_search = cursor; 349 return; 350 } 351 352 /* Copy the label found. */ 353 memcpy(cursor, option->data + i + 1, label_len); 354 cursor[label_len] = '.'; 355 356 /* Move cursor. */ 357 i += label_len + 1; 358 cursor += label_len + 1; 359 } 360 } 361 362 /* 363 * cons options into a big buffer, and then split them out into the 364 * three separate buffers if needed. This allows us to cons up a set of 365 * vendor options using the same routine. 366 */ 367 int 368 cons_options(struct packet *inpacket, struct dhcp_packet *outpacket, 369 int mms, struct tree_cache **options, 370 int overload, /* Overload flags that may be set. */ 371 int terminate, int bootpp, u_int8_t *prl, int prl_len) 372 { 373 unsigned char priority_list[300], buffer[4096]; 374 int priority_len, main_buffer_size, mainbufix, bufix; 375 int option_size, length; 376 377 /* 378 * If the client has provided a maximum DHCP message size, use 379 * that; otherwise, if it's BOOTP, only 64 bytes; otherwise use 380 * up to the minimum IP MTU size (576 bytes). 381 * 382 * XXX if a BOOTP client specifies a max message size, we will 383 * honor it. 384 */ 385 if (!mms && 386 inpacket && 387 inpacket->options[DHO_DHCP_MAX_MESSAGE_SIZE].data && 388 (inpacket->options[DHO_DHCP_MAX_MESSAGE_SIZE].len >= 389 sizeof(u_int16_t))) 390 mms = getUShort( 391 inpacket->options[DHO_DHCP_MAX_MESSAGE_SIZE].data); 392 393 if (mms) 394 main_buffer_size = mms - DHCP_FIXED_LEN; 395 else if (bootpp) 396 main_buffer_size = 64; 397 else 398 main_buffer_size = 576 - DHCP_FIXED_LEN; 399 400 if (main_buffer_size > sizeof(buffer)) 401 main_buffer_size = sizeof(buffer); 402 403 /* Preload the option priority list with mandatory options. */ 404 priority_len = 0; 405 priority_list[priority_len++] = DHO_DHCP_MESSAGE_TYPE; 406 priority_list[priority_len++] = DHO_DHCP_SERVER_IDENTIFIER; 407 priority_list[priority_len++] = DHO_DHCP_LEASE_TIME; 408 priority_list[priority_len++] = DHO_DHCP_MESSAGE; 409 410 /* 411 * If the client has provided a list of options that it wishes 412 * returned, use it to prioritize. Otherwise, prioritize based 413 * on the default priority list. 414 */ 415 if (inpacket && 416 inpacket->options[DHO_DHCP_PARAMETER_REQUEST_LIST].data) { 417 int prlen = 418 inpacket->options[DHO_DHCP_PARAMETER_REQUEST_LIST].len; 419 if (prlen + priority_len > sizeof(priority_list)) 420 prlen = sizeof(priority_list) - priority_len; 421 422 memcpy(&priority_list[priority_len], 423 inpacket->options[DHO_DHCP_PARAMETER_REQUEST_LIST].data, 424 prlen); 425 priority_len += prlen; 426 prl = priority_list; 427 } else if (prl) { 428 if (prl_len + priority_len > sizeof(priority_list)) 429 prl_len = sizeof(priority_list) - priority_len; 430 431 memcpy(&priority_list[priority_len], prl, prl_len); 432 priority_len += prl_len; 433 prl = priority_list; 434 } else { 435 memcpy(&priority_list[priority_len], 436 dhcp_option_default_priority_list, 437 sizeof_dhcp_option_default_priority_list); 438 priority_len += sizeof_dhcp_option_default_priority_list; 439 } 440 441 /* Copy the options into the big buffer... */ 442 option_size = store_options( 443 buffer, 444 (main_buffer_size - 7 + ((overload & 1) ? DHCP_FILE_LEN : 0) + 445 ((overload & 2) ? DHCP_SNAME_LEN : 0)), 446 options, priority_list, priority_len, main_buffer_size, 447 (main_buffer_size + ((overload & 1) ? DHCP_FILE_LEN : 0)), 448 terminate); 449 450 /* Put the cookie up front... */ 451 memcpy(outpacket->options, DHCP_OPTIONS_COOKIE, 4); 452 mainbufix = 4; 453 454 /* 455 * If we're going to have to overload, store the overload option 456 * at the beginning. If we can, though, just store the whole 457 * thing in the packet's option buffer and leave it at that. 458 */ 459 if (option_size <= main_buffer_size - mainbufix) { 460 memcpy(&outpacket->options[mainbufix], 461 buffer, option_size); 462 mainbufix += option_size; 463 if (mainbufix < main_buffer_size) 464 outpacket->options[mainbufix++] = DHO_END; 465 length = DHCP_FIXED_NON_UDP + mainbufix; 466 } else { 467 outpacket->options[mainbufix++] = DHO_DHCP_OPTION_OVERLOAD; 468 outpacket->options[mainbufix++] = 1; 469 if (option_size > 470 main_buffer_size - mainbufix + DHCP_FILE_LEN) 471 outpacket->options[mainbufix++] = 3; 472 else 473 outpacket->options[mainbufix++] = 1; 474 475 memcpy(&outpacket->options[mainbufix], 476 buffer, main_buffer_size - mainbufix); 477 bufix = main_buffer_size - mainbufix; 478 length = DHCP_FIXED_NON_UDP + mainbufix; 479 if (overload & 1) { 480 if (option_size - bufix <= DHCP_FILE_LEN) { 481 memcpy(outpacket->file, 482 &buffer[bufix], option_size - bufix); 483 mainbufix = option_size - bufix; 484 if (mainbufix < DHCP_FILE_LEN) 485 outpacket->file[mainbufix++] = (char)DHO_END; 486 while (mainbufix < DHCP_FILE_LEN) 487 outpacket->file[mainbufix++] = (char)DHO_PAD; 488 } else { 489 memcpy(outpacket->file, 490 &buffer[bufix], DHCP_FILE_LEN); 491 bufix += DHCP_FILE_LEN; 492 } 493 } 494 if ((overload & 2) && option_size < bufix) { 495 memcpy(outpacket->sname, 496 &buffer[bufix], option_size - bufix); 497 498 mainbufix = option_size - bufix; 499 if (mainbufix < DHCP_SNAME_LEN) 500 outpacket->file[mainbufix++] = (char)DHO_END; 501 while (mainbufix < DHCP_SNAME_LEN) 502 outpacket->file[mainbufix++] = (char)DHO_PAD; 503 } 504 } 505 return (length); 506 } 507 508 /* 509 * Store all the requested options into the requested buffer. 510 */ 511 int 512 store_options(unsigned char *buffer, int buflen, struct tree_cache **options, 513 unsigned char *priority_list, int priority_len, int first_cutoff, 514 int second_cutoff, int terminate) 515 { 516 int bufix = 0, option_stored[256], i, ix, tto; 517 518 /* Zero out the stored-lengths array. */ 519 memset(option_stored, 0, sizeof(option_stored)); 520 521 /* 522 * Copy out the options in the order that they appear in the 523 * priority list... 524 */ 525 for (i = 0; i < priority_len; i++) { 526 /* Code for next option to try to store. */ 527 int code = priority_list[i]; 528 int optstart; 529 530 /* 531 * Number of bytes left to store (some may already have 532 * been stored by a previous pass). 533 */ 534 int length; 535 536 /* If no data is available for this option, skip it. */ 537 if (!options[code]) { 538 continue; 539 } 540 541 /* 542 * The client could ask for things that are mandatory, 543 * in which case we should avoid storing them twice... 544 */ 545 if (option_stored[code]) 546 continue; 547 option_stored[code] = 1; 548 549 /* We should now have a constant length for the option. */ 550 length = options[code]->len; 551 552 /* Do we add a NUL? */ 553 if (terminate && dhcp_options[code].format[0] == 't') { 554 length++; 555 tto = 1; 556 } else 557 tto = 0; 558 559 /* Try to store the option. */ 560 561 /* 562 * If the option's length is more than 255, we must 563 * store it in multiple hunks. Store 255-byte hunks 564 * first. However, in any case, if the option data will 565 * cross a buffer boundary, split it across that 566 * boundary. 567 */ 568 ix = 0; 569 570 optstart = bufix; 571 while (length) { 572 unsigned char incr = length > 255 ? 255 : length; 573 574 /* 575 * If this hunk of the buffer will cross a 576 * boundary, only go up to the boundary in this 577 * pass. 578 */ 579 if (bufix < first_cutoff && 580 bufix + incr > first_cutoff) 581 incr = first_cutoff - bufix; 582 else if (bufix < second_cutoff && 583 bufix + incr > second_cutoff) 584 incr = second_cutoff - bufix; 585 586 /* 587 * If this option is going to overflow the 588 * buffer, skip it. 589 */ 590 if (bufix + 2 + incr > buflen) { 591 bufix = optstart; 592 break; 593 } 594 595 /* Everything looks good - copy it in! */ 596 buffer[bufix] = code; 597 buffer[bufix + 1] = incr; 598 if (tto && incr == length) { 599 memcpy(buffer + bufix + 2, 600 options[code]->value + ix, incr - 1); 601 buffer[bufix + 2 + incr - 1] = 0; 602 } else 603 memcpy(buffer + bufix + 2, 604 options[code]->value + ix, incr); 605 length -= incr; 606 ix += incr; 607 bufix += 2 + incr; 608 } 609 } 610 return (bufix); 611 } 612 613 /* 614 * Format the specified option so that a human can easily read it. 615 */ 616 char * 617 pretty_print_option(unsigned int code, unsigned char *data, int len, 618 int emit_commas, int emit_quotes) 619 { 620 static char optbuf[32768]; /* XXX */ 621 int hunksize = 0, numhunk = -1, numelem = 0; 622 char fmtbuf[32], *op = optbuf; 623 int i, j, k, opleft = sizeof(optbuf); 624 unsigned char *dp = data; 625 struct in_addr foo; 626 char comma; 627 628 /* Code should be between 0 and 255. */ 629 if (code > 255) 630 error("pretty_print_option: bad code %d", code); 631 632 if (emit_commas) 633 comma = ','; 634 else 635 comma = ' '; 636 637 /* Figure out the size of the data. */ 638 for (i = 0; dhcp_options[code].format[i]; i++) { 639 if (!numhunk) { 640 warning("%s: Excess information in format string: %s", 641 dhcp_options[code].name, 642 &(dhcp_options[code].format[i])); 643 break; 644 } 645 numelem++; 646 fmtbuf[i] = dhcp_options[code].format[i]; 647 switch (dhcp_options[code].format[i]) { 648 case 'A': 649 --numelem; 650 fmtbuf[i] = 0; 651 numhunk = 0; 652 break; 653 case 'X': 654 for (k = 0; k < len; k++) 655 if (!isascii(data[k]) || 656 !isprint(data[k])) 657 break; 658 if (k == len) { 659 fmtbuf[i] = 't'; 660 numhunk = -2; 661 } else { 662 fmtbuf[i] = 'x'; 663 hunksize++; 664 comma = ':'; 665 numhunk = 0; 666 } 667 fmtbuf[i + 1] = 0; 668 break; 669 case 't': 670 fmtbuf[i] = 't'; 671 fmtbuf[i + 1] = 0; 672 numhunk = -2; 673 break; 674 case 'I': 675 case 'l': 676 case 'L': 677 hunksize += 4; 678 break; 679 case 's': 680 case 'S': 681 hunksize += 2; 682 break; 683 case 'b': 684 case 'B': 685 case 'f': 686 hunksize++; 687 break; 688 case 'e': 689 break; 690 default: 691 warning("%s: garbage in format string: %s", 692 dhcp_options[code].name, 693 &(dhcp_options[code].format[i])); 694 break; 695 } 696 } 697 698 /* Check for too few bytes... */ 699 if (hunksize > len) { 700 warning("%s: expecting at least %d bytes; got %d", 701 dhcp_options[code].name, hunksize, len); 702 return ("<error>"); 703 } 704 /* Check for too many bytes... */ 705 if (numhunk == -1 && hunksize < len) 706 warning("%s: %d extra bytes", 707 dhcp_options[code].name, len - hunksize); 708 709 /* If this is an array, compute its size. */ 710 if (!numhunk) 711 numhunk = len / hunksize; 712 /* See if we got an exact number of hunks. */ 713 if (numhunk > 0 && numhunk * hunksize < len) 714 warning("%s: %d extra bytes at end of array", 715 dhcp_options[code].name, len - numhunk * hunksize); 716 717 /* A one-hunk array prints the same as a single hunk. */ 718 if (numhunk < 0) 719 numhunk = 1; 720 721 /* Cycle through the array (or hunk) printing the data. */ 722 for (i = 0; i < numhunk; i++) { 723 for (j = 0; j < numelem; j++) { 724 int opcount; 725 switch (fmtbuf[j]) { 726 case 't': 727 if (emit_quotes) { 728 *op++ = '"'; 729 opleft--; 730 } 731 for (; dp < data + len; dp++) { 732 if (!isascii(*dp) || 733 !isprint(*dp)) { 734 if (dp + 1 != data + len || 735 *dp != 0) { 736 snprintf(op, opleft, 737 "\\%03o", *dp); 738 op += 4; 739 opleft -= 4; 740 } 741 } else if (*dp == '"' || 742 *dp == '\'' || 743 *dp == '$' || 744 *dp == '`' || 745 *dp == '\\') { 746 *op++ = '\\'; 747 *op++ = *dp; 748 opleft -= 2; 749 } else { 750 *op++ = *dp; 751 opleft--; 752 } 753 } 754 if (emit_quotes) { 755 *op++ = '"'; 756 opleft--; 757 } 758 759 *op = 0; 760 break; 761 case 'I': 762 foo.s_addr = htonl(getULong(dp)); 763 opcount = strlcpy(op, inet_ntoa(foo), opleft); 764 if (opcount >= opleft) 765 goto toobig; 766 opleft -= opcount; 767 dp += 4; 768 break; 769 case 'l': 770 opcount = snprintf(op, opleft, "%ld", 771 (long)getLong(dp)); 772 if (opcount >= opleft || opcount == -1) 773 goto toobig; 774 opleft -= opcount; 775 dp += 4; 776 break; 777 case 'L': 778 opcount = snprintf(op, opleft, "%ld", 779 (unsigned long)getULong(dp)); 780 if (opcount >= opleft || opcount == -1) 781 goto toobig; 782 opleft -= opcount; 783 dp += 4; 784 break; 785 case 's': 786 opcount = snprintf(op, opleft, "%d", 787 getShort(dp)); 788 if (opcount >= opleft || opcount == -1) 789 goto toobig; 790 opleft -= opcount; 791 dp += 2; 792 break; 793 case 'S': 794 opcount = snprintf(op, opleft, "%d", 795 getUShort(dp)); 796 if (opcount >= opleft || opcount == -1) 797 goto toobig; 798 opleft -= opcount; 799 dp += 2; 800 break; 801 case 'b': 802 opcount = snprintf(op, opleft, "%d", 803 *(char *)dp++); 804 if (opcount >= opleft || opcount == -1) 805 goto toobig; 806 opleft -= opcount; 807 break; 808 case 'B': 809 opcount = snprintf(op, opleft, "%d", *dp++); 810 if (opcount >= opleft || opcount == -1) 811 goto toobig; 812 opleft -= opcount; 813 break; 814 case 'x': 815 opcount = snprintf(op, opleft, "%x", *dp++); 816 if (opcount >= opleft || opcount == -1) 817 goto toobig; 818 opleft -= opcount; 819 break; 820 case 'f': 821 opcount = strlcpy(op, 822 *dp++ ? "true" : "false", opleft); 823 if (opcount >= opleft) 824 goto toobig; 825 opleft -= opcount; 826 break; 827 default: 828 warning("Unexpected format code %c", fmtbuf[j]); 829 } 830 op += strlen(op); 831 opleft -= strlen(op); 832 if (opleft < 1) 833 goto toobig; 834 if (j + 1 < numelem && comma != ':') { 835 *op++ = ' '; 836 opleft--; 837 } 838 } 839 if (i + 1 < numhunk) { 840 *op++ = comma; 841 opleft--; 842 } 843 if (opleft < 1) 844 goto toobig; 845 846 } 847 return (optbuf); 848 toobig: 849 warning("dhcp option too large"); 850 return ("<error>"); 851 } 852 853 void 854 do_packet(struct interface_info *interface, struct dhcp_packet *packet, 855 int len, unsigned int from_port, struct iaddr from, struct hardware *hfrom) 856 { 857 struct packet tp; 858 int i; 859 860 if (packet->hlen > sizeof(packet->chaddr)) { 861 note("Discarding packet with invalid hlen."); 862 return; 863 } 864 865 memset(&tp, 0, sizeof(tp)); 866 tp.raw = packet; 867 tp.packet_length = len; 868 tp.client_port = from_port; 869 tp.client_addr = from; 870 tp.interface = interface; 871 tp.haddr = hfrom; 872 873 parse_options(&tp); 874 if (tp.options_valid && 875 tp.options[DHO_DHCP_MESSAGE_TYPE].data) 876 tp.packet_type = tp.options[DHO_DHCP_MESSAGE_TYPE].data[0]; 877 if (tp.packet_type) 878 dhcp(&tp); 879 else 880 bootp(&tp); 881 882 /* Free the data associated with the options. */ 883 for (i = 0; i < 256; i++) 884 if (tp.options[i].len && tp.options[i].data) 885 free(tp.options[i].data); 886 } 887