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 * SPDX-License-Identifier: BSD-3-Clause 7 * 8 * Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium. 9 * All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of The Internet Software Consortium nor the names 21 * of its contributors may be used to endorse or promote products derived 22 * from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE INTERNET SOFTWARE CONSORTIUM AND 25 * CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 26 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 27 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 28 * DISCLAIMED. IN NO EVENT SHALL THE INTERNET SOFTWARE CONSORTIUM OR 29 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 32 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 33 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 34 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 35 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * This software has been written for the Internet Software Consortium 39 * by Ted Lemon <mellon@fugue.com> in cooperation with Vixie 40 * Enterprises. To learn more about the Internet Software Consortium, 41 * see ``http://www.vix.com/isc''. To learn more about Vixie 42 * Enterprises, see ``http://www.vix.com''. 43 */ 44 45 #include <sys/cdefs.h> 46 __FBSDID("$FreeBSD$"); 47 48 #include <ctype.h> 49 50 #define DHCP_OPTION_DATA 51 #include "dhcpd.h" 52 53 int bad_options = 0; 54 int bad_options_max = 5; 55 56 void parse_options(struct packet *); 57 void parse_option_buffer(struct packet *, unsigned char *, int); 58 int store_options(unsigned char *, int, struct tree_cache **, 59 unsigned char *, int, int, int, int); 60 void expand_domain_search(struct packet *packet); 61 int find_search_domain_name_len(struct option_data *option, int *offset); 62 void expand_search_domain_name(struct option_data *option, int *offset, 63 unsigned char **domain_search); 64 65 66 /* 67 * Parse all available options out of the specified packet. 68 */ 69 void 70 parse_options(struct packet *packet) 71 { 72 /* Initially, zero all option pointers. */ 73 memset(packet->options, 0, sizeof(packet->options)); 74 75 /* If we don't see the magic cookie, there's nothing to parse. */ 76 if (memcmp(packet->raw->options, DHCP_OPTIONS_COOKIE, 4)) { 77 packet->options_valid = 0; 78 return; 79 } 80 81 /* 82 * Go through the options field, up to the end of the packet or 83 * the End field. 84 */ 85 parse_option_buffer(packet, &packet->raw->options[4], 86 packet->packet_length - DHCP_FIXED_NON_UDP - 4); 87 88 /* 89 * If we parsed a DHCP Option Overload option, parse more 90 * options out of the buffer(s) containing them. 91 */ 92 if (packet->options_valid && 93 packet->options[DHO_DHCP_OPTION_OVERLOAD].data) { 94 if (packet->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 1) 95 parse_option_buffer(packet, 96 (unsigned char *)packet->raw->file, 97 sizeof(packet->raw->file)); 98 if (packet->options[DHO_DHCP_OPTION_OVERLOAD].data[0] & 2) 99 parse_option_buffer(packet, 100 (unsigned char *)packet->raw->sname, 101 sizeof(packet->raw->sname)); 102 } 103 104 /* Expand DHCP Domain Search option. */ 105 if (packet->options_valid) { 106 expand_domain_search(packet); 107 } 108 } 109 110 /* 111 * Parse options out of the specified buffer, storing addresses of 112 * option values in packet->options and setting packet->options_valid if 113 * no errors are encountered. 114 */ 115 void 116 parse_option_buffer(struct packet *packet, 117 unsigned char *buffer, int length) 118 { 119 unsigned char *s, *t, *end = buffer + length; 120 int len, code; 121 122 for (s = buffer; *s != DHO_END && s < end; ) { 123 code = s[0]; 124 125 /* Pad options don't have a length - just skip them. */ 126 if (code == DHO_PAD) { 127 s++; 128 continue; 129 } 130 if (s + 2 > end) { 131 len = 65536; 132 goto bogus; 133 } 134 135 /* 136 * All other fields (except end, see above) have a 137 * one-byte length. 138 */ 139 len = s[1]; 140 141 /* 142 * If the length is outrageous, silently skip the rest, 143 * and mark the packet bad. Unfortunately some crappy 144 * dhcp servers always seem to give us garbage on the 145 * end of a packet. so rather than keep refusing, give 146 * up and try to take one after seeing a few without 147 * anything good. 148 */ 149 if (s + len + 2 > end) { 150 bogus: 151 bad_options++; 152 warning("option %s (%d) %s.", 153 dhcp_options[code].name, len, 154 "larger than buffer"); 155 if (bad_options == bad_options_max) { 156 packet->options_valid = 1; 157 bad_options = 0; 158 warning("Many bogus options seen in offers. " 159 "Taking this offer in spite of bogus " 160 "options - hope for the best!"); 161 } else { 162 warning("rejecting bogus offer."); 163 packet->options_valid = 0; 164 } 165 return; 166 } 167 /* 168 * If we haven't seen this option before, just make 169 * space for it and copy it there. 170 */ 171 if (!packet->options[code].data) { 172 if (!(t = calloc(1, len + 1))) 173 error("Can't allocate storage for option %s.", 174 dhcp_options[code].name); 175 /* 176 * Copy and NUL-terminate the option (in case 177 * it's an ASCII string. 178 */ 179 memcpy(t, &s[2], len); 180 t[len] = 0; 181 packet->options[code].len = len; 182 packet->options[code].data = t; 183 } else { 184 /* 185 * If it's a repeat, concatenate it to whatever 186 * we last saw. This is really only required 187 * for clients, but what the heck... 188 */ 189 t = calloc(1, len + packet->options[code].len + 1); 190 if (!t) 191 error("Can't expand storage for option %s.", 192 dhcp_options[code].name); 193 memcpy(t, packet->options[code].data, 194 packet->options[code].len); 195 memcpy(t + packet->options[code].len, 196 &s[2], len); 197 packet->options[code].len += len; 198 t[packet->options[code].len] = 0; 199 free(packet->options[code].data); 200 packet->options[code].data = t; 201 } 202 s += len + 2; 203 } 204 packet->options_valid = 1; 205 } 206 207 /* 208 * Expand DHCP Domain Search option. The value of this option is 209 * encoded like DNS' list of labels. See: 210 * RFC 3397 211 * RFC 1035 212 */ 213 void 214 expand_domain_search(struct packet *packet) 215 { 216 int offset, expanded_len, next_domain_len; 217 struct option_data *option; 218 unsigned char *domain_search, *cursor; 219 220 if (packet->options[DHO_DOMAIN_SEARCH].data == NULL) 221 return; 222 223 option = &packet->options[DHO_DOMAIN_SEARCH]; 224 225 /* Compute final expanded length. */ 226 expanded_len = 0; 227 offset = 0; 228 while (offset < option->len) { 229 next_domain_len = find_search_domain_name_len(option, &offset); 230 if (next_domain_len < 0) 231 /* The Domain Search option value is invalid. */ 232 return; 233 234 /* We add 1 for the space between domain names. */ 235 expanded_len += next_domain_len + 1; 236 } 237 if (expanded_len > 0) 238 /* Remove 1 for the superfluous trailing space. */ 239 --expanded_len; 240 241 domain_search = malloc(expanded_len + 1); 242 if (domain_search == NULL) 243 error("Can't allocate storage for expanded domain-search\n"); 244 245 offset = 0; 246 cursor = domain_search; 247 while (offset < option->len) { 248 expand_search_domain_name(option, &offset, &cursor); 249 cursor[0] = ' '; 250 cursor++; 251 } 252 domain_search[expanded_len] = '\0'; 253 254 free(option->data); 255 option->len = expanded_len; 256 option->data = domain_search; 257 } 258 259 int 260 find_search_domain_name_len(struct option_data *option, int *offset) 261 { 262 int domain_name_len, i, label_len, pointer, pointed_len; 263 264 domain_name_len = 0; 265 266 i = *offset; 267 while (i < option->len) { 268 label_len = option->data[i]; 269 if (label_len == 0) { 270 /* 271 * A zero-length label marks the end of this 272 * domain name. 273 */ 274 *offset = i + 1; 275 return (domain_name_len); 276 } else if (label_len & 0xC0) { 277 /* This is a pointer to another list of labels. */ 278 if (i + 1 >= option->len) { 279 /* The pointer is truncated. */ 280 warning("Truncated pointer in DHCP Domain " 281 "Search option."); 282 return (-1); 283 } 284 285 pointer = ((label_len & ~(0xC0)) << 8) + 286 option->data[i + 1]; 287 if (pointer >= *offset) { 288 /* 289 * The pointer must indicate a prior 290 * occurrence. 291 */ 292 warning("Invalid forward pointer in DHCP " 293 "Domain Search option compression."); 294 return (-1); 295 } 296 297 pointed_len = find_search_domain_name_len(option, 298 &pointer); 299 domain_name_len += pointed_len; 300 301 *offset = i + 2; 302 return (domain_name_len); 303 } 304 305 if (i + label_len >= option->len) { 306 warning("Truncated label in DHCP Domain Search " 307 "option."); 308 return (-1); 309 } 310 311 /* 312 * Update the domain name length with the length of the 313 * current label, plus a trailing dot ('.'). 314 */ 315 domain_name_len += label_len + 1; 316 317 /* Move cursor. */ 318 i += label_len + 1; 319 } 320 321 warning("Truncated DHCP Domain Search option."); 322 323 return (-1); 324 } 325 326 void 327 expand_search_domain_name(struct option_data *option, int *offset, 328 unsigned char **domain_search) 329 { 330 int i, label_len, pointer; 331 unsigned char *cursor; 332 333 /* 334 * This is the same loop than the function above 335 * (find_search_domain_name_len). Therefore, we remove checks, 336 * they're already done. Here, we just make the copy. 337 */ 338 i = *offset; 339 cursor = *domain_search; 340 while (i < option->len) { 341 label_len = option->data[i]; 342 if (label_len == 0) { 343 /* 344 * A zero-length label marks the end of this 345 * domain name. 346 */ 347 *offset = i + 1; 348 *domain_search = cursor; 349 return; 350 } else if (label_len & 0xC0) { 351 /* This is a pointer to another list of labels. */ 352 pointer = ((label_len & ~(0xC0)) << 8) + 353 option->data[i + 1]; 354 355 expand_search_domain_name(option, &pointer, &cursor); 356 357 *offset = i + 2; 358 *domain_search = cursor; 359 return; 360 } 361 362 /* Copy the label found. */ 363 memcpy(cursor, option->data + i + 1, label_len); 364 cursor[label_len] = '.'; 365 366 /* Move cursor. */ 367 i += label_len + 1; 368 cursor += label_len + 1; 369 } 370 } 371 372 /* 373 * cons options into a big buffer, and then split them out into the 374 * three separate buffers if needed. This allows us to cons up a set of 375 * vendor options using the same routine. 376 */ 377 int 378 cons_options(struct packet *inpacket, struct dhcp_packet *outpacket, 379 int mms, struct tree_cache **options, 380 int overload, /* Overload flags that may be set. */ 381 int terminate, int bootpp, u_int8_t *prl, int prl_len) 382 { 383 unsigned char priority_list[300], buffer[4096]; 384 int priority_len, main_buffer_size, mainbufix, bufix; 385 int option_size, length; 386 387 /* 388 * If the client has provided a maximum DHCP message size, use 389 * that; otherwise, if it's BOOTP, only 64 bytes; otherwise use 390 * up to the minimum IP MTU size (576 bytes). 391 * 392 * XXX if a BOOTP client specifies a max message size, we will 393 * honor it. 394 */ 395 if (!mms && 396 inpacket && 397 inpacket->options[DHO_DHCP_MAX_MESSAGE_SIZE].data && 398 (inpacket->options[DHO_DHCP_MAX_MESSAGE_SIZE].len >= 399 sizeof(u_int16_t))) 400 mms = getUShort( 401 inpacket->options[DHO_DHCP_MAX_MESSAGE_SIZE].data); 402 403 if (mms) 404 main_buffer_size = mms - DHCP_FIXED_LEN; 405 else if (bootpp) 406 main_buffer_size = 64; 407 else 408 main_buffer_size = 576 - DHCP_FIXED_LEN; 409 410 if (main_buffer_size > sizeof(buffer)) 411 main_buffer_size = sizeof(buffer); 412 413 /* Preload the option priority list with mandatory options. */ 414 priority_len = 0; 415 priority_list[priority_len++] = DHO_DHCP_MESSAGE_TYPE; 416 priority_list[priority_len++] = DHO_DHCP_SERVER_IDENTIFIER; 417 priority_list[priority_len++] = DHO_DHCP_LEASE_TIME; 418 priority_list[priority_len++] = DHO_DHCP_MESSAGE; 419 420 /* 421 * If the client has provided a list of options that it wishes 422 * returned, use it to prioritize. Otherwise, prioritize based 423 * on the default priority list. 424 */ 425 if (inpacket && 426 inpacket->options[DHO_DHCP_PARAMETER_REQUEST_LIST].data) { 427 int prlen = 428 inpacket->options[DHO_DHCP_PARAMETER_REQUEST_LIST].len; 429 if (prlen + priority_len > sizeof(priority_list)) 430 prlen = sizeof(priority_list) - priority_len; 431 432 memcpy(&priority_list[priority_len], 433 inpacket->options[DHO_DHCP_PARAMETER_REQUEST_LIST].data, 434 prlen); 435 priority_len += prlen; 436 prl = priority_list; 437 } else if (prl) { 438 if (prl_len + priority_len > sizeof(priority_list)) 439 prl_len = sizeof(priority_list) - priority_len; 440 441 memcpy(&priority_list[priority_len], prl, prl_len); 442 priority_len += prl_len; 443 prl = priority_list; 444 } else { 445 memcpy(&priority_list[priority_len], 446 dhcp_option_default_priority_list, 447 sizeof_dhcp_option_default_priority_list); 448 priority_len += sizeof_dhcp_option_default_priority_list; 449 } 450 451 /* Copy the options into the big buffer... */ 452 option_size = store_options( 453 buffer, 454 (main_buffer_size - 7 + ((overload & 1) ? DHCP_FILE_LEN : 0) + 455 ((overload & 2) ? DHCP_SNAME_LEN : 0)), 456 options, priority_list, priority_len, main_buffer_size, 457 (main_buffer_size + ((overload & 1) ? DHCP_FILE_LEN : 0)), 458 terminate); 459 460 /* Put the cookie up front... */ 461 memcpy(outpacket->options, DHCP_OPTIONS_COOKIE, 4); 462 mainbufix = 4; 463 464 /* 465 * If we're going to have to overload, store the overload option 466 * at the beginning. If we can, though, just store the whole 467 * thing in the packet's option buffer and leave it at that. 468 */ 469 if (option_size <= main_buffer_size - mainbufix) { 470 memcpy(&outpacket->options[mainbufix], 471 buffer, option_size); 472 mainbufix += option_size; 473 if (mainbufix < main_buffer_size) 474 outpacket->options[mainbufix++] = DHO_END; 475 length = DHCP_FIXED_NON_UDP + mainbufix; 476 } else { 477 outpacket->options[mainbufix++] = DHO_DHCP_OPTION_OVERLOAD; 478 outpacket->options[mainbufix++] = 1; 479 if (option_size > 480 main_buffer_size - mainbufix + DHCP_FILE_LEN) 481 outpacket->options[mainbufix++] = 3; 482 else 483 outpacket->options[mainbufix++] = 1; 484 485 memcpy(&outpacket->options[mainbufix], 486 buffer, main_buffer_size - mainbufix); 487 bufix = main_buffer_size - mainbufix; 488 length = DHCP_FIXED_NON_UDP + mainbufix; 489 if (overload & 1) { 490 if (option_size - bufix <= DHCP_FILE_LEN) { 491 memcpy(outpacket->file, 492 &buffer[bufix], option_size - bufix); 493 mainbufix = option_size - bufix; 494 if (mainbufix < DHCP_FILE_LEN) 495 outpacket->file[mainbufix++] = (char)DHO_END; 496 while (mainbufix < DHCP_FILE_LEN) 497 outpacket->file[mainbufix++] = (char)DHO_PAD; 498 } else { 499 memcpy(outpacket->file, 500 &buffer[bufix], DHCP_FILE_LEN); 501 bufix += DHCP_FILE_LEN; 502 } 503 } 504 if ((overload & 2) && option_size < bufix) { 505 memcpy(outpacket->sname, 506 &buffer[bufix], option_size - bufix); 507 508 mainbufix = option_size - bufix; 509 if (mainbufix < DHCP_SNAME_LEN) 510 outpacket->file[mainbufix++] = (char)DHO_END; 511 while (mainbufix < DHCP_SNAME_LEN) 512 outpacket->file[mainbufix++] = (char)DHO_PAD; 513 } 514 } 515 return (length); 516 } 517 518 /* 519 * Store all the requested options into the requested buffer. 520 */ 521 int 522 store_options(unsigned char *buffer, int buflen, struct tree_cache **options, 523 unsigned char *priority_list, int priority_len, int first_cutoff, 524 int second_cutoff, int terminate) 525 { 526 int bufix = 0, option_stored[256], i, ix, tto; 527 528 /* Zero out the stored-lengths array. */ 529 memset(option_stored, 0, sizeof(option_stored)); 530 531 /* 532 * Copy out the options in the order that they appear in the 533 * priority list... 534 */ 535 for (i = 0; i < priority_len; i++) { 536 /* Code for next option to try to store. */ 537 int code = priority_list[i]; 538 int optstart; 539 540 /* 541 * Number of bytes left to store (some may already have 542 * been stored by a previous pass). 543 */ 544 int length; 545 546 /* If no data is available for this option, skip it. */ 547 if (!options[code]) { 548 continue; 549 } 550 551 /* 552 * The client could ask for things that are mandatory, 553 * in which case we should avoid storing them twice... 554 */ 555 if (option_stored[code]) 556 continue; 557 option_stored[code] = 1; 558 559 /* We should now have a constant length for the option. */ 560 length = options[code]->len; 561 562 /* Do we add a NUL? */ 563 if (terminate && dhcp_options[code].format[0] == 't') { 564 length++; 565 tto = 1; 566 } else 567 tto = 0; 568 569 /* Try to store the option. */ 570 571 /* 572 * If the option's length is more than 255, we must 573 * store it in multiple hunks. Store 255-byte hunks 574 * first. However, in any case, if the option data will 575 * cross a buffer boundary, split it across that 576 * boundary. 577 */ 578 ix = 0; 579 580 optstart = bufix; 581 while (length) { 582 unsigned char incr = length > 255 ? 255 : length; 583 584 /* 585 * If this hunk of the buffer will cross a 586 * boundary, only go up to the boundary in this 587 * pass. 588 */ 589 if (bufix < first_cutoff && 590 bufix + incr > first_cutoff) 591 incr = first_cutoff - bufix; 592 else if (bufix < second_cutoff && 593 bufix + incr > second_cutoff) 594 incr = second_cutoff - bufix; 595 596 /* 597 * If this option is going to overflow the 598 * buffer, skip it. 599 */ 600 if (bufix + 2 + incr > buflen) { 601 bufix = optstart; 602 break; 603 } 604 605 /* Everything looks good - copy it in! */ 606 buffer[bufix] = code; 607 buffer[bufix + 1] = incr; 608 if (tto && incr == length) { 609 memcpy(buffer + bufix + 2, 610 options[code]->value + ix, incr - 1); 611 buffer[bufix + 2 + incr - 1] = 0; 612 } else 613 memcpy(buffer + bufix + 2, 614 options[code]->value + ix, incr); 615 length -= incr; 616 ix += incr; 617 bufix += 2 + incr; 618 } 619 } 620 return (bufix); 621 } 622 623 /* 624 * Format the specified option so that a human can easily read it. 625 */ 626 char * 627 pretty_print_option(unsigned int code, unsigned char *data, int len, 628 int emit_commas, int emit_quotes) 629 { 630 static char optbuf[32768]; /* XXX */ 631 int hunksize = 0, numhunk = -1, numelem = 0; 632 char fmtbuf[32], *op = optbuf; 633 int i, j, k, opleft = sizeof(optbuf); 634 unsigned char *dp = data; 635 struct in_addr foo; 636 char comma; 637 638 /* Code should be between 0 and 255. */ 639 if (code > 255) 640 error("pretty_print_option: bad code %d", code); 641 642 if (emit_commas) 643 comma = ','; 644 else 645 comma = ' '; 646 647 /* Figure out the size of the data. */ 648 for (i = 0; dhcp_options[code].format[i]; i++) { 649 if (!numhunk) { 650 warning("%s: Excess information in format string: %s", 651 dhcp_options[code].name, 652 &(dhcp_options[code].format[i])); 653 break; 654 } 655 numelem++; 656 fmtbuf[i] = dhcp_options[code].format[i]; 657 switch (dhcp_options[code].format[i]) { 658 case 'A': 659 --numelem; 660 fmtbuf[i] = 0; 661 numhunk = 0; 662 break; 663 case 'X': 664 for (k = 0; k < len; k++) 665 if (!isascii(data[k]) || 666 !isprint(data[k])) 667 break; 668 if (k == len) { 669 fmtbuf[i] = 't'; 670 numhunk = -2; 671 } else { 672 fmtbuf[i] = 'x'; 673 hunksize++; 674 comma = ':'; 675 numhunk = 0; 676 } 677 fmtbuf[i + 1] = 0; 678 break; 679 case 't': 680 fmtbuf[i] = 't'; 681 fmtbuf[i + 1] = 0; 682 numhunk = -2; 683 break; 684 case 'I': 685 case 'l': 686 case 'L': 687 hunksize += 4; 688 break; 689 case 's': 690 case 'S': 691 hunksize += 2; 692 break; 693 case 'b': 694 case 'B': 695 case 'f': 696 hunksize++; 697 break; 698 case 'e': 699 break; 700 default: 701 warning("%s: garbage in format string: %s", 702 dhcp_options[code].name, 703 &(dhcp_options[code].format[i])); 704 break; 705 } 706 } 707 708 /* Check for too few bytes... */ 709 if (hunksize > len) { 710 warning("%s: expecting at least %d bytes; got %d", 711 dhcp_options[code].name, hunksize, len); 712 return ("<error>"); 713 } 714 /* Check for too many bytes... */ 715 if (numhunk == -1 && hunksize < len) 716 warning("%s: %d extra bytes", 717 dhcp_options[code].name, len - hunksize); 718 719 /* If this is an array, compute its size. */ 720 if (!numhunk) 721 numhunk = len / hunksize; 722 /* See if we got an exact number of hunks. */ 723 if (numhunk > 0 && numhunk * hunksize < len) 724 warning("%s: %d extra bytes at end of array", 725 dhcp_options[code].name, len - numhunk * hunksize); 726 727 /* A one-hunk array prints the same as a single hunk. */ 728 if (numhunk < 0) 729 numhunk = 1; 730 731 /* Cycle through the array (or hunk) printing the data. */ 732 for (i = 0; i < numhunk; i++) { 733 for (j = 0; j < numelem; j++) { 734 int opcount; 735 switch (fmtbuf[j]) { 736 case 't': 737 if (emit_quotes) { 738 *op++ = '"'; 739 opleft--; 740 } 741 for (; dp < data + len; dp++) { 742 if (!isascii(*dp) || 743 !isprint(*dp)) { 744 if (dp + 1 != data + len || 745 *dp != 0) { 746 snprintf(op, opleft, 747 "\\%03o", *dp); 748 op += 4; 749 opleft -= 4; 750 } 751 } else if (*dp == '"' || 752 *dp == '\'' || 753 *dp == '$' || 754 *dp == '`' || 755 *dp == '\\') { 756 *op++ = '\\'; 757 *op++ = *dp; 758 opleft -= 2; 759 } else { 760 *op++ = *dp; 761 opleft--; 762 } 763 } 764 if (emit_quotes) { 765 *op++ = '"'; 766 opleft--; 767 } 768 769 *op = 0; 770 break; 771 case 'I': 772 foo.s_addr = htonl(getULong(dp)); 773 opcount = strlcpy(op, inet_ntoa(foo), opleft); 774 if (opcount >= opleft) 775 goto toobig; 776 opleft -= opcount; 777 dp += 4; 778 break; 779 case 'l': 780 opcount = snprintf(op, opleft, "%ld", 781 (long)getLong(dp)); 782 if (opcount >= opleft || opcount == -1) 783 goto toobig; 784 opleft -= opcount; 785 dp += 4; 786 break; 787 case 'L': 788 opcount = snprintf(op, opleft, "%lu", 789 (unsigned long)getULong(dp)); 790 if (opcount >= opleft || opcount == -1) 791 goto toobig; 792 opleft -= opcount; 793 dp += 4; 794 break; 795 case 's': 796 opcount = snprintf(op, opleft, "%d", 797 getShort(dp)); 798 if (opcount >= opleft || opcount == -1) 799 goto toobig; 800 opleft -= opcount; 801 dp += 2; 802 break; 803 case 'S': 804 opcount = snprintf(op, opleft, "%u", 805 getUShort(dp)); 806 if (opcount >= opleft || opcount == -1) 807 goto toobig; 808 opleft -= opcount; 809 dp += 2; 810 break; 811 case 'b': 812 opcount = snprintf(op, opleft, "%d", 813 *(char *)dp++); 814 if (opcount >= opleft || opcount == -1) 815 goto toobig; 816 opleft -= opcount; 817 break; 818 case 'B': 819 opcount = snprintf(op, opleft, "%d", *dp++); 820 if (opcount >= opleft || opcount == -1) 821 goto toobig; 822 opleft -= opcount; 823 break; 824 case 'x': 825 opcount = snprintf(op, opleft, "%x", *dp++); 826 if (opcount >= opleft || opcount == -1) 827 goto toobig; 828 opleft -= opcount; 829 break; 830 case 'f': 831 opcount = strlcpy(op, 832 *dp++ ? "true" : "false", opleft); 833 if (opcount >= opleft) 834 goto toobig; 835 opleft -= opcount; 836 break; 837 default: 838 warning("Unexpected format code %c", fmtbuf[j]); 839 } 840 op += strlen(op); 841 opleft -= strlen(op); 842 if (opleft < 1) 843 goto toobig; 844 if (j + 1 < numelem && comma != ':') { 845 *op++ = ' '; 846 opleft--; 847 } 848 } 849 if (i + 1 < numhunk) { 850 *op++ = comma; 851 opleft--; 852 } 853 if (opleft < 1) 854 goto toobig; 855 856 } 857 return (optbuf); 858 toobig: 859 warning("dhcp option too large"); 860 return ("<error>"); 861 } 862 863 void 864 do_packet(struct interface_info *interface, struct dhcp_packet *packet, 865 int len, unsigned int from_port, struct iaddr from, struct hardware *hfrom) 866 { 867 struct packet tp; 868 int i; 869 870 if (packet->hlen > sizeof(packet->chaddr)) { 871 note("Discarding packet with invalid hlen."); 872 return; 873 } 874 875 memset(&tp, 0, sizeof(tp)); 876 tp.raw = packet; 877 tp.packet_length = len; 878 tp.client_port = from_port; 879 tp.client_addr = from; 880 tp.interface = interface; 881 tp.haddr = hfrom; 882 883 parse_options(&tp); 884 if (tp.options_valid && 885 tp.options[DHO_DHCP_MESSAGE_TYPE].data) 886 tp.packet_type = tp.options[DHO_DHCP_MESSAGE_TYPE].data[0]; 887 if (tp.packet_type) 888 dhcp(&tp); 889 else 890 bootp(&tp); 891 892 /* Free the data associated with the options. */ 893 for (i = 0; i < 256; i++) 894 if (tp.options[i].len && tp.options[i].data) 895 free(tp.options[i].data); 896 } 897