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 __FBSDID("$FreeBSD$"); 36 37 /* 38 * Simple TFTP implementation for libsa. 39 * Assumes: 40 * - socket descriptor (int) at dev->d_opendata, dev stored at 41 * open_file->f_devdata 42 * - server host IP in global rootip 43 * Restrictions: 44 * - read only 45 * - lseek only with SEEK_SET or SEEK_CUR 46 * - no big time differences between transfers (<tftp timeout) 47 */ 48 49 #include <sys/types.h> 50 #include <sys/stat.h> 51 #include <netinet/in.h> 52 #include <netinet/udp.h> 53 #include <netinet/in_systm.h> 54 #include <arpa/tftp.h> 55 56 #include <string.h> 57 58 #include "stand.h" 59 #include "net.h" 60 #include "netif.h" 61 62 #include "tftp.h" 63 64 struct tftp_handle; 65 struct tftprecv_extra; 66 67 static ssize_t recvtftp(struct iodesc *, void **, void **, time_t, void *); 68 static int tftp_open(const char *, struct open_file *); 69 static int tftp_close(struct open_file *); 70 static int tftp_parse_oack(struct tftp_handle *, char *, size_t); 71 static int tftp_read(struct open_file *, void *, size_t, size_t *); 72 static off_t tftp_seek(struct open_file *, off_t, int); 73 static int tftp_set_blksize(struct tftp_handle *, const char *); 74 static int tftp_stat(struct open_file *, struct stat *); 75 static int tftp_preload(struct open_file *); 76 77 struct fs_ops tftp_fsops = { 78 .fs_name = "tftp", 79 .fo_open = tftp_open, 80 .fo_close = tftp_close, 81 .fo_read = tftp_read, 82 .fo_write = null_write, 83 .fo_seek = tftp_seek, 84 .fo_stat = tftp_stat, 85 .fo_preload = tftp_preload, 86 .fo_readdir = null_readdir 87 }; 88 89 static int tftpport = 2000; 90 static int is_open = 0; 91 92 /* 93 * The legacy TFTP_BLKSIZE value was SEGSIZE(512). 94 * TFTP_REQUESTED_BLKSIZE of 1428 is (Ethernet MTU, less the TFTP, UDP and 95 * IP header lengths). 96 */ 97 #define TFTP_REQUESTED_BLKSIZE 1428 98 99 /* 100 * Choose a blksize big enough so we can test with Ethernet 101 * Jumbo frames in the future. 102 */ 103 #define TFTP_MAX_BLKSIZE 9008 104 #define TFTP_TRIES 2 105 106 struct tftp_handle { 107 struct iodesc *iodesc; 108 int currblock; /* contents of lastdata */ 109 unsigned int islastblock:1; /* flag */ 110 unsigned int tries:4; /* number of read attempts */ 111 int validsize; 112 int off; 113 char *path; /* saved for re-requests */ 114 unsigned int tftp_blksize; 115 unsigned long tftp_tsize; 116 void *pkt; 117 struct tftphdr *tftp_hdr; 118 char *tftp_cache; 119 bool lastacksent; 120 }; 121 122 struct tftprecv_extra { 123 struct tftp_handle *tftp_handle; 124 unsigned short rtype; /* Received type */ 125 }; 126 127 #define TFTP_MAX_ERRCODE EOPTNEG 128 static const int tftperrors[TFTP_MAX_ERRCODE + 1] = { 129 0, /* NAK */ 130 ENOENT, 131 EPERM, 132 ENOSPC, 133 EINVAL, /* ??? */ 134 EINVAL, /* ??? */ 135 EEXIST, 136 EINVAL, /* ??? */ 137 EINVAL, /* Option negotiation failed. */ 138 }; 139 140 static int tftp_getnextblock(struct tftp_handle *h); 141 142 /* send error message back. */ 143 static void 144 tftp_senderr(struct tftp_handle *h, u_short errcode, const char *msg) 145 { 146 struct { 147 u_char header[HEADER_SIZE]; 148 struct tftphdr t; 149 u_char space[63]; /* +1 from t */ 150 } __packed __aligned(4) wbuf; 151 char *wtail; 152 int len; 153 154 len = strlen(msg); 155 if (len > sizeof(wbuf.space)) 156 len = sizeof(wbuf.space); 157 158 wbuf.t.th_opcode = htons((u_short)ERROR); 159 wbuf.t.th_code = htons(errcode); 160 161 wtail = wbuf.t.th_msg; 162 bcopy(msg, wtail, len); 163 wtail[len] = '\0'; 164 wtail += len + 1; 165 166 sendudp(h->iodesc, &wbuf.t, wtail - (char *)&wbuf.t); 167 } 168 169 static void 170 tftp_sendack(struct tftp_handle *h, u_short block) 171 { 172 struct { 173 u_char header[HEADER_SIZE]; 174 struct tftphdr t; 175 } __packed __aligned(4) wbuf; 176 char *wtail; 177 178 wbuf.t.th_opcode = htons((u_short)ACK); 179 wtail = (char *)&wbuf.t.th_block; 180 wbuf.t.th_block = htons(block); 181 wtail += 2; 182 183 sendudp(h->iodesc, &wbuf.t, wtail - (char *)&wbuf.t); 184 } 185 186 static ssize_t 187 recvtftp(struct iodesc *d, void **pkt, void **payload, time_t tleft, 188 void *recv_extra) 189 { 190 struct tftprecv_extra *extra; 191 struct tftp_handle *h; 192 struct tftphdr *t; 193 void *ptr = NULL; 194 ssize_t len; 195 int tftp_error; 196 197 errno = 0; 198 extra = recv_extra; 199 h = extra->tftp_handle; 200 201 len = readudp(d, &ptr, (void **)&t, tleft); 202 203 if (len < 4) { 204 free(ptr); 205 return (-1); 206 } 207 208 extra->rtype = ntohs(t->th_opcode); 209 switch (ntohs(t->th_opcode)) { 210 case DATA: { 211 int got; 212 213 if (htons(t->th_block) < (u_short)d->xid) { 214 /* 215 * Apparently our ACK was missed, re-send. 216 */ 217 tftp_sendack(h, htons(t->th_block)); 218 free(ptr); 219 return (-1); 220 } 221 if (htons(t->th_block) != (u_short)d->xid) { 222 /* 223 * Packet from the future, drop this. 224 */ 225 free(ptr); 226 return (-1); 227 } 228 if (d->xid == 1) { 229 /* 230 * First data packet from new port. 231 */ 232 struct udphdr *uh; 233 uh = (struct udphdr *)t - 1; 234 d->destport = uh->uh_sport; 235 } 236 got = len - (t->th_data - (char *)t); 237 *pkt = ptr; 238 *payload = t; 239 return (got); 240 } 241 case ERROR: 242 tftp_error = ntohs(t->th_code); 243 if ((unsigned)tftp_error > TFTP_MAX_ERRCODE) { 244 printf("illegal tftp error %d\n", tftp_error); 245 errno = EIO; 246 } else { 247 #ifdef TFTP_DEBUG 248 printf("tftp-error %d\n", tftp_error); 249 #endif 250 errno = tftperrors[tftp_error]; 251 } 252 free(ptr); 253 /* If we got a NAK return 0, it's usually a directory */ 254 if (tftp_error == 0) 255 return (0); 256 return (-1); 257 case OACK: { 258 struct udphdr *uh; 259 int tftp_oack_len; 260 261 /* 262 * Unexpected OACK. TFTP transfer already in progress. 263 * Drop the pkt. 264 */ 265 if (d->xid != 1) { 266 free(ptr); 267 return (-1); 268 } 269 270 /* 271 * Remember which port this OACK came from, because we need 272 * to send the ACK or errors back to it. 273 */ 274 uh = (struct udphdr *)t - 1; 275 d->destport = uh->uh_sport; 276 277 /* Parse options ACK-ed by the server. */ 278 tftp_oack_len = len - sizeof(t->th_opcode); 279 if (tftp_parse_oack(h, t->th_u.tu_stuff, tftp_oack_len) != 0) { 280 tftp_senderr(h, EOPTNEG, "Malformed OACK"); 281 errno = EIO; 282 free(ptr); 283 return (-1); 284 } 285 *pkt = ptr; 286 *payload = t; 287 return (0); 288 } 289 default: 290 #ifdef TFTP_DEBUG 291 printf("tftp type %d not handled\n", ntohs(t->th_opcode)); 292 #endif 293 free(ptr); 294 return (-1); 295 } 296 } 297 298 /* send request, expect first block (or error) */ 299 static int 300 tftp_makereq(struct tftp_handle *h) 301 { 302 struct { 303 u_char header[HEADER_SIZE]; 304 struct tftphdr t; 305 u_char space[FNAME_SIZE + 6]; 306 } __packed __aligned(4) wbuf; 307 struct tftprecv_extra recv_extra; 308 char *wtail; 309 int l; 310 ssize_t res; 311 void *pkt; 312 struct tftphdr *t; 313 char *tftp_blksize = NULL; 314 int blksize_l; 315 316 /* 317 * Allow overriding default TFTP block size by setting 318 * a tftp.blksize environment variable. 319 */ 320 if ((tftp_blksize = getenv("tftp.blksize")) != NULL) { 321 tftp_set_blksize(h, tftp_blksize); 322 } 323 324 wbuf.t.th_opcode = htons((u_short)RRQ); 325 wtail = wbuf.t.th_stuff; 326 l = strlen(h->path); 327 #ifdef TFTP_PREPEND_PATH 328 if (l > FNAME_SIZE - (sizeof(TFTP_PREPEND_PATH) - 1)) 329 return (ENAMETOOLONG); 330 bcopy(TFTP_PREPEND_PATH, wtail, sizeof(TFTP_PREPEND_PATH) - 1); 331 wtail += sizeof(TFTP_PREPEND_PATH) - 1; 332 #else 333 if (l > FNAME_SIZE) 334 return (ENAMETOOLONG); 335 #endif 336 bcopy(h->path, wtail, l + 1); 337 wtail += l + 1; 338 bcopy("octet", wtail, 6); 339 wtail += 6; 340 bcopy("blksize", wtail, 8); 341 wtail += 8; 342 blksize_l = sprintf(wtail, "%d", h->tftp_blksize); 343 wtail += blksize_l + 1; 344 bcopy("tsize", wtail, 6); 345 wtail += 6; 346 bcopy("0", wtail, 2); 347 wtail += 2; 348 349 h->iodesc->myport = htons(tftpport + (getsecs() & 0x3ff)); 350 h->iodesc->destport = htons(IPPORT_TFTP); 351 h->iodesc->xid = 1; /* expected block */ 352 353 h->currblock = 0; 354 h->islastblock = 0; 355 h->validsize = 0; 356 357 pkt = NULL; 358 recv_extra.tftp_handle = h; 359 res = sendrecv(h->iodesc, &sendudp, &wbuf.t, wtail - (char *)&wbuf.t, 360 &recvtftp, &pkt, (void **)&t, &recv_extra); 361 if (res == -1) { 362 free(pkt); 363 return (errno); 364 } 365 366 free(h->pkt); 367 h->pkt = pkt; 368 h->tftp_hdr = t; 369 370 if (recv_extra.rtype == OACK) 371 return (tftp_getnextblock(h)); 372 373 /* Server ignored our blksize request, revert to TFTP default. */ 374 h->tftp_blksize = SEGSIZE; 375 376 switch (recv_extra.rtype) { 377 case DATA: { 378 h->currblock = 1; 379 h->validsize = res; 380 h->islastblock = 0; 381 if (res < h->tftp_blksize) { 382 h->islastblock = 1; /* very short file */ 383 tftp_sendack(h, h->currblock); 384 h->lastacksent = true; 385 } 386 return (0); 387 } 388 case ERROR: 389 default: 390 return (errno); 391 } 392 393 } 394 395 /* ack block, expect next */ 396 static int 397 tftp_getnextblock(struct tftp_handle *h) 398 { 399 struct { 400 u_char header[HEADER_SIZE]; 401 struct tftphdr t; 402 } __packed __aligned(4) wbuf; 403 struct tftprecv_extra recv_extra; 404 char *wtail; 405 int res; 406 void *pkt; 407 struct tftphdr *t; 408 409 wbuf.t.th_opcode = htons((u_short)ACK); 410 wtail = (char *)&wbuf.t.th_block; 411 wbuf.t.th_block = htons((u_short)h->currblock); 412 wtail += 2; 413 414 h->iodesc->xid = h->currblock + 1; /* expected block */ 415 416 pkt = NULL; 417 recv_extra.tftp_handle = h; 418 res = sendrecv(h->iodesc, &sendudp, &wbuf.t, wtail - (char *)&wbuf.t, 419 &recvtftp, &pkt, (void **)&t, &recv_extra); 420 421 if (res == -1) { /* 0 is OK! */ 422 free(pkt); 423 return (errno); 424 } 425 426 free(h->pkt); 427 h->pkt = pkt; 428 h->tftp_hdr = t; 429 h->currblock++; 430 h->validsize = res; 431 if (res < h->tftp_blksize) 432 h->islastblock = 1; /* EOF */ 433 434 if (h->islastblock == 1) { 435 /* Send an ACK for the last block */ 436 wbuf.t.th_block = htons((u_short)h->currblock); 437 sendudp(h->iodesc, &wbuf.t, wtail - (char *)&wbuf.t); 438 } 439 440 return (0); 441 } 442 443 static int 444 tftp_open(const char *path, struct open_file *f) 445 { 446 struct devdesc *dev; 447 struct tftp_handle *tftpfile; 448 struct iodesc *io; 449 int res; 450 size_t pathsize; 451 const char *extraslash; 452 453 if (netproto != NET_TFTP) 454 return (EINVAL); 455 456 if (f->f_dev->dv_type != DEVT_NET) 457 return (EINVAL); 458 459 if (is_open) 460 return (EBUSY); 461 462 tftpfile = calloc(1, sizeof(*tftpfile)); 463 if (!tftpfile) 464 return (ENOMEM); 465 466 tftpfile->tftp_blksize = TFTP_REQUESTED_BLKSIZE; 467 dev = f->f_devdata; 468 tftpfile->iodesc = io = socktodesc(*(int *)(dev->d_opendata)); 469 if (io == NULL) { 470 free(tftpfile); 471 return (EINVAL); 472 } 473 474 io->destip = rootip; 475 tftpfile->off = 0; 476 pathsize = (strlen(rootpath) + 1 + strlen(path) + 1) * sizeof(char); 477 tftpfile->path = malloc(pathsize); 478 if (tftpfile->path == NULL) { 479 free(tftpfile); 480 return (ENOMEM); 481 } 482 if (rootpath[strlen(rootpath) - 1] == '/' || path[0] == '/') 483 extraslash = ""; 484 else 485 extraslash = "/"; 486 res = snprintf(tftpfile->path, pathsize, "%s%s%s", 487 rootpath, extraslash, path); 488 if (res < 0 || res > pathsize) { 489 free(tftpfile->path); 490 free(tftpfile); 491 return (ENOMEM); 492 } 493 494 res = tftp_makereq(tftpfile); 495 496 if (res) { 497 free(tftpfile->path); 498 free(tftpfile->pkt); 499 free(tftpfile); 500 return (res); 501 } 502 f->f_fsdata = tftpfile; 503 is_open = 1; 504 return (0); 505 } 506 507 static int 508 tftp_read(struct open_file *f, void *addr, size_t size, 509 size_t *resid /* out */) 510 { 511 struct tftp_handle *tftpfile; 512 size_t res; 513 int rc; 514 515 rc = 0; 516 res = size; 517 tftpfile = f->f_fsdata; 518 519 /* Make sure we will not read past file end */ 520 if (tftpfile->tftp_tsize > 0 && 521 tftpfile->off + size > tftpfile->tftp_tsize) { 522 size = tftpfile->tftp_tsize - tftpfile->off; 523 } 524 525 if (tftpfile->tftp_cache != NULL) { 526 bcopy(tftpfile->tftp_cache + tftpfile->off, 527 addr, size); 528 529 addr = (char *)addr + size; 530 tftpfile->off += size; 531 res -= size; 532 goto out; 533 } 534 535 while (size > 0) { 536 int needblock, count; 537 538 twiddle(32); 539 540 needblock = tftpfile->off / tftpfile->tftp_blksize + 1; 541 542 if (tftpfile->currblock > needblock) { /* seek backwards */ 543 tftp_senderr(tftpfile, 0, "No error: read aborted"); 544 rc = tftp_makereq(tftpfile); 545 if (rc != 0) 546 break; 547 } 548 549 while (tftpfile->currblock < needblock) { 550 551 rc = tftp_getnextblock(tftpfile); 552 if (rc) { /* no answer */ 553 #ifdef TFTP_DEBUG 554 printf("tftp: read error\n"); 555 #endif 556 if (tftpfile->tries > TFTP_TRIES) { 557 return (rc); 558 } else { 559 tftpfile->tries++; 560 tftp_makereq(tftpfile); 561 } 562 } 563 if (tftpfile->islastblock) 564 break; 565 } 566 567 if (tftpfile->currblock == needblock) { 568 int offinblock, inbuffer; 569 570 offinblock = tftpfile->off % tftpfile->tftp_blksize; 571 572 inbuffer = tftpfile->validsize - offinblock; 573 if (inbuffer < 0) { 574 #ifdef TFTP_DEBUG 575 printf("tftp: invalid offset %d\n", 576 tftpfile->off); 577 #endif 578 return (EINVAL); 579 } 580 count = (size < inbuffer ? size : inbuffer); 581 bcopy(tftpfile->tftp_hdr->th_data + offinblock, 582 addr, count); 583 584 addr = (char *)addr + count; 585 tftpfile->off += count; 586 size -= count; 587 res -= count; 588 589 if ((tftpfile->islastblock) && (count == inbuffer)) 590 break; /* EOF */ 591 } else { 592 #ifdef TFTP_DEBUG 593 printf("tftp: block %d not found\n", needblock); 594 #endif 595 return (EINVAL); 596 } 597 598 } 599 600 out: 601 if (resid != NULL) 602 *resid = res; 603 return (rc); 604 } 605 606 static int 607 tftp_close(struct open_file *f) 608 { 609 struct tftp_handle *tftpfile; 610 tftpfile = f->f_fsdata; 611 612 if (tftpfile->lastacksent == false) 613 tftp_senderr(tftpfile, 0, "No error: file closed"); 614 615 if (tftpfile) { 616 free(tftpfile->path); 617 free(tftpfile->pkt); 618 free(tftpfile->tftp_cache); 619 free(tftpfile); 620 } 621 is_open = 0; 622 return (0); 623 } 624 625 static int 626 tftp_stat(struct open_file *f, struct stat *sb) 627 { 628 struct tftp_handle *tftpfile; 629 tftpfile = f->f_fsdata; 630 631 sb->st_mode = 0444 | S_IFREG; 632 sb->st_nlink = 1; 633 sb->st_uid = 0; 634 sb->st_gid = 0; 635 sb->st_size = tftpfile->tftp_tsize; 636 return (0); 637 } 638 639 static off_t 640 tftp_seek(struct open_file *f, off_t offset, int where) 641 { 642 struct tftp_handle *tftpfile; 643 tftpfile = f->f_fsdata; 644 645 switch (where) { 646 case SEEK_SET: 647 tftpfile->off = offset; 648 break; 649 case SEEK_CUR: 650 tftpfile->off += offset; 651 break; 652 default: 653 errno = EOFFSET; 654 return (-1); 655 } 656 return (tftpfile->off); 657 } 658 659 static int 660 tftp_preload(struct open_file *f) 661 { 662 struct tftp_handle *tftpfile; 663 char *cache; 664 int rc; 665 #ifdef TFTP_DEBUG 666 time_t start, end; 667 #endif 668 669 tftpfile = f->f_fsdata; 670 cache = malloc(sizeof(char) * tftpfile->tftp_tsize); 671 if (cache == NULL) { 672 printf("Couldn't allocate %ju bytes for preload caching" 673 ", disabling caching\n", 674 (uintmax_t)sizeof(char) * tftpfile->tftp_tsize); 675 return (-1); 676 } 677 678 #ifdef TFTP_DEBUG 679 start = getsecs(); 680 printf("Preloading %s ", tftpfile->path); 681 #endif 682 if (tftpfile->currblock == 1) 683 bcopy(tftpfile->tftp_hdr->th_data, 684 cache, 685 tftpfile->validsize); 686 else 687 tftpfile->currblock = 0; 688 689 while (tftpfile->islastblock == 0) { 690 twiddle(32); 691 rc = tftp_getnextblock(tftpfile); 692 if (rc) { 693 free(cache); 694 printf("Got TFTP error %d, disabling caching\n", rc); 695 return (rc); 696 } 697 bcopy(tftpfile->tftp_hdr->th_data, 698 cache + (tftpfile->tftp_blksize * (tftpfile->currblock - 1)), 699 tftpfile->validsize); 700 } 701 #ifdef TFTP_DEBUG 702 end = getsecs(); 703 printf("\nPreloaded %s (%ju bytes) during %jd seconds\n", 704 tftpfile->path, (intmax_t)tftpfile->tftp_tsize, 705 (intmax_t)end - start); 706 #endif 707 708 tftpfile->tftp_cache = cache; 709 return (0); 710 } 711 712 static int 713 tftp_set_blksize(struct tftp_handle *h, const char *str) 714 { 715 char *endptr; 716 int new_blksize; 717 int ret = 0; 718 719 if (h == NULL || str == NULL) 720 return (ret); 721 722 new_blksize = 723 (unsigned int)strtol(str, &endptr, 0); 724 725 /* 726 * Only accept blksize value if it is numeric. 727 * RFC2348 specifies that acceptable values are 8-65464. 728 * Let's choose a limit less than MAXRSPACE. 729 */ 730 if (*endptr == '\0' && new_blksize >= 8 && 731 new_blksize <= TFTP_MAX_BLKSIZE) { 732 h->tftp_blksize = new_blksize; 733 ret = 1; 734 } 735 736 return (ret); 737 } 738 739 /* 740 * In RFC2347, the TFTP Option Acknowledgement package (OACK) 741 * is used to acknowledge a client's option negotiation request. 742 * The format of an OACK packet is: 743 * +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+ 744 * | opc | opt1 | 0 | value1 | 0 | optN | 0 | valueN | 0 | 745 * +-------+---~~---+---+---~~---+---+---~~---+---+---~~---+---+ 746 * 747 * opc 748 * The opcode field contains a 6, for Option Acknowledgment. 749 * 750 * opt1 751 * The first option acknowledgment, copied from the original 752 * request. 753 * 754 * value1 755 * The acknowledged value associated with the first option. If 756 * and how this value may differ from the original request is 757 * detailed in the specification for the option. 758 * 759 * optN, valueN 760 * The final option/value acknowledgment pair. 761 */ 762 static int 763 tftp_parse_oack(struct tftp_handle *h, char *buf, size_t len) 764 { 765 /* 766 * We parse the OACK strings into an array 767 * of name-value pairs. 768 */ 769 char *tftp_options[128] = { 0 }; 770 char *val = buf; 771 int i = 0; 772 int option_idx = 0; 773 int blksize_is_set = 0; 774 int tsize = 0; 775 776 unsigned int orig_blksize; 777 778 while (option_idx < 128 && i < len) { 779 if (buf[i] == '\0') { 780 if (&buf[i] > val) { 781 tftp_options[option_idx] = val; 782 val = &buf[i] + 1; 783 ++option_idx; 784 } 785 } 786 ++i; 787 } 788 789 /* Save the block size we requested for sanity check later. */ 790 orig_blksize = h->tftp_blksize; 791 792 /* 793 * Parse individual TFTP options. 794 * * "blksize" is specified in RFC2348. 795 * * "tsize" is specified in RFC2349. 796 */ 797 for (i = 0; i < option_idx; i += 2) { 798 if (strcasecmp(tftp_options[i], "blksize") == 0) { 799 if (i + 1 < option_idx) 800 blksize_is_set = 801 tftp_set_blksize(h, tftp_options[i + 1]); 802 } else if (strcasecmp(tftp_options[i], "tsize") == 0) { 803 if (i + 1 < option_idx) 804 tsize = strtol(tftp_options[i + 1], NULL, 10); 805 if (tsize != 0) 806 h->tftp_tsize = tsize; 807 } else { 808 /* 809 * Do not allow any options we did not expect to be 810 * ACKed. 811 */ 812 printf("unexpected tftp option '%s'\n", 813 tftp_options[i]); 814 return (-1); 815 } 816 } 817 818 if (!blksize_is_set) { 819 /* 820 * If TFTP blksize was not set, try defaulting 821 * to the legacy TFTP blksize of SEGSIZE(512) 822 */ 823 h->tftp_blksize = SEGSIZE; 824 } else if (h->tftp_blksize > orig_blksize) { 825 /* 826 * Server should not be proposing block sizes that 827 * exceed what we said we can handle. 828 */ 829 printf("unexpected blksize %u\n", h->tftp_blksize); 830 return (-1); 831 } 832 833 #ifdef TFTP_DEBUG 834 printf("tftp_blksize: %u\n", h->tftp_blksize); 835 printf("tftp_tsize: %lu\n", h->tftp_tsize); 836 #endif 837 return (0); 838 } 839