xref: /freebsd/usr.bin/tftp/tftp.c (revision 4ed925457ab06e83238a5db33e89ccc94b99a713)
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 
34 #if 0
35 #ifndef lint
36 static char sccsid[] = "@(#)tftp.c	8.1 (Berkeley) 6/6/93";
37 #endif /* not lint */
38 #endif
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 /* Many bug fixes are from Jim Guyton <guyton@rand-unix> */
44 
45 /*
46  * TFTP User Program -- Protocol Machines
47  */
48 #include <sys/types.h>
49 #include <sys/socket.h>
50 #include <sys/time.h>
51 
52 #include <netinet/in.h>
53 
54 #include <arpa/inet.h>
55 #include <arpa/tftp.h>
56 
57 #include <err.h>
58 #include <errno.h>
59 #include <setjmp.h>
60 #include <signal.h>
61 #include <stdio.h>
62 #include <string.h>
63 #include <unistd.h>
64 #include <netdb.h>
65 
66 #include "extern.h"
67 #include "tftpsubs.h"
68 
69 extern  struct sockaddr_storage peeraddr; /* filled in by main */
70 extern  int     f;			/* the opened socket */
71 extern  int     trace;
72 extern  int     verbose;
73 extern  int     rexmtval;
74 extern  int     maxtimeout;
75 extern  volatile int txrx_error;
76 
77 #define PKTSIZE    SEGSIZE+4
78 char    ackbuf[PKTSIZE];
79 int	timeout;
80 jmp_buf	toplevel;
81 jmp_buf	timeoutbuf;
82 
83 static void nak(int, const struct sockaddr *);
84 static int makerequest(int, const char *, struct tftphdr *, const char *);
85 static void printstats(const char *, unsigned long);
86 static void startclock(void);
87 static void stopclock(void);
88 static void timer(int);
89 static void tpacket(const char *, struct tftphdr *, int);
90 static int cmpport(const struct sockaddr *, const struct sockaddr *);
91 
92 /*
93  * Send the requested file.
94  */
95 void
96 xmitfile(int fd, const char *name, const char *mode)
97 {
98 	struct tftphdr *ap;	   /* data and ack packets */
99 	struct tftphdr *dp;
100 	int n;
101 	volatile unsigned short block;
102 	volatile int size, convert;
103 	volatile unsigned long amount;
104 	struct sockaddr_storage from;
105 	socklen_t fromlen;
106 	FILE *file;
107 	struct sockaddr_storage peer;
108 	struct sockaddr_storage serv;	/* valid server port number */
109 
110 	startclock();		/* start stat's clock */
111 	dp = r_init();		/* reset fillbuf/read-ahead code */
112 	ap = (struct tftphdr *)ackbuf;
113 	file = fdopen(fd, "r");
114 	convert = !strcmp(mode, "netascii");
115 	block = 0;
116 	amount = 0;
117 	memcpy(&peer, &peeraddr, peeraddr.ss_len);
118 	memset(&serv, 0, sizeof(serv));
119 
120 	signal(SIGALRM, timer);
121 	do {
122 		if (block == 0)
123 			size = makerequest(WRQ, name, dp, mode) - 4;
124 		else {
125 		/*	size = read(fd, dp->th_data, SEGSIZE);	 */
126 			size = readit(file, &dp, convert);
127 			if (size < 0) {
128 				nak(errno + 100, (struct sockaddr *)&peer);
129 				break;
130 			}
131 			dp->th_opcode = htons((u_short)DATA);
132 			dp->th_block = htons((u_short)block);
133 		}
134 		timeout = 0;
135 		(void) setjmp(timeoutbuf);
136 send_data:
137 		if (trace)
138 			tpacket("sent", dp, size + 4);
139 		n = sendto(f, dp, size + 4, 0,
140 		    (struct sockaddr *)&peer, peer.ss_len);
141 		if (n != size + 4) {
142 			warn("sendto");
143 			txrx_error = 1;
144 			goto abort;
145 		}
146 		read_ahead(file, convert);
147 		for ( ; ; ) {
148 			alarm(rexmtval);
149 			do {
150 				fromlen = sizeof(from);
151 				n = recvfrom(f, ackbuf, sizeof(ackbuf), 0,
152 				    (struct sockaddr *)&from, &fromlen);
153 			} while (n <= 0);
154 			alarm(0);
155 			if (n < 0) {
156 				warn("recvfrom");
157 				txrx_error = 1;
158 				goto abort;
159 			}
160 			if (!serv.ss_family)
161 				serv = from;
162 			else if (!cmpport((struct sockaddr *)&serv,
163 			    (struct sockaddr *)&from)) {
164 				warn("server port mismatch");
165 				txrx_error = 1;
166 				goto abort;
167 			}
168 			peer = from;
169 			if (trace)
170 				tpacket("received", ap, n);
171 			/* should verify packet came from server */
172 			ap->th_opcode = ntohs(ap->th_opcode);
173 			ap->th_block = ntohs(ap->th_block);
174 			if (ap->th_opcode == ERROR) {
175 				printf("Error code %d: %s\n", ap->th_code,
176 					ap->th_msg);
177 				txrx_error = 1;
178 				goto abort;
179 			}
180 			if (ap->th_opcode == ACK) {
181 				int j;
182 
183 				if (ap->th_block == block) {
184 					break;
185 				}
186 				/* On an error, try to synchronize
187 				 * both sides.
188 				 */
189 				j = synchnet(f);
190 				if (j && trace) {
191 					printf("discarded %d packets\n",
192 							j);
193 				}
194 				if (ap->th_block == (block-1)) {
195 					goto send_data;
196 				}
197 			}
198 		}
199 		if (block > 0)
200 			amount += size;
201 		block++;
202 	} while (size == SEGSIZE || block == 1);
203 abort:
204 	fclose(file);
205 	stopclock();
206 	if (amount > 0)
207 		printstats("Sent", amount);
208 }
209 
210 /*
211  * Receive a file.
212  */
213 void
214 recvfile(int fd, const char *name, const char *mode)
215 {
216 	struct tftphdr *ap;
217 	struct tftphdr *dp;
218 	int n;
219 	volatile unsigned short block;
220 	volatile int size, firsttrip;
221 	volatile unsigned long amount;
222 	struct sockaddr_storage from;
223 	socklen_t fromlen;
224 	FILE *file;
225 	volatile int convert;		/* true if converting crlf -> lf */
226 	struct sockaddr_storage peer;
227 	struct sockaddr_storage serv;	/* valid server port number */
228 
229 	startclock();
230 	dp = w_init();
231 	ap = (struct tftphdr *)ackbuf;
232 	file = fdopen(fd, "w");
233 	convert = !strcmp(mode, "netascii");
234 	block = 1;
235 	firsttrip = 1;
236 	amount = 0;
237 	memcpy(&peer, &peeraddr, peeraddr.ss_len);
238 	memset(&serv, 0, sizeof(serv));
239 
240 	signal(SIGALRM, timer);
241 	do {
242 		if (firsttrip) {
243 			size = makerequest(RRQ, name, ap, mode);
244 			firsttrip = 0;
245 		} else {
246 			ap->th_opcode = htons((u_short)ACK);
247 			ap->th_block = htons((u_short)(block));
248 			size = 4;
249 			block++;
250 		}
251 		timeout = 0;
252 		(void) setjmp(timeoutbuf);
253 send_ack:
254 		if (trace)
255 			tpacket("sent", ap, size);
256 		if (sendto(f, ackbuf, size, 0, (struct sockaddr *)&peer,
257 		    peer.ss_len) != size) {
258 			alarm(0);
259 			warn("sendto");
260 			txrx_error = 1;
261 			goto abort;
262 		}
263 		write_behind(file, convert);
264 		for ( ; ; ) {
265 			alarm(rexmtval);
266 			do  {
267 				fromlen = sizeof(from);
268 				n = recvfrom(f, dp, PKTSIZE, 0,
269 				    (struct sockaddr *)&from, &fromlen);
270 			} while (n <= 0);
271 			alarm(0);
272 			if (n < 0) {
273 				warn("recvfrom");
274 				txrx_error = 1;
275 				goto abort;
276 			}
277 			if (!serv.ss_family)
278 				serv = from;
279 			else if (!cmpport((struct sockaddr *)&serv,
280 			    (struct sockaddr *)&from)) {
281 				warn("server port mismatch");
282 				txrx_error = 1;
283 				goto abort;
284 			}
285 			peer = from;
286 			if (trace)
287 				tpacket("received", dp, n);
288 			/* should verify client address */
289 			dp->th_opcode = ntohs(dp->th_opcode);
290 			dp->th_block = ntohs(dp->th_block);
291 			if (dp->th_opcode == ERROR) {
292 				printf("Error code %d: %s\n", dp->th_code,
293 					dp->th_msg);
294 				txrx_error = 1;
295 				goto abort;
296 			}
297 			if (dp->th_opcode == DATA) {
298 				int j;
299 
300 				if (dp->th_block == block) {
301 					break;		/* have next packet */
302 				}
303 				/* On an error, try to synchronize
304 				 * both sides.
305 				 */
306 				j = synchnet(f);
307 				if (j && trace) {
308 					printf("discarded %d packets\n", j);
309 				}
310 				if (dp->th_block == (block-1)) {
311 					goto send_ack;	/* resend ack */
312 				}
313 			}
314 		}
315 	/*	size = write(fd, dp->th_data, n - 4); */
316 		size = writeit(file, &dp, n - 4, convert);
317 		if (size < 0) {
318 			nak(errno + 100, (struct sockaddr *)&peer);
319 			break;
320 		}
321 		amount += size;
322 	} while (size == SEGSIZE);
323 abort:						/* ok to ack, since user */
324 	ap->th_opcode = htons((u_short)ACK);	/* has seen err msg */
325 	ap->th_block = htons((u_short)block);
326 	(void) sendto(f, ackbuf, 4, 0, (struct sockaddr *)&peer,
327 	    peer.ss_len);
328 	write_behind(file, convert);		/* flush last buffer */
329 	fclose(file);
330 	stopclock();
331 	if (amount > 0)
332 		printstats("Received", amount);
333 }
334 
335 static int
336 makerequest(int request, const char *name, struct tftphdr *tp, const char *mode)
337 {
338 	char *cp;
339 
340 	tp->th_opcode = htons((u_short)request);
341 	cp = tp->th_stuff;
342 	strcpy(cp, name);
343 	cp += strlen(name);
344 	*cp++ = '\0';
345 	strcpy(cp, mode);
346 	cp += strlen(mode);
347 	*cp++ = '\0';
348 	return (cp - (char *)tp);
349 }
350 
351 struct errmsg {
352 	int	e_code;
353 	const char	*e_msg;
354 } errmsgs[] = {
355 	{ EUNDEF,	"Undefined error code" },
356 	{ ENOTFOUND,	"File not found" },
357 	{ EACCESS,	"Access violation" },
358 	{ ENOSPACE,	"Disk full or allocation exceeded" },
359 	{ EBADOP,	"Illegal TFTP operation" },
360 	{ EBADID,	"Unknown transfer ID" },
361 	{ EEXISTS,	"File already exists" },
362 	{ ENOUSER,	"No such user" },
363 	{ -1,		0 }
364 };
365 
366 /*
367  * Send a nak packet (error message).
368  * Error code passed in is one of the
369  * standard TFTP codes, or a UNIX errno
370  * offset by 100.
371  */
372 static void
373 nak(int error, const struct sockaddr *peer)
374 {
375 	struct errmsg *pe;
376 	struct tftphdr *tp;
377 	int length;
378 
379 	tp = (struct tftphdr *)ackbuf;
380 	tp->th_opcode = htons((u_short)ERROR);
381 	tp->th_code = htons((u_short)error);
382 	for (pe = errmsgs; pe->e_code >= 0; pe++)
383 		if (pe->e_code == error)
384 			break;
385 	if (pe->e_code < 0) {
386 		pe->e_msg = strerror(error - 100);
387 		tp->th_code = EUNDEF;
388 	}
389 	strcpy(tp->th_msg, pe->e_msg);
390 	length = strlen(pe->e_msg) + 4;
391 	if (trace)
392 		tpacket("sent", tp, length);
393 	if (sendto(f, ackbuf, length, 0, peer, peer->sa_len) != length)
394 		warn("nak");
395 }
396 
397 static void
398 tpacket(const char *s, struct tftphdr *tp, int n)
399 {
400 	static const char *opcodes[] =
401 	   { "#0", "RRQ", "WRQ", "DATA", "ACK", "ERROR" };
402 	char *cp, *file;
403 	u_short op = ntohs(tp->th_opcode);
404 
405 	if (op < RRQ || op > ERROR)
406 		printf("%s opcode=%x ", s, op);
407 	else
408 		printf("%s %s ", s, opcodes[op]);
409 	switch (op) {
410 
411 	case RRQ:
412 	case WRQ:
413 		n -= 2;
414 		file = cp = tp->th_stuff;
415 		cp = index(cp, '\0');
416 		printf("<file=%s, mode=%s>\n", file, cp + 1);
417 		break;
418 
419 	case DATA:
420 		printf("<block=%d, %d bytes>\n", ntohs(tp->th_block), n - 4);
421 		break;
422 
423 	case ACK:
424 		printf("<block=%d>\n", ntohs(tp->th_block));
425 		break;
426 
427 	case ERROR:
428 		printf("<code=%d, msg=%s>\n", ntohs(tp->th_code), tp->th_msg);
429 		break;
430 	}
431 }
432 
433 struct timeval tstart;
434 struct timeval tstop;
435 
436 static void
437 startclock(void)
438 {
439 
440 	(void)gettimeofday(&tstart, NULL);
441 }
442 
443 static void
444 stopclock(void)
445 {
446 
447 	(void)gettimeofday(&tstop, NULL);
448 }
449 
450 static void
451 printstats(const char *direction, unsigned long amount)
452 {
453 	double delta;
454 			/* compute delta in 1/10's second units */
455 	delta = ((tstop.tv_sec*10.)+(tstop.tv_usec/100000)) -
456 		((tstart.tv_sec*10.)+(tstart.tv_usec/100000));
457 	delta = delta/10.;      /* back to seconds */
458 	printf("%s %ld bytes in %.1f seconds", direction, amount, delta);
459 	if (verbose)
460 		printf(" [%.0f bits/sec]", (amount*8.)/delta);
461 	putchar('\n');
462 }
463 
464 static void
465 timer(int sig __unused)
466 {
467 
468 	timeout += rexmtval;
469 	if (timeout >= maxtimeout) {
470 		printf("Transfer timed out.\n");
471 		longjmp(toplevel, -1);
472 	}
473         txrx_error = 1;
474 	longjmp(timeoutbuf, 1);
475 }
476 
477 static int
478 cmpport(const struct sockaddr *sa, const struct sockaddr *sb)
479 {
480 	char a[NI_MAXSERV], b[NI_MAXSERV];
481 
482 	if (getnameinfo(sa, sa->sa_len, NULL, 0, a, sizeof(a), NI_NUMERICSERV))
483 		return 0;
484 	if (getnameinfo(sb, sb->sa_len, NULL, 0, b, sizeof(b), NI_NUMERICSERV))
485 		return 0;
486 	if (strcmp(a, b) != 0)
487 		return 0;
488 
489 	return 1;
490 }
491