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
41 #define CMD_GET(cmd) 1
42 #define CMD_PUT(cmd) 0
43 #elif !ENABLE_FEATURE_TFTP_GET && ENABLE_FEATURE_TFTP_PUT
45 #define CMD_GET(cmd) 0
46 #define CMD_PUT(cmd) 1
48 #define USE_GETPUT(a) a
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) {
113 #if ENABLE_FEATURE_TFTP_GET && ENABLE_FEATURE_TFTP_PUT
116 len_and_sockaddr *peer_lsa,
117 const char *remotefile, const int localfd,
118 unsigned port, int tftp_bufsize)
125 USE_FEATURE_TFTP_BLOCKSIZE(smallint want_option_ack = 0;)
126 smallint finished = 0;
128 uint16_t block_nr = 1;
130 int timeout = TFTP_NUM_RETRIES;
134 len_and_sockaddr *const from = alloca(offsetof(len_and_sockaddr, sa) + peer_lsa->len);
136 /* Can't use RESERVE_CONFIG_BUFFER here since the allocation
137 * size varies meaning BUFFERS_GO_ON_STACK would fail */
138 /* We must keep the transmit and receive buffers seperate */
139 /* In case we rcv a garbage pkt and we need to rexmit the last pkt */
140 char *xbuf = xmalloc(tftp_bufsize += 4);
141 char *rbuf = xmalloc(tftp_bufsize);
143 port = org_port = htons(port);
145 socketfd = xsocket(peer_lsa->sa.sa_family, SOCK_DGRAM, 0);
153 /* add filename and mode */
154 /* fill in packet if the filename fits into xbuf */
155 len = strlen(remotefile) + 1;
156 if (2 + len + sizeof("octet") >= tftp_bufsize) {
157 bb_error_msg("remote filename is too long");
160 strcpy(cp, remotefile);
162 /* add "mode" part of the package */
164 cp += sizeof("octet");
166 #if ENABLE_FEATURE_TFTP_BLOCKSIZE
167 len = tftp_bufsize - 4; /* data block size */
168 if (len != TFTP_BLOCKSIZE_DEFAULT) {
169 /* rfc2348 says that 65464 is a max allowed value */
170 if ((&xbuf[tftp_bufsize - 1] - cp) < sizeof("blksize NNNNN")) {
171 bb_error_msg("remote filename is too long");
174 /* add "blksize", <nul>, blocksize */
175 strcpy(cp, "blksize");
176 cp += sizeof("blksize");
177 cp += snprintf(cp, 6, "%d", len) + 1;
181 /* First packet is built, so skip packet generation */
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 timeout = TFTP_NUM_RETRIES; /* re-initialize */
208 send_len = cp - xbuf;
209 /* nb: need to preserve send_len value in code below
210 * for potential resend! */
212 #if ENABLE_DEBUG_TFTP
213 fprintf(stderr, "sending %u bytes\n", send_len);
214 for (cp = xbuf; cp < &xbuf[send_len]; cp++)
215 fprintf(stderr, "%02x ", (unsigned char) *cp);
216 fprintf(stderr, "\n");
218 xsendto(socketfd, xbuf, send_len, &peer_lsa->sa, peer_lsa->len);
219 /* Was it final ACK? then exit */
220 if (finished && (opcode == TFTP_ACK))
225 tv.tv_sec = TFTP_TIMEOUT;
228 FD_SET(socketfd, &rfds);
229 switch (select(socketfd + 1, &rfds, NULL, NULL, &tv)) {
232 from->len = peer_lsa->len;
233 memset(&from->sa, 0, peer_lsa->len);
234 len = recvfrom(socketfd, rbuf, tftp_bufsize, 0,
235 &from->sa, &from->len);
237 bb_perror_msg("recvfrom");
240 from_port = get_nport(&from->sa);
241 if (port == org_port) {
242 /* Our first query went to port 69
243 * but reply will come from different one.
244 * Remember and use this new port */
246 set_nport(peer_lsa, from_port);
248 if (port != from_port)
254 bb_error_msg("last timeout");
257 bb_error_msg("last timeout" + 5);
258 goto send_again; /* resend last sent pkt */
260 bb_perror_msg("select");
263 } /* while we don't see recv packet with correct port# */
265 /* Process recv'ed packet */
267 opcode = ntohs( ((uint16_t*)rbuf)[0] );
268 recv_blk = ntohs( ((uint16_t*)rbuf)[1] );
270 #if ENABLE_DEBUG_TFTP
271 fprintf(stderr, "received %d bytes: %04x %04x\n", len, opcode, recv_blk);
274 if (opcode == TFTP_ERROR) {
275 static const char *const errcode_str[] = {
280 "illegal TFTP operation",
281 "unknown transfer id",
282 "file already exists",
285 enum { NUM_ERRCODE = sizeof(errcode_str) / sizeof(errcode_str[0]) };
287 const char *msg = "";
289 if (rbuf[4] != '\0') {
291 rbuf[tftp_bufsize - 1] = '\0';
292 } else if (recv_blk < NUM_ERRCODE) {
293 msg = errcode_str[recv_blk];
295 bb_error_msg("server error: (%u) %s", recv_blk, msg);
299 #if ENABLE_FEATURE_TFTP_BLOCKSIZE
300 if (want_option_ack) {
303 if (opcode == TFTP_OACK) {
304 /* server seems to support options */
307 res = tftp_option_get(&rbuf[2], len - 2, "blksize");
309 int blksize = xatoi_u(res);
310 if (!tftp_blocksize_check(blksize, tftp_bufsize - 4)) {
311 bb_error_msg("server proposes bad blksize %d, exiting", blksize);
312 // FIXME: must also send ERROR 8 to server...
315 #if ENABLE_DEBUG_TFTP
316 fprintf(stderr, "using blksize %u\n",
319 tftp_bufsize = blksize + 4;
320 block_nr = 0; // TODO: explain why???
324 * "An option not acknowledged by the server
325 * must be ignored by the client and server
326 * as if it were never requested." */
329 bb_error_msg("blksize is not supported by server"
330 " - reverting to 512");
331 tftp_bufsize = TFTP_BLOCKSIZE_DEFAULT + 4;
334 /* block_nr is already advanced to next block# we expect
335 * to get / block# we are about to send next time */
337 if (CMD_GET(cmd) && (opcode == TFTP_DATA)) {
338 if (recv_blk == block_nr) {
339 len = full_write(localfd, &rbuf[4], len - 4);
341 bb_perror_msg(bb_msg_write_error);
344 if (len != (tftp_bufsize - 4)) {
347 continue; /* send ACK */
349 if (recv_blk == (block_nr - 1)) {
350 /* Server lost our TFTP_ACK. Resend it */
356 if (CMD_PUT(cmd) && (opcode == TFTP_ACK)) {
357 /* did server ACK our last DATA pkt? */
358 if (recv_blk == (uint16_t) (block_nr - 1)) {
361 continue; /* send next block */
364 /* Awww... recv'd packet is not recognized! */
366 /* why recv_again? - rfc1123 says:
367 * "The sender (i.e., the side originating the DATA packets)
368 * must never resend the current DATA packet on receipt
369 * of a duplicate ACK".
370 * DATA pkts are resent ONLY on timeout.
371 * Thus "goto send_again" will ba a bad mistake above.
373 * http://en.wikipedia.org/wiki/Sorcerer's_Apprentice_Syndrome
377 if (ENABLE_FEATURE_CLEAN_UP) {
382 return finished == 0; /* returns 1 on failure */
385 int tftp_main(int argc, char **argv);
386 int tftp_main(int argc, char **argv)
388 len_and_sockaddr *peer_lsa;
389 const char *localfile = NULL;
390 const char *remotefile = NULL;
391 #if ENABLE_FEATURE_TFTP_BLOCKSIZE
392 const char *sblocksize = NULL;
399 int blocksize = TFTP_BLOCKSIZE_DEFAULT;
401 /* -p or -g is mandatory, and they are mutually exclusive */
402 opt_complementary = "" USE_FEATURE_TFTP_GET("g:") USE_FEATURE_TFTP_PUT("p:")
403 USE_GETPUT("?g--p:p--g");
405 USE_GETPUT(cmd =) getopt32(argc, argv,
406 USE_FEATURE_TFTP_GET("g") USE_FEATURE_TFTP_PUT("p")
407 "l:r:" USE_FEATURE_TFTP_BLOCKSIZE("b:"),
408 &localfile, &remotefile
409 USE_FEATURE_TFTP_BLOCKSIZE(, &sblocksize));
414 flags = O_WRONLY | O_CREAT | O_TRUNC;
416 #if ENABLE_FEATURE_TFTP_BLOCKSIZE
418 blocksize = xatoi_u(sblocksize);
419 if (!tftp_blocksize_check(blocksize, 0)) {
426 localfile = remotefile;
428 remotefile = localfile;
429 /* Error if filename or host is not known */
430 if (!remotefile || !argv[0])
433 if (LONE_DASH(localfile)) {
434 fd = CMD_GET(cmd) ? STDOUT_FILENO : STDIN_FILENO;
436 fd = xopen(localfile, flags);
439 port = bb_lookup_port(argv[1], "udp", 69);
440 peer_lsa = xhost2sockaddr(argv[0], port);
442 #if ENABLE_DEBUG_TFTP
443 fprintf(stderr, "using server \"%s\", "
444 "remotefile \"%s\", localfile \"%s\"\n",
445 xmalloc_sockaddr2dotted(&peer_lsa->sa, peer_lsa->len),
446 remotefile, localfile);
450 #if ENABLE_FEATURE_TFTP_GET && ENABLE_FEATURE_TFTP_PUT
453 peer_lsa, remotefile, fd, port, blocksize);
455 if (ENABLE_FEATURE_CLEAN_UP)
457 if (result != EXIT_SUCCESS && !LONE_DASH(localfile) && CMD_GET(cmd)) {
463 #endif /* ENABLE_FEATURE_TFTP_GET || ENABLE_FEATURE_TFTP_PUT */