tftpd.c revision 1.6 1 1.1 cgd /*
2 1.1 cgd * Copyright (c) 1983 Regents of the University of California.
3 1.1 cgd * All rights reserved.
4 1.1 cgd *
5 1.1 cgd * Redistribution and use in source and binary forms, with or without
6 1.1 cgd * modification, are permitted provided that the following conditions
7 1.1 cgd * are met:
8 1.1 cgd * 1. Redistributions of source code must retain the above copyright
9 1.1 cgd * notice, this list of conditions and the following disclaimer.
10 1.1 cgd * 2. Redistributions in binary form must reproduce the above copyright
11 1.1 cgd * notice, this list of conditions and the following disclaimer in the
12 1.1 cgd * documentation and/or other materials provided with the distribution.
13 1.1 cgd * 3. All advertising materials mentioning features or use of this software
14 1.1 cgd * must display the following acknowledgement:
15 1.1 cgd * This product includes software developed by the University of
16 1.1 cgd * California, Berkeley and its contributors.
17 1.1 cgd * 4. Neither the name of the University nor the names of its contributors
18 1.1 cgd * may be used to endorse or promote products derived from this software
19 1.1 cgd * without specific prior written permission.
20 1.1 cgd *
21 1.1 cgd * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 1.1 cgd * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 1.1 cgd * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 1.1 cgd * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 1.1 cgd * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 1.1 cgd * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 1.1 cgd * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 1.1 cgd * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 1.1 cgd * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 1.1 cgd * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 1.1 cgd * SUCH DAMAGE.
32 1.1 cgd */
33 1.1 cgd
34 1.1 cgd #ifndef lint
35 1.1 cgd char copyright[] =
36 1.1 cgd "@(#) Copyright (c) 1983 Regents of the University of California.\n\
37 1.1 cgd All rights reserved.\n";
38 1.1 cgd #endif /* not lint */
39 1.1 cgd
40 1.1 cgd #ifndef lint
41 1.3 mycroft /*static char sccsid[] = "from: @(#)tftpd.c 5.13 (Berkeley) 2/26/91";*/
42 1.6 mycroft static char rcsid[] = "$Id: tftpd.c,v 1.6 1995/06/03 22:48:30 mycroft Exp $";
43 1.1 cgd #endif /* not lint */
44 1.1 cgd
45 1.1 cgd /*
46 1.1 cgd * Trivial file transfer protocol server.
47 1.1 cgd *
48 1.1 cgd * This version includes many modifications by Jim Guyton <guyton@rand-unix>
49 1.1 cgd */
50 1.1 cgd
51 1.1 cgd #include <sys/types.h>
52 1.1 cgd #include <sys/ioctl.h>
53 1.1 cgd #include <sys/stat.h>
54 1.1 cgd #include <signal.h>
55 1.1 cgd #include <fcntl.h>
56 1.1 cgd
57 1.1 cgd #include <sys/socket.h>
58 1.1 cgd #include <netinet/in.h>
59 1.1 cgd #include <arpa/tftp.h>
60 1.1 cgd #include <netdb.h>
61 1.1 cgd
62 1.1 cgd #include <setjmp.h>
63 1.1 cgd #include <syslog.h>
64 1.1 cgd #include <stdio.h>
65 1.1 cgd #include <errno.h>
66 1.1 cgd #include <ctype.h>
67 1.1 cgd #include <string.h>
68 1.1 cgd #include <stdlib.h>
69 1.1 cgd
70 1.1 cgd #define TIMEOUT 5
71 1.1 cgd
72 1.1 cgd extern int errno;
73 1.5 cgd extern char *__progname;
74 1.2 mycroft struct sockaddr_in s_in = { AF_INET };
75 1.1 cgd int peer;
76 1.1 cgd int rexmtval = TIMEOUT;
77 1.1 cgd int maxtimeout = 5*TIMEOUT;
78 1.1 cgd
79 1.1 cgd #define PKTSIZE SEGSIZE+4
80 1.1 cgd char buf[PKTSIZE];
81 1.1 cgd char ackbuf[PKTSIZE];
82 1.1 cgd struct sockaddr_in from;
83 1.1 cgd int fromlen;
84 1.1 cgd
85 1.1 cgd #define MAXARG 4
86 1.1 cgd char *dirs[MAXARG+1];
87 1.1 cgd
88 1.4 mycroft int secure = 0;
89 1.4 mycroft
90 1.5 cgd static void
91 1.5 cgd usage()
92 1.5 cgd {
93 1.5 cgd syslog(LOG_ERR, "Usage: %s [-s] [directory ...]\n", __progname);
94 1.5 cgd exit(1);
95 1.5 cgd }
96 1.5 cgd
97 1.5 cgd main(argc, argv)
98 1.5 cgd int argc;
99 1.5 cgd char **argv;
100 1.1 cgd {
101 1.1 cgd register struct tftphdr *tp;
102 1.1 cgd register int n = 0;
103 1.1 cgd int on = 1;
104 1.5 cgd int fd = 0;
105 1.5 cgd int c;
106 1.1 cgd
107 1.1 cgd openlog("tftpd", LOG_PID, LOG_DAEMON);
108 1.5 cgd
109 1.5 cgd while ((c = getopt(argc, argv, "s")) != -1)
110 1.5 cgd switch (c) {
111 1.5 cgd case 's':
112 1.5 cgd secure = 1;
113 1.5 cgd break;
114 1.5 cgd
115 1.5 cgd default:
116 1.5 cgd usage();
117 1.5 cgd break;
118 1.5 cgd }
119 1.5 cgd
120 1.5 cgd for (; optind != argc; optind++) {
121 1.4 mycroft if (!secure) {
122 1.4 mycroft if (n >= MAXARG) {
123 1.4 mycroft syslog(LOG_ERR, "too many directories\n");
124 1.4 mycroft exit(1);
125 1.4 mycroft } else
126 1.5 cgd dirs[n++] = argv[optind];
127 1.4 mycroft }
128 1.5 cgd if (chdir(argv[optind])) {
129 1.5 cgd syslog(LOG_ERR, "%s: %m\n", argv[optind]);
130 1.4 mycroft exit(1);
131 1.4 mycroft }
132 1.4 mycroft }
133 1.5 cgd
134 1.4 mycroft if (secure && chroot(".")) {
135 1.4 mycroft syslog(LOG_ERR, "chroot: %m\n");
136 1.4 mycroft exit(1);
137 1.4 mycroft }
138 1.5 cgd
139 1.5 cgd if (ioctl(fd, FIONBIO, &on) < 0) {
140 1.1 cgd syslog(LOG_ERR, "ioctl(FIONBIO): %m\n");
141 1.1 cgd exit(1);
142 1.1 cgd }
143 1.1 cgd fromlen = sizeof (from);
144 1.5 cgd n = recvfrom(fd, buf, sizeof (buf), 0,
145 1.1 cgd (struct sockaddr *)&from, &fromlen);
146 1.1 cgd if (n < 0) {
147 1.1 cgd syslog(LOG_ERR, "recvfrom: %m\n");
148 1.1 cgd exit(1);
149 1.1 cgd }
150 1.1 cgd /*
151 1.1 cgd * Now that we have read the message out of the UDP
152 1.1 cgd * socket, we fork and exit. Thus, inetd will go back
153 1.1 cgd * to listening to the tftp port, and the next request
154 1.1 cgd * to come in will start up a new instance of tftpd.
155 1.1 cgd *
156 1.1 cgd * We do this so that inetd can run tftpd in "wait" mode.
157 1.1 cgd * The problem with tftpd running in "nowait" mode is that
158 1.1 cgd * inetd may get one or more successful "selects" on the
159 1.1 cgd * tftp port before we do our receive, so more than one
160 1.1 cgd * instance of tftpd may be started up. Worse, if tftpd
161 1.1 cgd * break before doing the above "recvfrom", inetd would
162 1.1 cgd * spawn endless instances, clogging the system.
163 1.1 cgd */
164 1.1 cgd {
165 1.1 cgd int pid;
166 1.1 cgd int i, j;
167 1.1 cgd
168 1.1 cgd for (i = 1; i < 20; i++) {
169 1.1 cgd pid = fork();
170 1.1 cgd if (pid < 0) {
171 1.1 cgd sleep(i);
172 1.1 cgd /*
173 1.1 cgd * flush out to most recently sent request.
174 1.1 cgd *
175 1.1 cgd * This may drop some request, but those
176 1.1 cgd * will be resent by the clients when
177 1.1 cgd * they timeout. The positive effect of
178 1.1 cgd * this flush is to (try to) prevent more
179 1.1 cgd * than one tftpd being started up to service
180 1.1 cgd * a single request from a single client.
181 1.1 cgd */
182 1.1 cgd j = sizeof from;
183 1.5 cgd i = recvfrom(fd, buf, sizeof (buf), 0,
184 1.1 cgd (struct sockaddr *)&from, &j);
185 1.1 cgd if (i > 0) {
186 1.1 cgd n = i;
187 1.1 cgd fromlen = j;
188 1.1 cgd }
189 1.1 cgd } else {
190 1.1 cgd break;
191 1.1 cgd }
192 1.1 cgd }
193 1.1 cgd if (pid < 0) {
194 1.1 cgd syslog(LOG_ERR, "fork: %m\n");
195 1.1 cgd exit(1);
196 1.1 cgd } else if (pid != 0) {
197 1.1 cgd exit(0);
198 1.1 cgd }
199 1.1 cgd }
200 1.6 mycroft from.sin_len = sizeof(struct sockaddr_in);
201 1.1 cgd from.sin_family = AF_INET;
202 1.1 cgd alarm(0);
203 1.5 cgd close(fd);
204 1.1 cgd close(1);
205 1.1 cgd peer = socket(AF_INET, SOCK_DGRAM, 0);
206 1.1 cgd if (peer < 0) {
207 1.1 cgd syslog(LOG_ERR, "socket: %m\n");
208 1.1 cgd exit(1);
209 1.1 cgd }
210 1.2 mycroft if (bind(peer, (struct sockaddr *)&s_in, sizeof (s_in)) < 0) {
211 1.1 cgd syslog(LOG_ERR, "bind: %m\n");
212 1.1 cgd exit(1);
213 1.1 cgd }
214 1.1 cgd if (connect(peer, (struct sockaddr *)&from, sizeof(from)) < 0) {
215 1.1 cgd syslog(LOG_ERR, "connect: %m\n");
216 1.1 cgd exit(1);
217 1.1 cgd }
218 1.1 cgd tp = (struct tftphdr *)buf;
219 1.1 cgd tp->th_opcode = ntohs(tp->th_opcode);
220 1.1 cgd if (tp->th_opcode == RRQ || tp->th_opcode == WRQ)
221 1.1 cgd tftp(tp, n);
222 1.1 cgd exit(1);
223 1.1 cgd }
224 1.1 cgd
225 1.1 cgd int validate_access();
226 1.1 cgd int sendfile(), recvfile();
227 1.1 cgd
228 1.1 cgd struct formats {
229 1.1 cgd char *f_mode;
230 1.1 cgd int (*f_validate)();
231 1.1 cgd int (*f_send)();
232 1.1 cgd int (*f_recv)();
233 1.1 cgd int f_convert;
234 1.1 cgd } formats[] = {
235 1.1 cgd { "netascii", validate_access, sendfile, recvfile, 1 },
236 1.1 cgd { "octet", validate_access, sendfile, recvfile, 0 },
237 1.1 cgd #ifdef notdef
238 1.1 cgd { "mail", validate_user, sendmail, recvmail, 1 },
239 1.1 cgd #endif
240 1.1 cgd { 0 }
241 1.1 cgd };
242 1.1 cgd
243 1.1 cgd /*
244 1.1 cgd * Handle initial connection protocol.
245 1.1 cgd */
246 1.1 cgd tftp(tp, size)
247 1.1 cgd struct tftphdr *tp;
248 1.1 cgd int size;
249 1.1 cgd {
250 1.1 cgd register char *cp;
251 1.1 cgd int first = 1, ecode;
252 1.1 cgd register struct formats *pf;
253 1.1 cgd char *filename, *mode;
254 1.1 cgd
255 1.1 cgd filename = cp = tp->th_stuff;
256 1.1 cgd again:
257 1.1 cgd while (cp < buf + size) {
258 1.1 cgd if (*cp == '\0')
259 1.1 cgd break;
260 1.1 cgd cp++;
261 1.1 cgd }
262 1.1 cgd if (*cp != '\0') {
263 1.1 cgd nak(EBADOP);
264 1.1 cgd exit(1);
265 1.1 cgd }
266 1.1 cgd if (first) {
267 1.1 cgd mode = ++cp;
268 1.1 cgd first = 0;
269 1.1 cgd goto again;
270 1.1 cgd }
271 1.1 cgd for (cp = mode; *cp; cp++)
272 1.1 cgd if (isupper(*cp))
273 1.1 cgd *cp = tolower(*cp);
274 1.1 cgd for (pf = formats; pf->f_mode; pf++)
275 1.1 cgd if (strcmp(pf->f_mode, mode) == 0)
276 1.1 cgd break;
277 1.1 cgd if (pf->f_mode == 0) {
278 1.1 cgd nak(EBADOP);
279 1.1 cgd exit(1);
280 1.1 cgd }
281 1.1 cgd ecode = (*pf->f_validate)(filename, tp->th_opcode);
282 1.1 cgd if (ecode) {
283 1.1 cgd nak(ecode);
284 1.1 cgd exit(1);
285 1.1 cgd }
286 1.1 cgd if (tp->th_opcode == WRQ)
287 1.1 cgd (*pf->f_recv)(pf);
288 1.1 cgd else
289 1.1 cgd (*pf->f_send)(pf);
290 1.1 cgd exit(0);
291 1.1 cgd }
292 1.1 cgd
293 1.1 cgd
294 1.1 cgd FILE *file;
295 1.1 cgd
296 1.1 cgd /*
297 1.1 cgd * Validate file access. Since we
298 1.1 cgd * have no uid or gid, for now require
299 1.1 cgd * file to exist and be publicly
300 1.1 cgd * readable/writable.
301 1.1 cgd * If we were invoked with arguments
302 1.1 cgd * from inetd then the file must also be
303 1.1 cgd * in one of the given directory prefixes.
304 1.1 cgd * Note also, full path name must be
305 1.1 cgd * given as we have no login directory.
306 1.1 cgd */
307 1.1 cgd validate_access(filename, mode)
308 1.1 cgd char *filename;
309 1.1 cgd int mode;
310 1.1 cgd {
311 1.1 cgd struct stat stbuf;
312 1.1 cgd int fd;
313 1.1 cgd char *cp, **dirp;
314 1.1 cgd
315 1.4 mycroft if (!secure) {
316 1.4 mycroft if (*filename != '/')
317 1.4 mycroft return (EACCESS);
318 1.4 mycroft /*
319 1.4 mycroft * prevent tricksters from getting around the directory
320 1.4 mycroft * restrictions
321 1.4 mycroft */
322 1.4 mycroft for (cp = filename + 1; *cp; cp++)
323 1.4 mycroft if(*cp == '.' && strncmp(cp-1, "/../", 4) == 0)
324 1.4 mycroft return(EACCESS);
325 1.4 mycroft for (dirp = dirs; *dirp; dirp++)
326 1.4 mycroft if (strncmp(filename, *dirp, strlen(*dirp)) == 0)
327 1.4 mycroft break;
328 1.4 mycroft if (*dirp==0 && dirp!=dirs)
329 1.4 mycroft return (EACCESS);
330 1.4 mycroft }
331 1.1 cgd if (stat(filename, &stbuf) < 0)
332 1.1 cgd return (errno == ENOENT ? ENOTFOUND : EACCESS);
333 1.1 cgd if (mode == RRQ) {
334 1.1 cgd if ((stbuf.st_mode&(S_IREAD >> 6)) == 0)
335 1.1 cgd return (EACCESS);
336 1.1 cgd } else {
337 1.1 cgd if ((stbuf.st_mode&(S_IWRITE >> 6)) == 0)
338 1.1 cgd return (EACCESS);
339 1.1 cgd }
340 1.1 cgd fd = open(filename, mode == RRQ ? 0 : 1);
341 1.1 cgd if (fd < 0)
342 1.1 cgd return (errno + 100);
343 1.1 cgd file = fdopen(fd, (mode == RRQ)? "r":"w");
344 1.1 cgd if (file == NULL) {
345 1.1 cgd return errno+100;
346 1.1 cgd }
347 1.1 cgd return (0);
348 1.1 cgd }
349 1.1 cgd
350 1.1 cgd int timeout;
351 1.1 cgd jmp_buf timeoutbuf;
352 1.1 cgd
353 1.1 cgd void
354 1.1 cgd timer()
355 1.1 cgd {
356 1.1 cgd
357 1.1 cgd timeout += rexmtval;
358 1.1 cgd if (timeout >= maxtimeout)
359 1.1 cgd exit(1);
360 1.1 cgd longjmp(timeoutbuf, 1);
361 1.1 cgd }
362 1.1 cgd
363 1.1 cgd /*
364 1.1 cgd * Send the requested file.
365 1.1 cgd */
366 1.1 cgd sendfile(pf)
367 1.1 cgd struct formats *pf;
368 1.1 cgd {
369 1.1 cgd struct tftphdr *dp, *r_init();
370 1.1 cgd register struct tftphdr *ap; /* ack packet */
371 1.1 cgd register int block = 1, size, n;
372 1.1 cgd
373 1.1 cgd signal(SIGALRM, timer);
374 1.1 cgd dp = r_init();
375 1.1 cgd ap = (struct tftphdr *)ackbuf;
376 1.1 cgd do {
377 1.1 cgd size = readit(file, &dp, pf->f_convert);
378 1.1 cgd if (size < 0) {
379 1.1 cgd nak(errno + 100);
380 1.1 cgd goto abort;
381 1.1 cgd }
382 1.1 cgd dp->th_opcode = htons((u_short)DATA);
383 1.1 cgd dp->th_block = htons((u_short)block);
384 1.1 cgd timeout = 0;
385 1.1 cgd (void) setjmp(timeoutbuf);
386 1.1 cgd
387 1.1 cgd send_data:
388 1.1 cgd if (send(peer, dp, size + 4, 0) != size + 4) {
389 1.1 cgd syslog(LOG_ERR, "tftpd: write: %m\n");
390 1.1 cgd goto abort;
391 1.1 cgd }
392 1.1 cgd read_ahead(file, pf->f_convert);
393 1.1 cgd for ( ; ; ) {
394 1.1 cgd alarm(rexmtval); /* read the ack */
395 1.1 cgd n = recv(peer, ackbuf, sizeof (ackbuf), 0);
396 1.1 cgd alarm(0);
397 1.1 cgd if (n < 0) {
398 1.1 cgd syslog(LOG_ERR, "tftpd: read: %m\n");
399 1.1 cgd goto abort;
400 1.1 cgd }
401 1.1 cgd ap->th_opcode = ntohs((u_short)ap->th_opcode);
402 1.1 cgd ap->th_block = ntohs((u_short)ap->th_block);
403 1.1 cgd
404 1.1 cgd if (ap->th_opcode == ERROR)
405 1.1 cgd goto abort;
406 1.1 cgd
407 1.1 cgd if (ap->th_opcode == ACK) {
408 1.1 cgd if (ap->th_block == block) {
409 1.1 cgd break;
410 1.1 cgd }
411 1.1 cgd /* Re-synchronize with the other side */
412 1.1 cgd (void) synchnet(peer);
413 1.1 cgd if (ap->th_block == (block -1)) {
414 1.1 cgd goto send_data;
415 1.1 cgd }
416 1.1 cgd }
417 1.1 cgd
418 1.1 cgd }
419 1.1 cgd block++;
420 1.1 cgd } while (size == SEGSIZE);
421 1.1 cgd abort:
422 1.1 cgd (void) fclose(file);
423 1.1 cgd }
424 1.1 cgd
425 1.1 cgd void
426 1.1 cgd justquit()
427 1.1 cgd {
428 1.1 cgd exit(0);
429 1.1 cgd }
430 1.1 cgd
431 1.1 cgd
432 1.1 cgd /*
433 1.1 cgd * Receive a file.
434 1.1 cgd */
435 1.1 cgd recvfile(pf)
436 1.1 cgd struct formats *pf;
437 1.1 cgd {
438 1.1 cgd struct tftphdr *dp, *w_init();
439 1.1 cgd register struct tftphdr *ap; /* ack buffer */
440 1.1 cgd register int block = 0, n, size;
441 1.1 cgd
442 1.1 cgd signal(SIGALRM, timer);
443 1.1 cgd dp = w_init();
444 1.1 cgd ap = (struct tftphdr *)ackbuf;
445 1.1 cgd do {
446 1.1 cgd timeout = 0;
447 1.1 cgd ap->th_opcode = htons((u_short)ACK);
448 1.1 cgd ap->th_block = htons((u_short)block);
449 1.1 cgd block++;
450 1.1 cgd (void) setjmp(timeoutbuf);
451 1.1 cgd send_ack:
452 1.1 cgd if (send(peer, ackbuf, 4, 0) != 4) {
453 1.1 cgd syslog(LOG_ERR, "tftpd: write: %m\n");
454 1.1 cgd goto abort;
455 1.1 cgd }
456 1.1 cgd write_behind(file, pf->f_convert);
457 1.1 cgd for ( ; ; ) {
458 1.1 cgd alarm(rexmtval);
459 1.1 cgd n = recv(peer, dp, PKTSIZE, 0);
460 1.1 cgd alarm(0);
461 1.1 cgd if (n < 0) { /* really? */
462 1.1 cgd syslog(LOG_ERR, "tftpd: read: %m\n");
463 1.1 cgd goto abort;
464 1.1 cgd }
465 1.1 cgd dp->th_opcode = ntohs((u_short)dp->th_opcode);
466 1.1 cgd dp->th_block = ntohs((u_short)dp->th_block);
467 1.1 cgd if (dp->th_opcode == ERROR)
468 1.1 cgd goto abort;
469 1.1 cgd if (dp->th_opcode == DATA) {
470 1.1 cgd if (dp->th_block == block) {
471 1.1 cgd break; /* normal */
472 1.1 cgd }
473 1.1 cgd /* Re-synchronize with the other side */
474 1.1 cgd (void) synchnet(peer);
475 1.1 cgd if (dp->th_block == (block-1))
476 1.1 cgd goto send_ack; /* rexmit */
477 1.1 cgd }
478 1.1 cgd }
479 1.1 cgd /* size = write(file, dp->th_data, n - 4); */
480 1.1 cgd size = writeit(file, &dp, n - 4, pf->f_convert);
481 1.1 cgd if (size != (n-4)) { /* ahem */
482 1.1 cgd if (size < 0) nak(errno + 100);
483 1.1 cgd else nak(ENOSPACE);
484 1.1 cgd goto abort;
485 1.1 cgd }
486 1.1 cgd } while (size == SEGSIZE);
487 1.1 cgd write_behind(file, pf->f_convert);
488 1.1 cgd (void) fclose(file); /* close data file */
489 1.1 cgd
490 1.1 cgd ap->th_opcode = htons((u_short)ACK); /* send the "final" ack */
491 1.1 cgd ap->th_block = htons((u_short)(block));
492 1.1 cgd (void) send(peer, ackbuf, 4, 0);
493 1.1 cgd
494 1.1 cgd signal(SIGALRM, justquit); /* just quit on timeout */
495 1.1 cgd alarm(rexmtval);
496 1.1 cgd n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */
497 1.1 cgd alarm(0);
498 1.1 cgd if (n >= 4 && /* if read some data */
499 1.1 cgd dp->th_opcode == DATA && /* and got a data block */
500 1.1 cgd block == dp->th_block) { /* then my last ack was lost */
501 1.1 cgd (void) send(peer, ackbuf, 4, 0); /* resend final ack */
502 1.1 cgd }
503 1.1 cgd abort:
504 1.1 cgd return;
505 1.1 cgd }
506 1.1 cgd
507 1.1 cgd struct errmsg {
508 1.1 cgd int e_code;
509 1.1 cgd char *e_msg;
510 1.1 cgd } errmsgs[] = {
511 1.1 cgd { EUNDEF, "Undefined error code" },
512 1.1 cgd { ENOTFOUND, "File not found" },
513 1.1 cgd { EACCESS, "Access violation" },
514 1.1 cgd { ENOSPACE, "Disk full or allocation exceeded" },
515 1.1 cgd { EBADOP, "Illegal TFTP operation" },
516 1.1 cgd { EBADID, "Unknown transfer ID" },
517 1.1 cgd { EEXISTS, "File already exists" },
518 1.1 cgd { ENOUSER, "No such user" },
519 1.1 cgd { -1, 0 }
520 1.1 cgd };
521 1.1 cgd
522 1.1 cgd /*
523 1.1 cgd * Send a nak packet (error message).
524 1.1 cgd * Error code passed in is one of the
525 1.1 cgd * standard TFTP codes, or a UNIX errno
526 1.1 cgd * offset by 100.
527 1.1 cgd */
528 1.1 cgd nak(error)
529 1.1 cgd int error;
530 1.1 cgd {
531 1.1 cgd register struct tftphdr *tp;
532 1.1 cgd int length;
533 1.1 cgd register struct errmsg *pe;
534 1.1 cgd
535 1.1 cgd tp = (struct tftphdr *)buf;
536 1.1 cgd tp->th_opcode = htons((u_short)ERROR);
537 1.1 cgd tp->th_code = htons((u_short)error);
538 1.1 cgd for (pe = errmsgs; pe->e_code >= 0; pe++)
539 1.1 cgd if (pe->e_code == error)
540 1.1 cgd break;
541 1.1 cgd if (pe->e_code < 0) {
542 1.1 cgd pe->e_msg = strerror(error - 100);
543 1.1 cgd tp->th_code = EUNDEF; /* set 'undef' errorcode */
544 1.1 cgd }
545 1.1 cgd strcpy(tp->th_msg, pe->e_msg);
546 1.1 cgd length = strlen(pe->e_msg);
547 1.1 cgd tp->th_msg[length] = '\0';
548 1.1 cgd length += 5;
549 1.1 cgd if (send(peer, buf, length, 0) != length)
550 1.1 cgd syslog(LOG_ERR, "nak: %m\n");
551 1.1 cgd }
552