1 /* $NetBSD: tftp.c,v 1.4 1997/09/17 16:57:07 drochner Exp $ */ 2 3 /* 4 * Copyright (c) 1996 5 * Matthias Drochner. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed for the NetBSD Project 18 * by Matthias Drochner. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include <sys/cdefs.h> 35 /* 36 * Simple TFTP implementation for libsa. 37 * Assumes: 38 * - socket descriptor (int) at dev->d_opendata, dev stored at 39 * open_file->f_devdata 40 * - server host IP in global rootip 41 * Restrictions: 42 * - read only 43 * - lseek only with SEEK_SET or SEEK_CUR 44 * - no big time differences between transfers (<tftp timeout) 45 */ 46 47 #include <sys/types.h> 48 #include <sys/stat.h> 49 #include <netinet/in.h> 50 #include <netinet/udp.h> 51 #include <netinet/in_systm.h> 52 #include <arpa/tftp.h> 53 54 #include <string.h> 55 56 #include "stand.h" 57 #include "net.h" 58 #include "netif.h" 59 60 #include "tftp.h" 61 62 struct tftp_handle; 63 struct tftprecv_extra; 64 65 static ssize_t recvtftp(struct iodesc *, void **, void **, time_t, void *); 66 static int tftp_open(const char *, struct open_file *); 67 static int tftp_close(struct open_file *); 68 static int tftp_parse_oack(struct tftp_handle *, char *, size_t); 69 static int tftp_read(struct open_file *, void *, size_t, size_t *); 70 static off_t tftp_seek(struct open_file *, off_t, int); 71 static int tftp_set_blksize(struct tftp_handle *, const char *); 72 static int tftp_stat(struct open_file *, struct stat *); 73 static int tftp_preload(struct open_file *); 74 75 struct fs_ops tftp_fsops = { 76 .fs_name = "tftp", 77 .fo_open = tftp_open, 78 .fo_close = tftp_close, 79 .fo_read = tftp_read, 80 .fo_write = null_write, 81 .fo_seek = tftp_seek, 82 .fo_stat = tftp_stat, 83 .fo_preload = tftp_preload, 84 .fo_readdir = null_readdir 85 }; 86 87 static int tftpport = 2000; 88 static int is_open = 0; 89 90 /* 91 * The legacy TFTP_BLKSIZE value was SEGSIZE(512). 92 * TFTP_REQUESTED_BLKSIZE of 1428 is (Ethernet MTU, less the TFTP, UDP and 93 * IP header lengths). 94 */ 95 #define TFTP_REQUESTED_BLKSIZE 1428 96 97 /* 98 * Choose a blksize big enough so we can test with Ethernet 99 * Jumbo frames in the future. 100 */ 101 #define TFTP_MAX_BLKSIZE 9008 102 #define TFTP_TRIES 2 103 104 struct tftp_handle { 105 struct iodesc *iodesc; 106 int currblock; /* contents of lastdata */ 107 unsigned int islastblock:1; /* flag */ 108 unsigned int tries:4; /* number of read attempts */ 109 int validsize; 110 int off; 111 char *path; /* saved for re-requests */ 112 unsigned int tftp_blksize; 113 unsigned long tftp_tsize; 114 void *pkt; 115 struct tftphdr *tftp_hdr; 116 char *tftp_cache; 117 bool lastacksent; 118 }; 119 120 struct tftprecv_extra { 121 struct tftp_handle *tftp_handle; 122 unsigned short rtype; /* Received type */ 123 }; 124 125 #define TFTP_MAX_ERRCODE EOPTNEG 126 static const int tftperrors[TFTP_MAX_ERRCODE + 1] = { 127 0, /* NAK */ 128 ENOENT, 129 EPERM, 130 ENOSPC, 131 EINVAL, /* ??? */ 132 EINVAL, /* ??? */ 133 EEXIST, 134 EINVAL, /* ??? */ 135 EINVAL, /* Option negotiation failed. */ 136 }; 137 138 static int tftp_getnextblock(struct tftp_handle *h); 139 140 /* send error message back. */ 141 static void 142 tftp_senderr(struct tftp_handle *h, u_short errcode, const char *msg) 143 { 144 struct { 145 u_char header[HEADER_SIZE]; 146 struct tftphdr t; 147 u_char space[63]; /* +1 from t */ 148 } __packed __aligned(4) wbuf; 149 char *wtail; 150 int len; 151 152 len = strlen(msg); 153 if (len > sizeof(wbuf.space)) 154 len = sizeof(wbuf.space); 155 156 wbuf.t.th_opcode = htons((u_short)ERROR); 157 wbuf.t.th_code = htons(errcode); 158 159 wtail = wbuf.t.th_msg; 160 bcopy(msg, wtail, len); 161 wtail[len] = '\0'; 162 wtail += len + 1; 163 164 sendudp(h->iodesc, &wbuf.t, wtail - (char *)&wbuf.t); 165 } 166 167 static void 168 tftp_sendack(struct tftp_handle *h, u_short block) 169 { 170 struct { 171 u_char header[HEADER_SIZE]; 172 struct tftphdr t; 173 } __packed __aligned(4) wbuf; 174 char *wtail; 175 176 wbuf.t.th_opcode = htons((u_short)ACK); 177 wtail = (char *)&wbuf.t.th_block; 178 wbuf.t.th_block = htons(block); 179 wtail += 2; 180 181 sendudp(h->iodesc, &wbuf.t, wtail - (char *)&wbuf.t); 182 } 183 184 static ssize_t 185 recvtftp(struct iodesc *d, void **pkt, void **payload, time_t tleft, 186 void *recv_extra) 187 { 188 struct tftprecv_extra *extra; 189 struct tftp_handle *h; 190 struct tftphdr *t; 191 void *ptr = NULL; 192 ssize_t len; 193 int tftp_error; 194 195 errno = 0; 196 extra = recv_extra; 197 h = extra->tftp_handle; 198 199 len = readudp(d, &ptr, (void **)&t, tleft); 200 201 if (len < 4) { 202 free(ptr); 203 return (-1); 204 } 205 206 extra->rtype = ntohs(t->th_opcode); 207 switch (ntohs(t->th_opcode)) { 208 case DATA: { 209 int got; 210 211 if (htons(t->th_block) < (u_short)d->xid) { 212 /* 213 * Apparently our ACK was missed, re-send. 214 */ 215 tftp_sendack(h, htons(t->th_block)); 216 free(ptr); 217 return (-1); 218 } 219 if (htons(t->th_block) != (u_short)d->xid) { 220 /* 221 * Packet from the future, drop this. 222 */ 223 free(ptr); 224 return (-1); 225 } 226 if (d->xid == 1) { 227 /* 228 * First data packet from new port. 229 */ 230 struct udphdr *uh; 231 uh = (struct udphdr *)t - 1; 232 d->destport = uh->uh_sport; 233 } 234 got = len - (t->th_data - (char *)t); 235 *pkt = ptr; 236 *payload = t; 237 return (got); 238 } 239 case ERROR: 240 tftp_error = ntohs(t->th_code); 241 if ((unsigned)tftp_error > TFTP_MAX_ERRCODE) { 242 printf("illegal tftp error %d\n", tftp_error); 243 errno = EIO; 244 } else { 245 #ifdef TFTP_DEBUG 246 printf("tftp-error %d\n", tftp_error); 247 #endif 248 errno = tftperrors[tftp_error]; 249 } 250 free(ptr); 251 /* If we got a NAK return 0, it's usually a directory */ 252 if (tftp_error == 0) 253 return (0); 254 return (-1); 255 case OACK: { 256 struct udphdr *uh; 257 int tftp_oack_len; 258 259 /* 260 * Unexpected OACK. TFTP transfer already in progress. 261 * Drop the pkt. 262 */ 263 if (d->xid != 1) { 264 free(ptr); 265 return (-1); 266 } 267 268 /* 269 * Remember which port this OACK came from, because we need 270 * to send the ACK or errors back to it. 271 */ 272 uh = (struct udphdr *)t - 1; 273 d->destport = uh->uh_sport; 274 275 /* Parse options ACK-ed by the server. */ 276 tftp_oack_len = len - sizeof(t->th_opcode); 277 if (tftp_parse_oack(h, t->th_u.tu_stuff, tftp_oack_len) != 0) { 278 tftp_senderr(h, EOPTNEG, "Malformed OACK"); 279 errno = EIO; 280 free(ptr); 281 return (-1); 282 } 283 *pkt = ptr; 284 *payload = t; 285 return (0); 286 } 287 default: 288 #ifdef TFTP_DEBUG 289 printf("tftp type %d not handled\n", ntohs(t->th_opcode)); 290 #endif 291 free(ptr); 292 return (-1); 293 } 294 } 295 296 /* send request, expect first block (or error) */ 297 static int 298 tftp_makereq(struct tftp_handle *h) 299 { 300 struct { 301 u_char header[HEADER_SIZE]; 302 struct tftphdr t; 303 u_char space[FNAME_SIZE + 6]; 304 } __packed __aligned(4) wbuf; 305 struct tftprecv_extra recv_extra; 306 char *wtail; 307 int l; 308 ssize_t res; 309 void *pkt; 310 struct tftphdr *t; 311 char *tftp_blksize = NULL; 312 int blksize_l; 313 314 /* 315 * Allow overriding default TFTP block size by setting 316 * a tftp.blksize environment variable. 317 */ 318 if ((tftp_blksize = getenv("tftp.blksize")) != NULL) { 319 tftp_set_blksize(h, tftp_blksize); 320 } 321 322 wbuf.t.th_opcode = htons((u_short)RRQ); 323 wtail = wbuf.t.th_stuff; 324 l = strlen(h->path); 325 #ifdef TFTP_PREPEND_PATH 326 if (l > FNAME_SIZE - (sizeof(TFTP_PREPEND_PATH) - 1)) 327 return (ENAMETOOLONG); 328 bcopy(TFTP_PREPEND_PATH, wtail, sizeof(TFTP_PREPEND_PATH) - 1); 329 wtail += sizeof(TFTP_PREPEND_PATH) - 1; 330 #else 331 if (l > FNAME_SIZE) 332 return (ENAMETOOLONG); 333 #endif 334 bcopy(h->path, wtail, l + 1); 335 wtail += l + 1; 336 bcopy("octet", wtail, 6); 337 wtail += 6; 338 bcopy("blksize", wtail, 8); 339 wtail += 8; 340 blksize_l = sprintf(wtail, "%d", h->tftp_blksize); 341 wtail += blksize_l + 1; 342 bcopy("tsize", wtail, 6); 343 wtail += 6; 344 bcopy("0", wtail, 2); 345 wtail += 2; 346 347 h->iodesc->myport = htons(tftpport + (getsecs() & 0x3ff)); 348 h->iodesc->destport = htons(IPPORT_TFTP); 349 h->iodesc->xid = 1; /* expected block */ 350 351 h->currblock = 0; 352 h->islastblock = 0; 353 h->validsize = 0; 354 355 pkt = NULL; 356 recv_extra.tftp_handle = h; 357 res = sendrecv(h->iodesc, &sendudp, &wbuf.t, wtail - (char *)&wbuf.t, 358 &recvtftp, &pkt, (void **)&t, &recv_extra); 359 if (res == -1) { 360 free(pkt); 361 return (errno); 362 } 363 364 free(h->pkt); 365 h->pkt = pkt; 366 h->tftp_hdr = t; 367 368 if (recv_extra.rtype == OACK) 369 return (tftp_getnextblock(h)); 370 371 /* Server ignored our blksize request, revert to TFTP default. */ 372 h->tftp_blksize = SEGSIZE; 373 374 switch (recv_extra.rtype) { 375 case DATA: { 376 h->currblock = 1; 377 h->validsize = res; 378 h->islastblock = 0; 379 if (res < h->tftp_blksize) { 380 h->islastblock = 1; /* very short file */ 381 tftp_sendack(h, h->currblock); 382 h->lastacksent = true; 383 } 384 return (0); 385 } 386 case ERROR: 387 default: 388 return (errno); 389 } 390 391 } 392 393 /* ack block, expect next */ 394 static int 395 tftp_getnextblock(struct tftp_handle *h) 396 { 397 struct { 398 u_char header[HEADER_SIZE]; 399 struct tftphdr t; 400 } __packed __aligned(4) wbuf; 401 struct tftprecv_extra recv_extra; 402 char *wtail; 403 int res; 404 void *pkt; 405 struct tftphdr *t; 406 407 wbuf.t.th_opcode = htons((u_short)ACK); 408 wtail = (char *)&wbuf.t.th_block; 409 wbuf.t.th_block = htons((u_short)h->currblock); 410 wtail += 2; 411 412 h->iodesc->xid = h->currblock + 1; /* expected block */ 413 414 pkt = NULL; 415 recv_extra.tftp_handle = h; 416 res = sendrecv(h->iodesc, &sendudp, &wbuf.t, wtail - (char *)&wbuf.t, 417 &recvtftp, &pkt, (void **)&t, &recv_extra); 418 419 if (res == -1) { /* 0 is OK! */ 420 free(pkt); 421 return (errno); 422 } 423 424 free(h->pkt); 425 h->pkt = pkt; 426 h->tftp_hdr = t; 427 h->currblock++; 428 h->validsize = res; 429 if (res < h->tftp_blksize) 430 h->islastblock = 1; /* EOF */ 431 432 if (h->islastblock == 1) { 433 /* Send an ACK for the last block */ 434 wbuf.t.th_block = htons((u_short)h->currblock); 435 sendudp(h->iodesc, &wbuf.t, wtail - (char *)&wbuf.t); 436 } 437 438 return (0); 439 } 440 441 static int 442 tftp_open(const char *path, struct open_file *f) 443 { 444 struct devdesc *dev; 445 struct tftp_handle *tftpfile; 446 struct iodesc *io; 447 int res; 448 size_t pathsize; 449 const char *extraslash; 450 451 if (netproto != NET_TFTP) 452 return (EINVAL); 453 454 if (f->f_dev->dv_type != DEVT_NET) 455 return (EINVAL); 456 457 if (is_open) 458 return (EBUSY); 459 460 tftpfile = calloc(1, sizeof(*tftpfile)); 461 if (!tftpfile) 462 return (ENOMEM); 463 464 tftpfile->tftp_blksize = TFTP_REQUESTED_BLKSIZE; 465 dev = f->f_devdata; 466 tftpfile->iodesc = io = socktodesc(*(int *)(dev->d_opendata)); 467 if (io == NULL) { 468 free(tftpfile); 469 return (EINVAL); 470 } 471 472 io->destip = rootip; 473 tftpfile->off = 0; 474 pathsize = (strlen(rootpath) + 1 + strlen(path) + 1) * sizeof(char); 475 tftpfile->path = malloc(pathsize); 476 if (tftpfile->path == NULL) { 477 free(tftpfile); 478 return (ENOMEM); 479 } 480 if (rootpath[strlen(rootpath) - 1] == '/' || path[0] == '/') 481 extraslash = ""; 482 else 483 extraslash = "/"; 484 res = snprintf(tftpfile->path, pathsize, "%s%s%s", 485 rootpath, extraslash, path); 486 if (res < 0 || res > pathsize) { 487 free(tftpfile->path); 488 free(tftpfile); 489 return (ENOMEM); 490 } 491 492 res = tftp_makereq(tftpfile); 493 494 if (res) { 495 free(tftpfile->path); 496 free(tftpfile->pkt); 497 free(tftpfile); 498 return (res); 499 } 500 f->f_fsdata = tftpfile; 501 is_open = 1; 502 return (0); 503 } 504 505 static int 506 tftp_read(struct open_file *f, void *addr, size_t size, 507 size_t *resid /* out */) 508 { 509 struct tftp_handle *tftpfile; 510 size_t res; 511 int rc; 512 513 rc = 0; 514 res = size; 515 tftpfile = f->f_fsdata; 516 517 /* Make sure we will not read past file end */ 518 if (tftpfile->tftp_tsize > 0 && 519 tftpfile->off + size > tftpfile->tftp_tsize) { 520 size = tftpfile->tftp_tsize - tftpfile->off; 521 } 522 523 if (tftpfile->tftp_cache != NULL) { 524 bcopy(tftpfile->tftp_cache + tftpfile->off, 525 addr, size); 526 527 addr = (char *)addr + size; 528 tftpfile->off += size; 529 res -= size; 530 goto out; 531 } 532 533 while (size > 0) { 534 int needblock, count; 535 536 twiddle(32); 537 538 needblock = tftpfile->off / tftpfile->tftp_blksize + 1; 539 540 if (tftpfile->currblock > needblock) { /* seek backwards */ 541 tftp_senderr(tftpfile, 0, "No error: read aborted"); 542 rc = tftp_makereq(tftpfile); 543 if (rc != 0) 544 break; 545 } 546 547 while (tftpfile->currblock < needblock) { 548 549 rc = tftp_getnextblock(tftpfile); 550 if (rc) { /* no answer */ 551 #ifdef TFTP_DEBUG 552 printf("tftp: read error\n"); 553 #endif 554 if (tftpfile->tries > TFTP_TRIES) { 555 return (rc); 556 } else { 557 tftpfile->tries++; 558 tftp_makereq(tftpfile); 559 } 560 } 561 if (tftpfile->islastblock) 562 break; 563 } 564 565 if (tftpfile->currblock == needblock) { 566 int offinblock, inbuffer; 567 568 offinblock = tftpfile->off % tftpfile->tftp_blksize; 569 570 inbuffer = tftpfile->validsize - offinblock; 571 if (inbuffer < 0) { 572 #ifdef TFTP_DEBUG 573 printf("tftp: invalid offset %d\n", 574 tftpfile->off); 575 #endif 576 return (EINVAL); 577 } 578 count = (size < inbuffer ? size : inbuffer); 579 bcopy(tftpfile->tftp_hdr->th_data + offinblock, 580 addr, count); 581 582 addr = (char *)addr + count; 583 tftpfile->off += count; 584 size -= count; 585 res -= count; 586 587 if ((tftpfile->islastblock) && (count == inbuffer)) 588 break; /* EOF */ 589 } else { 590 #ifdef TFTP_DEBUG 591 printf("tftp: block %d not found\n", needblock); 592 #endif 593 return (EINVAL); 594 } 595 596 } 597 598 out: 599 if (resid != NULL) 600 *resid = res; 601 return (rc); 602 } 603 604 static int 605 tftp_close(struct open_file *f) 606 { 607 struct tftp_handle *tftpfile; 608 tftpfile = f->f_fsdata; 609 610 if (tftpfile->lastacksent == false) 611 tftp_senderr(tftpfile, 0, "No error: file closed"); 612 613 if (tftpfile) { 614 free(tftpfile->path); 615 free(tftpfile->pkt); 616 free(tftpfile->tftp_cache); 617 free(tftpfile); 618 } 619 is_open = 0; 620 return (0); 621 } 622 623 static int 624 tftp_stat(struct open_file *f, struct stat *sb) 625 { 626 struct tftp_handle *tftpfile; 627 tftpfile = f->f_fsdata; 628 629 sb->st_mode = 0444 | S_IFREG; 630 sb->st_nlink = 1; 631 sb->st_uid = 0; 632 sb->st_gid = 0; 633 sb->st_size = tftpfile->tftp_tsize; 634 return (0); 635 } 636 637 static off_t 638 tftp_seek(struct open_file *f, off_t offset, int where) 639 { 640 struct tftp_handle *tftpfile; 641 tftpfile = f->f_fsdata; 642 643 switch (where) { 644 case SEEK_SET: 645 tftpfile->off = offset; 646 break; 647 case SEEK_CUR: 648 tftpfile->off += offset; 649 break; 650 default: 651 errno = EOFFSET; 652 return (-1); 653 } 654 return (tftpfile->off); 655 } 656 657 static int 658 tftp_preload(struct open_file *f) 659 { 660 struct tftp_handle *tftpfile; 661 char *cache; 662 int rc; 663 #ifdef TFTP_DEBUG 664 time_t start, end; 665 #endif 666 667 tftpfile = f->f_fsdata; 668 cache = malloc(sizeof(char) * tftpfile->tftp_tsize); 669 if (cache == NULL) { 670 printf("Couldn't allocate %ju bytes for preload caching" 671 ", disabling caching\n", 672 (uintmax_t)sizeof(char) * tftpfile->tftp_tsize); 673 return (-1); 674 } 675 676 #ifdef TFTP_DEBUG 677 start = getsecs(); 678 printf("Preloading %s ", tftpfile->path); 679 #endif 680 if (tftpfile->currblock == 1) 681 bcopy(tftpfile->tftp_hdr->th_data, 682 cache, 683 tftpfile->validsize); 684 else 685 tftpfile->currblock = 0; 686 687 while (tftpfile->islastblock == 0) { 688 twiddle(32); 689 rc = tftp_getnextblock(tftpfile); 690 if (rc) { 691 free(cache); 692 printf("Got TFTP error %d, disabling caching\n", rc); 693 return (rc); 694 } 695 bcopy(tftpfile->tftp_hdr->th_data, 696 cache + (tftpfile->tftp_blksize * (tftpfile->currblock - 1)), 697 tftpfile->validsize); 698 } 699 #ifdef TFTP_DEBUG 700 end = getsecs(); 701 printf("\nPreloaded %s (%ju bytes) during %jd seconds\n", 702 tftpfile->path, (intmax_t)tftpfile->tftp_tsize, 703 (intmax_t)end - start); 704 #endif 705 706 tftpfile->tftp_cache = cache; 707 return (0); 708 } 709 710 static int 711 tftp_set_blksize(struct tftp_handle *h, const char *str) 712 { 713 char *endptr; 714 int new_blksize; 715 int ret = 0; 716 717 if (h == NULL || str == NULL) 718 return (ret); 719 720 new_blksize = 721 (unsigned int)strtol(str, &endptr, 0); 722 723 /* 724 * Only accept blksize value if it is numeric. 725 * RFC2348 specifies that acceptable values are 8-65464. 726 * Let's choose a limit less than MAXRSPACE. 727 */ 728 if (*endptr == '\0' && new_blksize >= 8 && 729 new_blksize <= TFTP_MAX_BLKSIZE) { 730 h->tftp_blksize = new_blksize; 731 ret = 1; 732 } 733 734 return (ret); 735 } 736 737 /* 738 * In RFC2347, the TFTP Option Acknowledgement package (OACK) 739 * is used to acknowledge a client's option negotiation request. 740 * The format of an OACK packet is: 741 * +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+ 742 * | opc | opt1 | 0 | value1 | 0 | optN | 0 | valueN | 0 | 743 * +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+ 744 * 745 * opc 746 * The opcode field contains a 6, for Option Acknowledgment. 747 * 748 * opt1 749 * The first option acknowledgment, copied from the original 750 * request. 751 * 752 * value1 753 * The acknowledged value associated with the first option. If 754 * and how this value may differ from the original request is 755 * detailed in the specification for the option. 756 * 757 * optN, valueN 758 * The final option/value acknowledgment pair. 759 */ 760 static int 761 tftp_parse_oack(struct tftp_handle *h, char *buf, size_t len) 762 { 763 /* 764 * We parse the OACK strings into an array 765 * of name-value pairs. 766 */ 767 char *tftp_options[128] = { 0 }; 768 char *val = buf; 769 int i = 0; 770 int option_idx = 0; 771 int blksize_is_set = 0; 772 int tsize = 0; 773 774 unsigned int orig_blksize; 775 776 while (option_idx < 128 && i < len) { 777 if (buf[i] == '\0') { 778 if (&buf[i] > val) { 779 tftp_options[option_idx] = val; 780 val = &buf[i] + 1; 781 ++option_idx; 782 } 783 } 784 ++i; 785 } 786 787 /* Save the block size we requested for sanity check later. */ 788 orig_blksize = h->tftp_blksize; 789 790 /* 791 * Parse individual TFTP options. 792 * * "blksize" is specified in RFC2348. 793 * * "tsize" is specified in RFC2349. 794 */ 795 for (i = 0; i < option_idx; i += 2) { 796 if (strcasecmp(tftp_options[i], "blksize") == 0) { 797 if (i + 1 < option_idx) 798 blksize_is_set = 799 tftp_set_blksize(h, tftp_options[i + 1]); 800 } else if (strcasecmp(tftp_options[i], "tsize") == 0) { 801 if (i + 1 < option_idx) 802 tsize = strtol(tftp_options[i + 1], NULL, 10); 803 if (tsize != 0) 804 h->tftp_tsize = tsize; 805 } else { 806 /* 807 * Do not allow any options we did not expect to be 808 * ACKed. 809 */ 810 printf("unexpected tftp option '%s'\n", 811 tftp_options[i]); 812 return (-1); 813 } 814 } 815 816 if (!blksize_is_set) { 817 /* 818 * If TFTP blksize was not set, try defaulting 819 * to the legacy TFTP blksize of SEGSIZE(512) 820 */ 821 h->tftp_blksize = SEGSIZE; 822 } else if (h->tftp_blksize > orig_blksize) { 823 /* 824 * Server should not be proposing block sizes that 825 * exceed what we said we can handle. 826 */ 827 printf("unexpected blksize %u\n", h->tftp_blksize); 828 return (-1); 829 } 830 831 #ifdef TFTP_DEBUG 832 printf("tftp_blksize: %u\n", h->tftp_blksize); 833 printf("tftp_tsize: %lu\n", h->tftp_tsize); 834 #endif 835 return (0); 836 } 837