1 /* 2 * Copyright (c) 1983, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by the University of 16 * California, Berkeley and its contributors. 17 * 4. Neither the name of the University nor the names of its contributors 18 * may be used to endorse or promote products derived from this software 19 * without specific prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * @(#) Copyright (c) 1983, 1993 The Regents of the University of California. All rights reserved. 34 * @(#)tftpd.c 8.1 (Berkeley) 6/4/93 35 * $FreeBSD: src/libexec/tftpd/tftpd.c,v 1.15.2.5 2003/04/06 19:42:56 dwmalone Exp $ 36 * $DragonFly: src/libexec/tftpd/tftpd.c,v 1.2 2003/06/17 04:27:08 dillon Exp $ 37 */ 38 39 /* 40 * Trivial file transfer protocol server. 41 * 42 * This version includes many modifications by Jim Guyton 43 * <guyton@rand-unix>. 44 */ 45 46 #include <sys/param.h> 47 #include <sys/ioctl.h> 48 #include <sys/stat.h> 49 #include <sys/socket.h> 50 #include <sys/types.h> 51 52 #include <netinet/in.h> 53 #include <arpa/tftp.h> 54 #include <arpa/inet.h> 55 56 #include <ctype.h> 57 #include <errno.h> 58 #include <fcntl.h> 59 #include <libutil.h> 60 #include <netdb.h> 61 #include <pwd.h> 62 #include <setjmp.h> 63 #include <signal.h> 64 #include <stdio.h> 65 #include <stdlib.h> 66 #include <string.h> 67 #include <syslog.h> 68 #include <unistd.h> 69 70 #include "tftpsubs.h" 71 72 #define TIMEOUT 5 73 #define MAX_TIMEOUTS 5 74 75 int peer; 76 int rexmtval = TIMEOUT; 77 int max_rexmtval = 2*TIMEOUT; 78 79 #define PKTSIZE SEGSIZE+4 80 char buf[PKTSIZE]; 81 char ackbuf[PKTSIZE]; 82 struct sockaddr_storage from; 83 int fromlen; 84 85 void tftp(struct tftphdr *, int); 86 static void unmappedaddr(struct sockaddr_in6 *); 87 88 /* 89 * Null-terminated directory prefix list for absolute pathname requests and 90 * search list for relative pathname requests. 91 * 92 * MAXDIRS should be at least as large as the number of arguments that 93 * inetd allows (currently 20). 94 */ 95 #define MAXDIRS 20 96 static struct dirlist { 97 const char *name; 98 int len; 99 } dirs[MAXDIRS+1]; 100 static int suppress_naks; 101 static int logging; 102 static int ipchroot; 103 104 static const char *errtomsg(int); 105 static void nak(int); 106 static void oack(void); 107 108 static void timer(int); 109 static void justquit(int); 110 111 int 112 main(int argc, char *argv[]) 113 { 114 struct tftphdr *tp; 115 int n; 116 int ch, on; 117 struct sockaddr_storage me; 118 int len; 119 char *chroot_dir = NULL; 120 struct passwd *nobody; 121 const char *chuser = "nobody"; 122 123 openlog("tftpd", LOG_PID | LOG_NDELAY, LOG_FTP); 124 while ((ch = getopt(argc, argv, "cClns:u:")) != -1) { 125 switch (ch) { 126 case 'c': 127 ipchroot = 1; 128 break; 129 case 'C': 130 ipchroot = 2; 131 break; 132 case 'l': 133 logging = 1; 134 break; 135 case 'n': 136 suppress_naks = 1; 137 break; 138 case 's': 139 chroot_dir = optarg; 140 break; 141 case 'u': 142 chuser = optarg; 143 break; 144 default: 145 syslog(LOG_WARNING, "ignoring unknown option -%c", ch); 146 } 147 } 148 if (optind < argc) { 149 struct dirlist *dirp; 150 151 /* Get list of directory prefixes. Skip relative pathnames. */ 152 for (dirp = dirs; optind < argc && dirp < &dirs[MAXDIRS]; 153 optind++) { 154 if (argv[optind][0] == '/') { 155 dirp->name = argv[optind]; 156 dirp->len = strlen(dirp->name); 157 dirp++; 158 } 159 } 160 } 161 else if (chroot_dir) { 162 dirs->name = "/"; 163 dirs->len = 1; 164 } 165 if (ipchroot && chroot_dir == NULL) { 166 syslog(LOG_ERR, "-c requires -s"); 167 exit(1); 168 } 169 170 on = 1; 171 if (ioctl(0, FIONBIO, &on) < 0) { 172 syslog(LOG_ERR, "ioctl(FIONBIO): %m"); 173 exit(1); 174 } 175 fromlen = sizeof (from); 176 n = recvfrom(0, buf, sizeof (buf), 0, 177 (struct sockaddr *)&from, &fromlen); 178 if (n < 0) { 179 syslog(LOG_ERR, "recvfrom: %m"); 180 exit(1); 181 } 182 /* 183 * Now that we have read the message out of the UDP 184 * socket, we fork and exit. Thus, inetd will go back 185 * to listening to the tftp port, and the next request 186 * to come in will start up a new instance of tftpd. 187 * 188 * We do this so that inetd can run tftpd in "wait" mode. 189 * The problem with tftpd running in "nowait" mode is that 190 * inetd may get one or more successful "selects" on the 191 * tftp port before we do our receive, so more than one 192 * instance of tftpd may be started up. Worse, if tftpd 193 * break before doing the above "recvfrom", inetd would 194 * spawn endless instances, clogging the system. 195 */ 196 { 197 int pid; 198 int i, j; 199 200 for (i = 1; i < 20; i++) { 201 pid = fork(); 202 if (pid < 0) { 203 sleep(i); 204 /* 205 * flush out to most recently sent request. 206 * 207 * This may drop some request, but those 208 * will be resent by the clients when 209 * they timeout. The positive effect of 210 * this flush is to (try to) prevent more 211 * than one tftpd being started up to service 212 * a single request from a single client. 213 */ 214 j = sizeof from; 215 i = recvfrom(0, buf, sizeof (buf), 0, 216 (struct sockaddr *)&from, &j); 217 if (i > 0) { 218 n = i; 219 fromlen = j; 220 } 221 } else { 222 break; 223 } 224 } 225 if (pid < 0) { 226 syslog(LOG_ERR, "fork: %m"); 227 exit(1); 228 } else if (pid != 0) { 229 exit(0); 230 } 231 } 232 233 /* 234 * Since we exit here, we should do that only after the above 235 * recvfrom to keep inetd from constantly forking should there 236 * be a problem. See the above comment about system clogging. 237 */ 238 if (chroot_dir) { 239 if (ipchroot) { 240 char *tempchroot; 241 struct stat sb; 242 int statret; 243 struct sockaddr_storage ss; 244 char hbuf[NI_MAXHOST]; 245 246 memcpy(&ss, &from, from.ss_len); 247 unmappedaddr((struct sockaddr_in6 *)&ss); 248 getnameinfo((struct sockaddr *)&ss, ss.ss_len, 249 hbuf, sizeof(hbuf), NULL, 0, 250 NI_NUMERICHOST | NI_WITHSCOPEID); 251 asprintf(&tempchroot, "%s/%s", chroot_dir, hbuf); 252 statret = stat(tempchroot, &sb); 253 if ((sb.st_mode & S_IFDIR) && 254 (statret == 0 || (statret == -1 && ipchroot == 1))) 255 chroot_dir = tempchroot; 256 } 257 /* Must get this before chroot because /etc might go away */ 258 if ((nobody = getpwnam(chuser)) == NULL) { 259 syslog(LOG_ERR, "%s: no such user", chuser); 260 exit(1); 261 } 262 if (chroot(chroot_dir)) { 263 syslog(LOG_ERR, "chroot: %s: %m", chroot_dir); 264 exit(1); 265 } 266 chdir( "/" ); 267 setuid(nobody->pw_uid); 268 setgroups(1, &nobody->pw_gid); 269 } 270 271 len = sizeof(me); 272 if (getsockname(0, (struct sockaddr *)&me, &len) == 0) { 273 switch (me.ss_family) { 274 case AF_INET: 275 ((struct sockaddr_in *)&me)->sin_port = 0; 276 break; 277 case AF_INET6: 278 ((struct sockaddr_in6 *)&me)->sin6_port = 0; 279 break; 280 default: 281 /* unsupported */ 282 break; 283 } 284 } else { 285 memset(&me, 0, sizeof(me)); 286 me.ss_family = from.ss_family; 287 me.ss_len = from.ss_len; 288 } 289 alarm(0); 290 close(0); 291 close(1); 292 peer = socket(from.ss_family, SOCK_DGRAM, 0); 293 if (peer < 0) { 294 syslog(LOG_ERR, "socket: %m"); 295 exit(1); 296 } 297 if (bind(peer, (struct sockaddr *)&me, me.ss_len) < 0) { 298 syslog(LOG_ERR, "bind: %m"); 299 exit(1); 300 } 301 if (connect(peer, (struct sockaddr *)&from, from.ss_len) < 0) { 302 syslog(LOG_ERR, "connect: %m"); 303 exit(1); 304 } 305 tp = (struct tftphdr *)buf; 306 tp->th_opcode = ntohs(tp->th_opcode); 307 if (tp->th_opcode == RRQ || tp->th_opcode == WRQ) 308 tftp(tp, n); 309 exit(1); 310 } 311 312 struct formats; 313 int validate_access(char **, int); 314 void xmitfile(struct formats *); 315 void recvfile(struct formats *); 316 317 struct formats { 318 const char *f_mode; 319 int (*f_validate)(char **, int); 320 void (*f_send)(struct formats *); 321 void (*f_recv)(struct formats *); 322 int f_convert; 323 } formats[] = { 324 { "netascii", validate_access, xmitfile, recvfile, 1 }, 325 { "octet", validate_access, xmitfile, recvfile, 0 }, 326 #ifdef notdef 327 { "mail", validate_user, sendmail, recvmail, 1 }, 328 #endif 329 { 0, NULL, NULL, NULL, 0 } 330 }; 331 332 struct options { 333 const char *o_type; 334 char *o_request; 335 int o_reply; /* turn into union if need be */ 336 } options[] = { 337 { "tsize", NULL, 0 }, /* OPT_TSIZE */ 338 { "timeout", NULL, 0 }, /* OPT_TIMEOUT */ 339 { NULL, NULL, 0 } 340 }; 341 342 enum opt_enum { 343 OPT_TSIZE = 0, 344 OPT_TIMEOUT, 345 }; 346 347 /* 348 * Handle initial connection protocol. 349 */ 350 void 351 tftp(struct tftphdr *tp, int size) 352 { 353 char *cp; 354 int i, first = 1, has_options = 0, ecode; 355 struct formats *pf; 356 char *filename, *mode, *option, *ccp; 357 358 filename = cp = tp->th_stuff; 359 again: 360 while (cp < buf + size) { 361 if (*cp == '\0') 362 break; 363 cp++; 364 } 365 if (*cp != '\0') { 366 nak(EBADOP); 367 exit(1); 368 } 369 if (first) { 370 mode = ++cp; 371 first = 0; 372 goto again; 373 } 374 for (cp = mode; *cp; cp++) 375 if (isupper(*cp)) 376 *cp = tolower(*cp); 377 for (pf = formats; pf->f_mode; pf++) 378 if (strcmp(pf->f_mode, mode) == 0) 379 break; 380 if (pf->f_mode == 0) { 381 nak(EBADOP); 382 exit(1); 383 } 384 while (++cp < buf + size) { 385 for (i = 2, ccp = cp; i > 0; ccp++) { 386 if (ccp >= buf + size) { 387 /* 388 * Don't reject the request, just stop trying 389 * to parse the option and get on with it. 390 * Some Apple OpenFirmware versions have 391 * trailing garbage on the end of otherwise 392 * valid requests. 393 */ 394 goto option_fail; 395 } else if (*ccp == '\0') 396 i--; 397 } 398 for (option = cp; *cp; cp++) 399 if (isupper(*cp)) 400 *cp = tolower(*cp); 401 for (i = 0; options[i].o_type != NULL; i++) 402 if (strcmp(option, options[i].o_type) == 0) { 403 options[i].o_request = ++cp; 404 has_options = 1; 405 } 406 cp = ccp-1; 407 } 408 409 option_fail: 410 if (options[OPT_TIMEOUT].o_request) { 411 int to = atoi(options[OPT_TIMEOUT].o_request); 412 if (to < 1 || to > 255) { 413 nak(EBADOP); 414 exit(1); 415 } 416 else if (to <= max_rexmtval) 417 options[OPT_TIMEOUT].o_reply = rexmtval = to; 418 else 419 options[OPT_TIMEOUT].o_request = NULL; 420 } 421 422 ecode = (*pf->f_validate)(&filename, tp->th_opcode); 423 if (has_options) 424 oack(); 425 if (logging) { 426 char hbuf[NI_MAXHOST]; 427 428 getnameinfo((struct sockaddr *)&from, from.ss_len, 429 hbuf, sizeof(hbuf), NULL, 0, 430 NI_WITHSCOPEID); 431 syslog(LOG_INFO, "%s: %s request for %s: %s", hbuf, 432 tp->th_opcode == WRQ ? "write" : "read", 433 filename, errtomsg(ecode)); 434 } 435 if (ecode) { 436 /* 437 * Avoid storms of naks to a RRQ broadcast for a relative 438 * bootfile pathname from a diskless Sun. 439 */ 440 if (suppress_naks && *filename != '/' && ecode == ENOTFOUND) 441 exit(0); 442 nak(ecode); 443 exit(1); 444 } 445 if (tp->th_opcode == WRQ) 446 (*pf->f_recv)(pf); 447 else 448 (*pf->f_send)(pf); 449 exit(0); 450 } 451 452 453 FILE *file; 454 455 /* 456 * Validate file access. Since we 457 * have no uid or gid, for now require 458 * file to exist and be publicly 459 * readable/writable. 460 * If we were invoked with arguments 461 * from inetd then the file must also be 462 * in one of the given directory prefixes. 463 * Note also, full path name must be 464 * given as we have no login directory. 465 */ 466 int 467 validate_access(char **filep, int mode) 468 { 469 struct stat stbuf; 470 int fd; 471 struct dirlist *dirp; 472 static char pathname[MAXPATHLEN]; 473 char *filename = *filep; 474 475 /* 476 * Prevent tricksters from getting around the directory restrictions 477 */ 478 if (strstr(filename, "/../")) 479 return (EACCESS); 480 481 if (*filename == '/') { 482 /* 483 * Allow the request if it's in one of the approved locations. 484 * Special case: check the null prefix ("/") by looking 485 * for length = 1 and relying on the arg. processing that 486 * it's a /. 487 */ 488 for (dirp = dirs; dirp->name != NULL; dirp++) { 489 if (dirp->len == 1 || 490 (!strncmp(filename, dirp->name, dirp->len) && 491 filename[dirp->len] == '/')) 492 break; 493 } 494 /* If directory list is empty, allow access to any file */ 495 if (dirp->name == NULL && dirp != dirs) 496 return (EACCESS); 497 if (stat(filename, &stbuf) < 0) 498 return (errno == ENOENT ? ENOTFOUND : EACCESS); 499 if ((stbuf.st_mode & S_IFMT) != S_IFREG) 500 return (ENOTFOUND); 501 if (mode == RRQ) { 502 if ((stbuf.st_mode & S_IROTH) == 0) 503 return (EACCESS); 504 } else { 505 if ((stbuf.st_mode & S_IWOTH) == 0) 506 return (EACCESS); 507 } 508 } else { 509 int err; 510 511 /* 512 * Relative file name: search the approved locations for it. 513 * Don't allow write requests that avoid directory 514 * restrictions. 515 */ 516 517 if (!strncmp(filename, "../", 3)) 518 return (EACCESS); 519 520 /* 521 * If the file exists in one of the directories and isn't 522 * readable, continue looking. However, change the error code 523 * to give an indication that the file exists. 524 */ 525 err = ENOTFOUND; 526 for (dirp = dirs; dirp->name != NULL; dirp++) { 527 snprintf(pathname, sizeof(pathname), "%s/%s", 528 dirp->name, filename); 529 if (stat(pathname, &stbuf) == 0 && 530 (stbuf.st_mode & S_IFMT) == S_IFREG) { 531 if ((stbuf.st_mode & S_IROTH) != 0) { 532 break; 533 } 534 err = EACCESS; 535 } 536 } 537 if (dirp->name == NULL) 538 return (err); 539 *filep = filename = pathname; 540 } 541 if (options[OPT_TSIZE].o_request) { 542 if (mode == RRQ) 543 options[OPT_TSIZE].o_reply = stbuf.st_size; 544 else 545 /* XXX Allows writes of all sizes. */ 546 options[OPT_TSIZE].o_reply = 547 atoi(options[OPT_TSIZE].o_request); 548 } 549 fd = open(filename, mode == RRQ ? O_RDONLY : O_WRONLY|O_TRUNC); 550 if (fd < 0) 551 return (errno + 100); 552 file = fdopen(fd, (mode == RRQ)? "r":"w"); 553 if (file == NULL) { 554 return errno+100; 555 } 556 return (0); 557 } 558 559 int timeouts; 560 jmp_buf timeoutbuf; 561 562 void 563 timer(int sig __unused) 564 { 565 if (++timeouts > MAX_TIMEOUTS) 566 exit(1); 567 longjmp(timeoutbuf, 1); 568 } 569 570 /* 571 * Send the requested file. 572 */ 573 void 574 xmitfile(struct formats *pf) 575 { 576 struct tftphdr *dp; 577 struct tftphdr *ap; /* ack packet */ 578 int size, n; 579 volatile unsigned short block; 580 581 signal(SIGALRM, timer); 582 dp = r_init(); 583 ap = (struct tftphdr *)ackbuf; 584 block = 1; 585 do { 586 size = readit(file, &dp, pf->f_convert); 587 if (size < 0) { 588 nak(errno + 100); 589 goto abort; 590 } 591 dp->th_opcode = htons((u_short)DATA); 592 dp->th_block = htons((u_short)block); 593 timeouts = 0; 594 (void)setjmp(timeoutbuf); 595 596 send_data: 597 { 598 int i, t = 1; 599 for (i = 0; ; i++){ 600 if (send(peer, dp, size + 4, 0) != size + 4) { 601 sleep(t); 602 t = (t < 32) ? t<< 1 : t; 603 if (i >= 12) { 604 syslog(LOG_ERR, "write: %m"); 605 goto abort; 606 } 607 } 608 break; 609 } 610 } 611 read_ahead(file, pf->f_convert); 612 for ( ; ; ) { 613 alarm(rexmtval); /* read the ack */ 614 n = recv(peer, ackbuf, sizeof (ackbuf), 0); 615 alarm(0); 616 if (n < 0) { 617 syslog(LOG_ERR, "read: %m"); 618 goto abort; 619 } 620 ap->th_opcode = ntohs((u_short)ap->th_opcode); 621 ap->th_block = ntohs((u_short)ap->th_block); 622 623 if (ap->th_opcode == ERROR) 624 goto abort; 625 626 if (ap->th_opcode == ACK) { 627 if (ap->th_block == block) 628 break; 629 /* Re-synchronize with the other side */ 630 (void) synchnet(peer); 631 if (ap->th_block == (block -1)) 632 goto send_data; 633 } 634 635 } 636 block++; 637 } while (size == SEGSIZE); 638 abort: 639 (void) fclose(file); 640 } 641 642 void 643 justquit(int sig __unused) 644 { 645 exit(0); 646 } 647 648 649 /* 650 * Receive a file. 651 */ 652 void 653 recvfile(struct formats *pf) 654 { 655 struct tftphdr *dp; 656 struct tftphdr *ap; /* ack buffer */ 657 int n, size; 658 volatile unsigned short block; 659 660 signal(SIGALRM, timer); 661 dp = w_init(); 662 ap = (struct tftphdr *)ackbuf; 663 block = 0; 664 do { 665 timeouts = 0; 666 ap->th_opcode = htons((u_short)ACK); 667 ap->th_block = htons((u_short)block); 668 block++; 669 (void) setjmp(timeoutbuf); 670 send_ack: 671 if (send(peer, ackbuf, 4, 0) != 4) { 672 syslog(LOG_ERR, "write: %m"); 673 goto abort; 674 } 675 write_behind(file, pf->f_convert); 676 for ( ; ; ) { 677 alarm(rexmtval); 678 n = recv(peer, dp, PKTSIZE, 0); 679 alarm(0); 680 if (n < 0) { /* really? */ 681 syslog(LOG_ERR, "read: %m"); 682 goto abort; 683 } 684 dp->th_opcode = ntohs((u_short)dp->th_opcode); 685 dp->th_block = ntohs((u_short)dp->th_block); 686 if (dp->th_opcode == ERROR) 687 goto abort; 688 if (dp->th_opcode == DATA) { 689 if (dp->th_block == block) { 690 break; /* normal */ 691 } 692 /* Re-synchronize with the other side */ 693 (void) synchnet(peer); 694 if (dp->th_block == (block-1)) 695 goto send_ack; /* rexmit */ 696 } 697 } 698 /* size = write(file, dp->th_data, n - 4); */ 699 size = writeit(file, &dp, n - 4, pf->f_convert); 700 if (size != (n-4)) { /* ahem */ 701 if (size < 0) nak(errno + 100); 702 else nak(ENOSPACE); 703 goto abort; 704 } 705 } while (size == SEGSIZE); 706 write_behind(file, pf->f_convert); 707 (void) fclose(file); /* close data file */ 708 709 ap->th_opcode = htons((u_short)ACK); /* send the "final" ack */ 710 ap->th_block = htons((u_short)(block)); 711 (void) send(peer, ackbuf, 4, 0); 712 713 signal(SIGALRM, justquit); /* just quit on timeout */ 714 alarm(rexmtval); 715 n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */ 716 alarm(0); 717 if (n >= 4 && /* if read some data */ 718 dp->th_opcode == DATA && /* and got a data block */ 719 block == dp->th_block) { /* then my last ack was lost */ 720 (void) send(peer, ackbuf, 4, 0); /* resend final ack */ 721 } 722 abort: 723 return; 724 } 725 726 struct errmsg { 727 int e_code; 728 const char *e_msg; 729 } errmsgs[] = { 730 { EUNDEF, "Undefined error code" }, 731 { ENOTFOUND, "File not found" }, 732 { EACCESS, "Access violation" }, 733 { ENOSPACE, "Disk full or allocation exceeded" }, 734 { EBADOP, "Illegal TFTP operation" }, 735 { EBADID, "Unknown transfer ID" }, 736 { EEXISTS, "File already exists" }, 737 { ENOUSER, "No such user" }, 738 { EOPTNEG, "Option negotiation" }, 739 { -1, 0 } 740 }; 741 742 static const char * 743 errtomsg(int error) 744 { 745 static char ebuf[20]; 746 struct errmsg *pe; 747 if (error == 0) 748 return "success"; 749 for (pe = errmsgs; pe->e_code >= 0; pe++) 750 if (pe->e_code == error) 751 return pe->e_msg; 752 snprintf(ebuf, sizeof(buf), "error %d", error); 753 return ebuf; 754 } 755 756 /* 757 * Send a nak packet (error message). 758 * Error code passed in is one of the 759 * standard TFTP codes, or a UNIX errno 760 * offset by 100. 761 */ 762 static void 763 nak(int error) 764 { 765 struct tftphdr *tp; 766 int length; 767 struct errmsg *pe; 768 769 tp = (struct tftphdr *)buf; 770 tp->th_opcode = htons((u_short)ERROR); 771 tp->th_code = htons((u_short)error); 772 for (pe = errmsgs; pe->e_code >= 0; pe++) 773 if (pe->e_code == error) 774 break; 775 if (pe->e_code < 0) { 776 pe->e_msg = strerror(error - 100); 777 tp->th_code = EUNDEF; /* set 'undef' errorcode */ 778 } 779 strcpy(tp->th_msg, pe->e_msg); 780 length = strlen(pe->e_msg); 781 tp->th_msg[length] = '\0'; 782 length += 5; 783 if (send(peer, buf, length, 0) != length) 784 syslog(LOG_ERR, "nak: %m"); 785 } 786 787 /* translate IPv4 mapped IPv6 address to IPv4 address */ 788 static void 789 unmappedaddr(struct sockaddr_in6 *sin6) 790 { 791 struct sockaddr_in *sin4; 792 u_int32_t addr; 793 int port; 794 795 if (sin6->sin6_family != AF_INET6 || 796 !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) 797 return; 798 sin4 = (struct sockaddr_in *)sin6; 799 addr = *(u_int32_t *)&sin6->sin6_addr.s6_addr[12]; 800 port = sin6->sin6_port; 801 memset(sin4, 0, sizeof(struct sockaddr_in)); 802 sin4->sin_addr.s_addr = addr; 803 sin4->sin_port = port; 804 sin4->sin_family = AF_INET; 805 sin4->sin_len = sizeof(struct sockaddr_in); 806 } 807 808 /* 809 * Send an oack packet (option acknowledgement). 810 */ 811 static void 812 oack(void) 813 { 814 struct tftphdr *tp, *ap; 815 int size, i, n; 816 char *bp; 817 818 tp = (struct tftphdr *)buf; 819 bp = buf + 2; 820 size = sizeof(buf) - 2; 821 tp->th_opcode = htons((u_short)OACK); 822 for (i = 0; options[i].o_type != NULL; i++) { 823 if (options[i].o_request) { 824 n = snprintf(bp, size, "%s%c%d", options[i].o_type, 825 0, options[i].o_reply); 826 bp += n+1; 827 size -= n+1; 828 if (size < 0) { 829 syslog(LOG_ERR, "oack: buffer overflow"); 830 exit(1); 831 } 832 } 833 } 834 size = bp - buf; 835 ap = (struct tftphdr *)ackbuf; 836 signal(SIGALRM, timer); 837 timeouts = 0; 838 839 (void)setjmp(timeoutbuf); 840 if (send(peer, buf, size, 0) != size) { 841 syslog(LOG_INFO, "oack: %m"); 842 exit(1); 843 } 844 845 for (;;) { 846 alarm(rexmtval); 847 n = recv(peer, ackbuf, sizeof (ackbuf), 0); 848 alarm(0); 849 if (n < 0) { 850 syslog(LOG_ERR, "recv: %m"); 851 exit(1); 852 } 853 ap->th_opcode = ntohs((u_short)ap->th_opcode); 854 ap->th_block = ntohs((u_short)ap->th_block); 855 if (ap->th_opcode == ERROR) 856 exit(1); 857 if (ap->th_opcode == ACK && ap->th_block == 0) 858 break; 859 } 860 } 861