1 /* vi: set sw=4 ts=4: */
2 /* -------------------------------------------------------------------------
5 * A simple tftp client for busybox.
6 * Tries to follow RFC1350.
7 * Only "octet" mode supported.
8 * Optional blocksize negotiation (RFC2347 + RFC2348)
10 * Copyright (C) 2001 Magnus Damm <damm@opensource.se>
12 * Parts of the code based on:
14 * atftp: Copyright (C) 2000 Jean-Pierre Lefebvre <helix@step.polymtl.ca>
15 * and Remi Lefebvre <remi@debian.org>
17 * utftp: Copyright (C) 1999 Uwe Ohse <uwe@ohse.de>
19 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
20 * ------------------------------------------------------------------------- */
25 #if ENABLE_FEATURE_TFTP_GET || ENABLE_FEATURE_TFTP_PUT
27 #define TFTP_BLOCKSIZE_DEFAULT 512 /* according to RFC 1350, don't change */
28 #define TFTP_TIMEOUT 5 /* seconds */
29 #define TFTP_NUM_RETRIES 5 /* number of retries */
31 /* opcodes we support */
39 #if ENABLE_FEATURE_TFTP_GET && !ENABLE_FEATURE_TFTP_PUT
40 #define USE_GETPUT(...)
41 #define CMD_GET(cmd) 1
42 #define CMD_PUT(cmd) 0
43 #elif !ENABLE_FEATURE_TFTP_GET && ENABLE_FEATURE_TFTP_PUT
44 #define USE_GETPUT(...)
45 #define CMD_GET(cmd) 0
46 #define CMD_PUT(cmd) 1
48 #define USE_GETPUT(...) __VA_ARGS__
49 /* masks coming from getpot32 */
50 #define CMD_GET(cmd) ((cmd) & 1)
51 #define CMD_PUT(cmd) ((cmd) & 2)
53 /* NB: in the code below
54 * CMD_GET(cmd) and CMD_PUT(cmd) are mutually exclusive
58 #if ENABLE_FEATURE_TFTP_BLOCKSIZE
60 static int tftp_blocksize_check(int blocksize, int bufsize)
62 /* Check if the blocksize is valid:
63 * RFC2348 says between 8 and 65464,
64 * but our implementation makes it impossible
65 * to use blocksizes smaller than 22 octets.
68 if ((bufsize && (blocksize > bufsize))
69 || (blocksize < 8) || (blocksize > 65564)
71 bb_error_msg("bad blocksize");
78 static char *tftp_option_get(char *buf, int len, const char *option)
85 /* Make sure the options are terminated correctly */
86 for (k = 0; k < len; k++) {
94 if (strcasecmp(buf, option) == 0) {
97 } else if (opt_found) {
112 static int tftp( USE_GETPUT(const int cmd,)
113 len_and_sockaddr *peer_lsa,
114 const char *remotefile, const int localfd,
115 unsigned port, int tftp_bufsize)
122 USE_FEATURE_TFTP_BLOCKSIZE(smallint want_option_ack = 0;)
123 smallint finished = 0;
125 uint16_t block_nr = 1;
127 int timeout = TFTP_NUM_RETRIES;
131 len_and_sockaddr *const from = alloca(offsetof(len_and_sockaddr, sa) + peer_lsa->len);
133 /* Can't use RESERVE_CONFIG_BUFFER here since the allocation
134 * size varies meaning BUFFERS_GO_ON_STACK would fail */
135 /* We must keep the transmit and receive buffers seperate */
136 /* In case we rcv a garbage pkt and we need to rexmit the last pkt */
137 char *xbuf = xmalloc(tftp_bufsize += 4);
138 char *rbuf = xmalloc(tftp_bufsize);
140 port = org_port = htons(port);
142 socketfd = xsocket(peer_lsa->sa.sa_family, SOCK_DGRAM, 0);
150 /* add filename and mode */
151 /* fill in packet if the filename fits into xbuf */
152 len = strlen(remotefile) + 1;
153 if (2 + len + sizeof("octet") >= tftp_bufsize) {
154 bb_error_msg("remote filename is too long");
157 strcpy(cp, remotefile);
159 /* add "mode" part of the package */
161 cp += sizeof("octet");
163 #if ENABLE_FEATURE_TFTP_BLOCKSIZE
164 len = tftp_bufsize - 4; /* data block size */
165 if (len != TFTP_BLOCKSIZE_DEFAULT) {
166 /* rfc2348 says that 65464 is a max allowed value */
167 if ((&xbuf[tftp_bufsize - 1] - cp) < sizeof("blksize NNNNN")) {
168 bb_error_msg("remote filename is too long");
171 /* add "blksize", <nul>, blocksize */
172 strcpy(cp, "blksize");
173 cp += sizeof("blksize");
174 cp += snprintf(cp, 6, "%d", len) + 1;
178 /* First packet is built, so skip packet generation */
181 /* Using mostly goto's - continue/break will be less clear
182 * in where we actually jump to */
185 /* Build ACK or DATA */
187 *((uint16_t*)cp) = htons(block_nr);
193 len = full_read(localfd, cp, tftp_bufsize - 4);
195 bb_perror_msg(bb_msg_read_error);
198 if (len != (tftp_bufsize - 4)) {
205 *((uint16_t*)xbuf) = htons(opcode); /* fill in opcode part */
206 send_len = cp - xbuf;
207 /* NB: send_len value is preserved in code below
208 * for potential resend */
210 #if ENABLE_DEBUG_TFTP
211 fprintf(stderr, "sending %u bytes\n", send_len);
212 for (cp = xbuf; cp < &xbuf[send_len]; cp++)
213 fprintf(stderr, "%02x ", (unsigned char) *cp);
214 fprintf(stderr, "\n");
216 xsendto(socketfd, xbuf, send_len, &peer_lsa->sa, peer_lsa->len);
217 /* Was it final ACK? then exit */
218 if (finished && (opcode == TFTP_ACK))
221 timeout = TFTP_NUM_RETRIES; /* re-initialize */
224 tv.tv_sec = TFTP_TIMEOUT;
227 FD_SET(socketfd, &rfds);
228 switch (select(socketfd + 1, &rfds, NULL, NULL, &tv)) {
231 from->len = peer_lsa->len;
232 memset(&from->sa, 0, peer_lsa->len);
233 len = recvfrom(socketfd, rbuf, tftp_bufsize, 0,
234 &from->sa, &from->len);
236 bb_perror_msg("recvfrom");
239 from_port = get_nport(&from->sa);
240 if (port == org_port) {
241 /* Our first query went to port 69
242 * but reply will come from different one.
243 * Remember and use this new port */
245 set_nport(peer_lsa, from_port);
247 if (port != from_port)
253 bb_error_msg("last timeout");
256 bb_error_msg("last timeout" + 5);
257 goto send_again; /* resend last sent pkt */
259 bb_perror_msg("select");
263 /* Process recv'ed packet */
264 opcode = ntohs( ((uint16_t*)rbuf)[0] );
265 recv_blk = ntohs( ((uint16_t*)rbuf)[1] );
267 #if ENABLE_DEBUG_TFTP
268 fprintf(stderr, "received %d bytes: %04x %04x\n", len, opcode, recv_blk);
271 if (opcode == TFTP_ERROR) {
272 static const char *const errcode_str[] = {
277 "illegal TFTP operation",
278 "unknown transfer id",
279 "file already exists",
283 enum { NUM_ERRCODE = sizeof(errcode_str) / sizeof(errcode_str[0]) };
284 const char *msg = "";
286 if (rbuf[4] != '\0') {
288 rbuf[tftp_bufsize - 1] = '\0';
289 } else if (recv_blk < NUM_ERRCODE) {
290 msg = errcode_str[recv_blk];
292 bb_error_msg("server error: (%u) %s", recv_blk, msg);
296 #if ENABLE_FEATURE_TFTP_BLOCKSIZE
297 if (want_option_ack) {
300 if (opcode == TFTP_OACK) {
301 /* server seems to support options */
304 res = tftp_option_get(&rbuf[2], len - 2, "blksize");
306 int blksize = xatoi_u(res);
307 if (!tftp_blocksize_check(blksize, tftp_bufsize - 4)) {
308 /* send ERROR 8 to server... */
309 /* htons can be impossible to use in const initializer: */
310 /*static const uint16_t error_8[2] = { htons(TFTP_ERROR), htons(8) };*/
311 /* thus we open-code big-endian layout */
312 static const char error_8[4] = { 0,TFTP_ERROR, 0,8 };
313 xsendto(socketfd, error_8, 4, &peer_lsa->sa, peer_lsa->len);
314 bb_error_msg("server proposes bad blksize %d, exiting", blksize);
317 #if ENABLE_DEBUG_TFTP
318 fprintf(stderr, "using blksize %u\n",
321 tftp_bufsize = blksize + 4;
322 /* Send ACK for OACK ("block" no: 0) */
327 * "An option not acknowledged by the server
328 * must be ignored by the client and server
329 * as if it were never requested." */
332 bb_error_msg("blksize is not supported by server"
333 " - reverting to 512");
334 tftp_bufsize = TFTP_BLOCKSIZE_DEFAULT + 4;
337 /* block_nr is already advanced to next block# we expect
338 * to get / block# we are about to send next time */
340 if (CMD_GET(cmd) && (opcode == TFTP_DATA)) {
341 if (recv_blk == block_nr) {
342 len = full_write(localfd, &rbuf[4], len - 4);
344 bb_perror_msg(bb_msg_write_error);
347 if (len != (tftp_bufsize - 4)) {
350 continue; /* send ACK */
352 if (recv_blk == (block_nr - 1)) {
353 /* Server lost our TFTP_ACK. Resend it */
359 if (CMD_PUT(cmd) && (opcode == TFTP_ACK)) {
360 /* did server ACK our last DATA pkt? */
361 if (recv_blk == (uint16_t) (block_nr - 1)) {
364 continue; /* send next block */
367 /* Awww... recv'd packet is not recognized! */
369 /* why recv_again? - rfc1123 says:
370 * "The sender (i.e., the side originating the DATA packets)
371 * must never resend the current DATA packet on receipt
372 * of a duplicate ACK".
373 * DATA pkts are resent ONLY on timeout.
374 * Thus "goto send_again" will ba a bad mistake above.
376 * http://en.wikipedia.org/wiki/Sorcerer's_Apprentice_Syndrome
380 if (ENABLE_FEATURE_CLEAN_UP) {
385 return finished == 0; /* returns 1 on failure */
388 int tftp_main(int argc, char **argv);
389 int tftp_main(int argc, char **argv)
391 len_and_sockaddr *peer_lsa;
392 const char *localfile = NULL;
393 const char *remotefile = NULL;
394 #if ENABLE_FEATURE_TFTP_BLOCKSIZE
395 const char *sblocksize = NULL;
402 int blocksize = TFTP_BLOCKSIZE_DEFAULT;
404 /* -p or -g is mandatory, and they are mutually exclusive */
405 opt_complementary = "" USE_FEATURE_TFTP_GET("g:") USE_FEATURE_TFTP_PUT("p:")
406 USE_GETPUT("?g--p:p--g");
408 USE_GETPUT(cmd =) getopt32(argc, argv,
409 USE_FEATURE_TFTP_GET("g") USE_FEATURE_TFTP_PUT("p")
410 "l:r:" USE_FEATURE_TFTP_BLOCKSIZE("b:"),
411 &localfile, &remotefile
412 USE_FEATURE_TFTP_BLOCKSIZE(, &sblocksize));
417 flags = O_WRONLY | O_CREAT | O_TRUNC;
419 #if ENABLE_FEATURE_TFTP_BLOCKSIZE
421 blocksize = xatoi_u(sblocksize);
422 if (!tftp_blocksize_check(blocksize, 0)) {
429 localfile = remotefile;
431 remotefile = localfile;
432 /* Error if filename or host is not known */
433 if (!remotefile || !argv[0])
436 fd = CMD_GET(cmd) ? STDOUT_FILENO : STDIN_FILENO;
437 if (!LONE_DASH(localfile)) {
438 fd = xopen(localfile, flags);
441 port = bb_lookup_port(argv[1], "udp", 69);
442 peer_lsa = xhost2sockaddr(argv[0], port);
444 #if ENABLE_DEBUG_TFTP
445 fprintf(stderr, "using server '%s', remotefile '%s', localfile '%s'\n",
446 xmalloc_sockaddr2dotted(&peer_lsa->sa, peer_lsa->len),
447 remotefile, localfile);
450 result = tftp( USE_GETPUT(cmd,) peer_lsa, remotefile, fd, port, blocksize);
452 if (ENABLE_FEATURE_CLEAN_UP)
454 if (result != EXIT_SUCCESS && !LONE_DASH(localfile) && CMD_GET(cmd)) {
460 #endif /* ENABLE_FEATURE_TFTP_GET || ENABLE_FEATURE_TFTP_PUT */