Sweep-fix man page section order to match mdoc(7), part 1/5.
[dragonfly.git] / libexec / tftpd / tftpd.c
CommitLineData
984263bc
MD
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.
1de703da
MD
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 $
3412cacb 36 * $DragonFly: src/libexec/tftpd/tftpd.c,v 1.3 2003/11/20 14:32:17 eirikn Exp $
984263bc
MD
37 */
38
984263bc
MD
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
75int peer;
76int rexmtval = TIMEOUT;
77int max_rexmtval = 2*TIMEOUT;
78
79#define PKTSIZE SEGSIZE+4
80char buf[PKTSIZE];
81char ackbuf[PKTSIZE];
82struct sockaddr_storage from;
83int fromlen;
84
85void tftp(struct tftphdr *, int);
86static 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
96static struct dirlist {
97 const char *name;
98 int len;
99} dirs[MAXDIRS+1];
100static int suppress_naks;
101static int logging;
102static int ipchroot;
103
104static const char *errtomsg(int);
105static void nak(int);
106static void oack(void);
107
108static void timer(int);
109static void justquit(int);
110
111int
112main(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
312struct formats;
313int validate_access(char **, int);
314void xmitfile(struct formats *);
315void recvfile(struct formats *);
316
317struct 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
332struct 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
342enum opt_enum {
343 OPT_TSIZE = 0,
344 OPT_TIMEOUT,
345};
346
347/*
348 * Handle initial connection protocol.
349 */
350void
351tftp(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;
3412cacb 357 char fnbuf[MAXPATHLEN];
984263bc 358
3412cacb 359 cp = tp->th_stuff;
984263bc
MD
360again:
361 while (cp < buf + size) {
362 if (*cp == '\0')
363 break;
364 cp++;
365 }
366 if (*cp != '\0') {
367 nak(EBADOP);
368 exit(1);
369 }
3412cacb
EN
370 i = cp - tp->th_stuff;
371 if (i >= sizeof(fnbuf)) {
372 nak(EBADOP);
373 exit(1);
374 }
375 memcpy(fnbuf, tp->th_stuff, i);
376 fnbuf[i] = '\0';
377 filename = fnbuf;
984263bc
MD
378 if (first) {
379 mode = ++cp;
380 first = 0;
381 goto again;
382 }
383 for (cp = mode; *cp; cp++)
384 if (isupper(*cp))
385 *cp = tolower(*cp);
386 for (pf = formats; pf->f_mode; pf++)
387 if (strcmp(pf->f_mode, mode) == 0)
388 break;
389 if (pf->f_mode == 0) {
390 nak(EBADOP);
391 exit(1);
392 }
393 while (++cp < buf + size) {
394 for (i = 2, ccp = cp; i > 0; ccp++) {
395 if (ccp >= buf + size) {
396 /*
397 * Don't reject the request, just stop trying
398 * to parse the option and get on with it.
399 * Some Apple OpenFirmware versions have
400 * trailing garbage on the end of otherwise
401 * valid requests.
402 */
403 goto option_fail;
404 } else if (*ccp == '\0')
405 i--;
406 }
407 for (option = cp; *cp; cp++)
408 if (isupper(*cp))
409 *cp = tolower(*cp);
410 for (i = 0; options[i].o_type != NULL; i++)
411 if (strcmp(option, options[i].o_type) == 0) {
412 options[i].o_request = ++cp;
413 has_options = 1;
414 }
415 cp = ccp-1;
416 }
417
418option_fail:
419 if (options[OPT_TIMEOUT].o_request) {
420 int to = atoi(options[OPT_TIMEOUT].o_request);
421 if (to < 1 || to > 255) {
422 nak(EBADOP);
423 exit(1);
424 }
425 else if (to <= max_rexmtval)
426 options[OPT_TIMEOUT].o_reply = rexmtval = to;
427 else
428 options[OPT_TIMEOUT].o_request = NULL;
429 }
430
431 ecode = (*pf->f_validate)(&filename, tp->th_opcode);
432 if (has_options)
433 oack();
434 if (logging) {
435 char hbuf[NI_MAXHOST];
436
437 getnameinfo((struct sockaddr *)&from, from.ss_len,
438 hbuf, sizeof(hbuf), NULL, 0,
439 NI_WITHSCOPEID);
440 syslog(LOG_INFO, "%s: %s request for %s: %s", hbuf,
441 tp->th_opcode == WRQ ? "write" : "read",
442 filename, errtomsg(ecode));
443 }
444 if (ecode) {
445 /*
446 * Avoid storms of naks to a RRQ broadcast for a relative
447 * bootfile pathname from a diskless Sun.
448 */
449 if (suppress_naks && *filename != '/' && ecode == ENOTFOUND)
450 exit(0);
451 nak(ecode);
452 exit(1);
453 }
454 if (tp->th_opcode == WRQ)
455 (*pf->f_recv)(pf);
456 else
457 (*pf->f_send)(pf);
458 exit(0);
459}
460
461
462FILE *file;
463
464/*
465 * Validate file access. Since we
466 * have no uid or gid, for now require
467 * file to exist and be publicly
468 * readable/writable.
469 * If we were invoked with arguments
470 * from inetd then the file must also be
471 * in one of the given directory prefixes.
472 * Note also, full path name must be
473 * given as we have no login directory.
474 */
475int
476validate_access(char **filep, int mode)
477{
478 struct stat stbuf;
479 int fd;
480 struct dirlist *dirp;
481 static char pathname[MAXPATHLEN];
482 char *filename = *filep;
483
484 /*
485 * Prevent tricksters from getting around the directory restrictions
486 */
487 if (strstr(filename, "/../"))
488 return (EACCESS);
489
490 if (*filename == '/') {
491 /*
492 * Allow the request if it's in one of the approved locations.
493 * Special case: check the null prefix ("/") by looking
494 * for length = 1 and relying on the arg. processing that
495 * it's a /.
496 */
497 for (dirp = dirs; dirp->name != NULL; dirp++) {
498 if (dirp->len == 1 ||
499 (!strncmp(filename, dirp->name, dirp->len) &&
500 filename[dirp->len] == '/'))
501 break;
502 }
503 /* If directory list is empty, allow access to any file */
504 if (dirp->name == NULL && dirp != dirs)
505 return (EACCESS);
506 if (stat(filename, &stbuf) < 0)
507 return (errno == ENOENT ? ENOTFOUND : EACCESS);
508 if ((stbuf.st_mode & S_IFMT) != S_IFREG)
509 return (ENOTFOUND);
510 if (mode == RRQ) {
511 if ((stbuf.st_mode & S_IROTH) == 0)
512 return (EACCESS);
513 } else {
514 if ((stbuf.st_mode & S_IWOTH) == 0)
515 return (EACCESS);
516 }
517 } else {
518 int err;
519
520 /*
521 * Relative file name: search the approved locations for it.
522 * Don't allow write requests that avoid directory
523 * restrictions.
524 */
525
526 if (!strncmp(filename, "../", 3))
527 return (EACCESS);
528
529 /*
530 * If the file exists in one of the directories and isn't
531 * readable, continue looking. However, change the error code
532 * to give an indication that the file exists.
533 */
534 err = ENOTFOUND;
535 for (dirp = dirs; dirp->name != NULL; dirp++) {
536 snprintf(pathname, sizeof(pathname), "%s/%s",
537 dirp->name, filename);
538 if (stat(pathname, &stbuf) == 0 &&
539 (stbuf.st_mode & S_IFMT) == S_IFREG) {
540 if ((stbuf.st_mode & S_IROTH) != 0) {
541 break;
542 }
543 err = EACCESS;
544 }
545 }
546 if (dirp->name == NULL)
547 return (err);
548 *filep = filename = pathname;
549 }
550 if (options[OPT_TSIZE].o_request) {
551 if (mode == RRQ)
552 options[OPT_TSIZE].o_reply = stbuf.st_size;
553 else
554 /* XXX Allows writes of all sizes. */
555 options[OPT_TSIZE].o_reply =
556 atoi(options[OPT_TSIZE].o_request);
557 }
558 fd = open(filename, mode == RRQ ? O_RDONLY : O_WRONLY|O_TRUNC);
559 if (fd < 0)
560 return (errno + 100);
561 file = fdopen(fd, (mode == RRQ)? "r":"w");
562 if (file == NULL) {
563 return errno+100;
564 }
565 return (0);
566}
567
568int timeouts;
569jmp_buf timeoutbuf;
570
571void
572timer(int sig __unused)
573{
574 if (++timeouts > MAX_TIMEOUTS)
575 exit(1);
576 longjmp(timeoutbuf, 1);
577}
578
579/*
580 * Send the requested file.
581 */
582void
583xmitfile(struct formats *pf)
584{
585 struct tftphdr *dp;
586 struct tftphdr *ap; /* ack packet */
587 int size, n;
588 volatile unsigned short block;
589
590 signal(SIGALRM, timer);
591 dp = r_init();
592 ap = (struct tftphdr *)ackbuf;
593 block = 1;
594 do {
595 size = readit(file, &dp, pf->f_convert);
596 if (size < 0) {
597 nak(errno + 100);
598 goto abort;
599 }
600 dp->th_opcode = htons((u_short)DATA);
601 dp->th_block = htons((u_short)block);
602 timeouts = 0;
603 (void)setjmp(timeoutbuf);
604
605send_data:
606 {
607 int i, t = 1;
608 for (i = 0; ; i++){
609 if (send(peer, dp, size + 4, 0) != size + 4) {
610 sleep(t);
611 t = (t < 32) ? t<< 1 : t;
612 if (i >= 12) {
613 syslog(LOG_ERR, "write: %m");
614 goto abort;
615 }
616 }
617 break;
618 }
619 }
620 read_ahead(file, pf->f_convert);
621 for ( ; ; ) {
622 alarm(rexmtval); /* read the ack */
623 n = recv(peer, ackbuf, sizeof (ackbuf), 0);
624 alarm(0);
625 if (n < 0) {
626 syslog(LOG_ERR, "read: %m");
627 goto abort;
628 }
629 ap->th_opcode = ntohs((u_short)ap->th_opcode);
630 ap->th_block = ntohs((u_short)ap->th_block);
631
632 if (ap->th_opcode == ERROR)
633 goto abort;
634
635 if (ap->th_opcode == ACK) {
636 if (ap->th_block == block)
637 break;
638 /* Re-synchronize with the other side */
639 (void) synchnet(peer);
640 if (ap->th_block == (block -1))
641 goto send_data;
642 }
643
644 }
645 block++;
646 } while (size == SEGSIZE);
647abort:
648 (void) fclose(file);
649}
650
651void
652justquit(int sig __unused)
653{
654 exit(0);
655}
656
657
658/*
659 * Receive a file.
660 */
661void
662recvfile(struct formats *pf)
663{
664 struct tftphdr *dp;
665 struct tftphdr *ap; /* ack buffer */
666 int n, size;
667 volatile unsigned short block;
668
669 signal(SIGALRM, timer);
670 dp = w_init();
671 ap = (struct tftphdr *)ackbuf;
672 block = 0;
673 do {
674 timeouts = 0;
675 ap->th_opcode = htons((u_short)ACK);
676 ap->th_block = htons((u_short)block);
677 block++;
678 (void) setjmp(timeoutbuf);
679send_ack:
680 if (send(peer, ackbuf, 4, 0) != 4) {
681 syslog(LOG_ERR, "write: %m");
682 goto abort;
683 }
684 write_behind(file, pf->f_convert);
685 for ( ; ; ) {
686 alarm(rexmtval);
687 n = recv(peer, dp, PKTSIZE, 0);
688 alarm(0);
689 if (n < 0) { /* really? */
690 syslog(LOG_ERR, "read: %m");
691 goto abort;
692 }
693 dp->th_opcode = ntohs((u_short)dp->th_opcode);
694 dp->th_block = ntohs((u_short)dp->th_block);
695 if (dp->th_opcode == ERROR)
696 goto abort;
697 if (dp->th_opcode == DATA) {
698 if (dp->th_block == block) {
699 break; /* normal */
700 }
701 /* Re-synchronize with the other side */
702 (void) synchnet(peer);
703 if (dp->th_block == (block-1))
704 goto send_ack; /* rexmit */
705 }
706 }
707 /* size = write(file, dp->th_data, n - 4); */
708 size = writeit(file, &dp, n - 4, pf->f_convert);
709 if (size != (n-4)) { /* ahem */
710 if (size < 0) nak(errno + 100);
711 else nak(ENOSPACE);
712 goto abort;
713 }
714 } while (size == SEGSIZE);
715 write_behind(file, pf->f_convert);
716 (void) fclose(file); /* close data file */
717
718 ap->th_opcode = htons((u_short)ACK); /* send the "final" ack */
719 ap->th_block = htons((u_short)(block));
720 (void) send(peer, ackbuf, 4, 0);
721
722 signal(SIGALRM, justquit); /* just quit on timeout */
723 alarm(rexmtval);
724 n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */
725 alarm(0);
726 if (n >= 4 && /* if read some data */
727 dp->th_opcode == DATA && /* and got a data block */
728 block == dp->th_block) { /* then my last ack was lost */
729 (void) send(peer, ackbuf, 4, 0); /* resend final ack */
730 }
731abort:
732 return;
733}
734
735struct errmsg {
736 int e_code;
737 const char *e_msg;
738} errmsgs[] = {
739 { EUNDEF, "Undefined error code" },
740 { ENOTFOUND, "File not found" },
741 { EACCESS, "Access violation" },
742 { ENOSPACE, "Disk full or allocation exceeded" },
743 { EBADOP, "Illegal TFTP operation" },
744 { EBADID, "Unknown transfer ID" },
745 { EEXISTS, "File already exists" },
746 { ENOUSER, "No such user" },
747 { EOPTNEG, "Option negotiation" },
748 { -1, 0 }
749};
750
751static const char *
752errtomsg(int error)
753{
754 static char ebuf[20];
755 struct errmsg *pe;
756 if (error == 0)
757 return "success";
758 for (pe = errmsgs; pe->e_code >= 0; pe++)
759 if (pe->e_code == error)
760 return pe->e_msg;
761 snprintf(ebuf, sizeof(buf), "error %d", error);
762 return ebuf;
763}
764
765/*
766 * Send a nak packet (error message).
767 * Error code passed in is one of the
768 * standard TFTP codes, or a UNIX errno
769 * offset by 100.
770 */
771static void
772nak(int error)
773{
774 struct tftphdr *tp;
775 int length;
776 struct errmsg *pe;
777
778 tp = (struct tftphdr *)buf;
779 tp->th_opcode = htons((u_short)ERROR);
780 tp->th_code = htons((u_short)error);
781 for (pe = errmsgs; pe->e_code >= 0; pe++)
782 if (pe->e_code == error)
783 break;
784 if (pe->e_code < 0) {
785 pe->e_msg = strerror(error - 100);
786 tp->th_code = EUNDEF; /* set 'undef' errorcode */
787 }
788 strcpy(tp->th_msg, pe->e_msg);
789 length = strlen(pe->e_msg);
790 tp->th_msg[length] = '\0';
791 length += 5;
792 if (send(peer, buf, length, 0) != length)
793 syslog(LOG_ERR, "nak: %m");
794}
795
796/* translate IPv4 mapped IPv6 address to IPv4 address */
797static void
798unmappedaddr(struct sockaddr_in6 *sin6)
799{
800 struct sockaddr_in *sin4;
801 u_int32_t addr;
802 int port;
803
804 if (sin6->sin6_family != AF_INET6 ||
805 !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
806 return;
807 sin4 = (struct sockaddr_in *)sin6;
808 addr = *(u_int32_t *)&sin6->sin6_addr.s6_addr[12];
809 port = sin6->sin6_port;
810 memset(sin4, 0, sizeof(struct sockaddr_in));
811 sin4->sin_addr.s_addr = addr;
812 sin4->sin_port = port;
813 sin4->sin_family = AF_INET;
814 sin4->sin_len = sizeof(struct sockaddr_in);
815}
816
817/*
818 * Send an oack packet (option acknowledgement).
819 */
820static void
821oack(void)
822{
823 struct tftphdr *tp, *ap;
824 int size, i, n;
825 char *bp;
826
827 tp = (struct tftphdr *)buf;
828 bp = buf + 2;
829 size = sizeof(buf) - 2;
830 tp->th_opcode = htons((u_short)OACK);
831 for (i = 0; options[i].o_type != NULL; i++) {
832 if (options[i].o_request) {
833 n = snprintf(bp, size, "%s%c%d", options[i].o_type,
834 0, options[i].o_reply);
835 bp += n+1;
836 size -= n+1;
837 if (size < 0) {
838 syslog(LOG_ERR, "oack: buffer overflow");
839 exit(1);
840 }
841 }
842 }
843 size = bp - buf;
844 ap = (struct tftphdr *)ackbuf;
845 signal(SIGALRM, timer);
846 timeouts = 0;
847
848 (void)setjmp(timeoutbuf);
849 if (send(peer, buf, size, 0) != size) {
850 syslog(LOG_INFO, "oack: %m");
851 exit(1);
852 }
853
854 for (;;) {
855 alarm(rexmtval);
856 n = recv(peer, ackbuf, sizeof (ackbuf), 0);
857 alarm(0);
858 if (n < 0) {
859 syslog(LOG_ERR, "recv: %m");
860 exit(1);
861 }
862 ap->th_opcode = ntohs((u_short)ap->th_opcode);
863 ap->th_block = ntohs((u_short)ap->th_block);
864 if (ap->th_opcode == ERROR)
865 exit(1);
866 if (ap->th_opcode == ACK && ap->th_block == 0)
867 break;
868 }
869}