1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (C) 2008 Edwin Groothuis. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/cdefs.h>
29 #include <sys/types.h>
30 #include <sys/param.h>
31 #include <sys/ioctl.h>
32 #include <sys/stat.h>
33 #include <sys/socket.h>
34
35 #include <netinet/in.h>
36 #include <arpa/tftp.h>
37
38 #include <errno.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <string.h>
42 #include <syslog.h>
43
44 #include "tftp-file.h"
45 #include "tftp-io.h"
46 #include "tftp-utils.h"
47 #include "tftp-options.h"
48 #include "tftp-transfer.h"
49
50 struct block_data {
51 off_t offset;
52 uint16_t block;
53 int size;
54 };
55
56 /*
57 * Send a file via the TFTP data session.
58 */
59 void
tftp_send(int peer,uint16_t * block,struct tftp_stats * ts)60 tftp_send(int peer, uint16_t *block, struct tftp_stats *ts)
61 {
62 struct tftphdr *rp;
63 int size, n_data, n_ack, sendtry, acktry;
64 u_int i, j;
65 uint16_t oldblock, windowblock;
66 char sendbuffer[MAXPKTSIZE];
67 char recvbuffer[MAXPKTSIZE];
68 struct block_data window[WINDOWSIZE_MAX];
69
70 rp = (struct tftphdr *)recvbuffer;
71 *block = 1;
72 ts->amount = 0;
73 windowblock = 0;
74 acktry = 0;
75 do {
76 read_block:
77 if (debug&DEBUG_SIMPLE)
78 tftp_log(LOG_DEBUG, "Sending block %d (window block %d)",
79 *block, windowblock);
80
81 window[windowblock].offset = tell_file();
82 window[windowblock].block = *block;
83 size = read_file(sendbuffer, segsize);
84 if (size < 0) {
85 tftp_log(LOG_ERR, "read_file returned %d", size);
86 send_error(peer, errno + 100);
87 goto abort;
88 }
89 window[windowblock].size = size;
90 windowblock++;
91
92 for (sendtry = 0; ; sendtry++) {
93 n_data = send_data(peer, *block, sendbuffer, size);
94 if (n_data == 0)
95 break;
96
97 if (sendtry == maxtimeouts) {
98 tftp_log(LOG_ERR,
99 "Cannot send DATA packet #%d, "
100 "giving up", *block);
101 return;
102 }
103 tftp_log(LOG_ERR,
104 "Cannot send DATA packet #%d, trying again",
105 *block);
106 }
107
108 /* Only check for ACK for last block in window. */
109 if (windowblock == windowsize || size != segsize) {
110 n_ack = receive_packet(peer, recvbuffer,
111 MAXPKTSIZE, NULL, timeoutpacket);
112 if (n_ack < 0) {
113 if (n_ack == RP_TIMEOUT) {
114 if (acktry == maxtimeouts) {
115 tftp_log(LOG_ERR,
116 "Timeout #%d send ACK %d "
117 "giving up", acktry, *block);
118 return;
119 }
120 tftp_log(LOG_WARNING,
121 "Timeout #%d on ACK %d",
122 acktry, *block);
123
124 acktry++;
125 ts->retries++;
126 if (seek_file(window[0].offset) != 0) {
127 tftp_log(LOG_ERR,
128 "seek_file failed: %s",
129 strerror(errno));
130 send_error(peer, errno + 100);
131 goto abort;
132 }
133 *block = window[0].block;
134 windowblock = 0;
135 goto read_block;
136 }
137
138 /* Either read failure or ERROR packet */
139 if (debug&DEBUG_SIMPLE)
140 tftp_log(LOG_ERR, "Aborting: %s",
141 rp_strerror(n_ack));
142 goto abort;
143 }
144 if (rp->th_opcode == ACK) {
145 /*
146 * Look for the ACKed block in our open
147 * window.
148 */
149 for (i = 0; i < windowblock; i++) {
150 if (rp->th_block == window[i].block)
151 break;
152 }
153
154 if (i == windowblock) {
155 /* Did not recognize ACK. */
156 if (debug&DEBUG_SIMPLE)
157 tftp_log(LOG_DEBUG,
158 "ACK %d out of window",
159 rp->th_block);
160
161 /* Re-synchronize with the other side */
162 (void) synchnet(peer);
163
164 /* Resend the current window. */
165 ts->retries++;
166 if (seek_file(window[0].offset) != 0) {
167 tftp_log(LOG_ERR,
168 "seek_file failed: %s",
169 strerror(errno));
170 send_error(peer, errno + 100);
171 goto abort;
172 }
173 *block = window[0].block;
174 windowblock = 0;
175 goto read_block;
176 }
177
178 /* ACKed at least some data. */
179 acktry = 0;
180 for (j = 0; j <= i; j++) {
181 if (debug&DEBUG_SIMPLE)
182 tftp_log(LOG_DEBUG,
183 "ACKed block %d",
184 window[j].block);
185 ts->blocks++;
186 ts->amount += window[j].size;
187 }
188
189 /*
190 * Partial ACK. Rewind state to first
191 * un-ACKed block.
192 */
193 if (i + 1 != windowblock) {
194 if (debug&DEBUG_SIMPLE)
195 tftp_log(LOG_DEBUG,
196 "Partial ACK");
197 if (seek_file(window[i + 1].offset) !=
198 0) {
199 tftp_log(LOG_ERR,
200 "seek_file failed: %s",
201 strerror(errno));
202 send_error(peer, errno + 100);
203 goto abort;
204 }
205 *block = window[i + 1].block;
206 windowblock = 0;
207 ts->retries++;
208 goto read_block;
209 }
210
211 windowblock = 0;
212 }
213
214 }
215 oldblock = *block;
216 (*block)++;
217 if (oldblock > *block) {
218 if (options[OPT_ROLLOVER].o_request == NULL) {
219 /*
220 * "rollover" option not specified in
221 * tftp client. Default to rolling block
222 * counter to 0.
223 */
224 *block = 0;
225 } else {
226 *block = atoi(options[OPT_ROLLOVER].o_request);
227 }
228
229 ts->rollovers++;
230 }
231 gettimeofday(&(ts->tstop), NULL);
232 } while (size == segsize);
233 abort:
234 return;
235 }
236
237 /*
238 * Receive a file via the TFTP data session.
239 *
240 * - It could be that the first block has already arrived while
241 * trying to figure out if we were receiving options or not. In
242 * that case it is passed to this function.
243 */
244 void
tftp_receive(int peer,uint16_t * block,struct tftp_stats * ts,struct tftphdr * firstblock,size_t fb_size)245 tftp_receive(int peer, uint16_t *block, struct tftp_stats *ts,
246 struct tftphdr *firstblock, size_t fb_size)
247 {
248 struct tftphdr *rp;
249 uint16_t oldblock, windowstart;
250 int n_data, n_ack, writesize, i, retry, windowblock;
251 char recvbuffer[MAXPKTSIZE];
252
253 ts->amount = 0;
254 windowblock = 0;
255
256 if (firstblock != NULL) {
257 writesize = write_file(firstblock->th_data, fb_size);
258 ts->amount += writesize;
259 ts->blocks++;
260 windowblock++;
261 if (windowsize == 1 || fb_size != segsize) {
262 for (i = 0; ; i++) {
263 n_ack = send_ack(peer, *block);
264 if (n_ack > 0) {
265 if (i == maxtimeouts) {
266 tftp_log(LOG_ERR,
267 "Cannot send ACK packet #%d, "
268 "giving up", *block);
269 return;
270 }
271 tftp_log(LOG_ERR,
272 "Cannot send ACK packet #%d, trying again",
273 *block);
274 continue;
275 }
276
277 break;
278 }
279 }
280
281 if (fb_size != segsize) {
282 write_close();
283 gettimeofday(&(ts->tstop), NULL);
284 return;
285 }
286 }
287
288 rp = (struct tftphdr *)recvbuffer;
289 do {
290 oldblock = *block;
291 (*block)++;
292 if (oldblock > *block) {
293 if (options[OPT_ROLLOVER].o_request == NULL) {
294 /*
295 * "rollover" option not specified in
296 * tftp client. Default to rolling block
297 * counter to 0.
298 */
299 *block = 0;
300 } else {
301 *block = atoi(options[OPT_ROLLOVER].o_request);
302 }
303
304 ts->rollovers++;
305 }
306
307 for (retry = 0; ; retry++) {
308 if (debug&DEBUG_SIMPLE)
309 tftp_log(LOG_DEBUG,
310 "Receiving DATA block %d (window block %d)",
311 *block, windowblock);
312
313 n_data = receive_packet(peer, recvbuffer,
314 MAXPKTSIZE, NULL, timeoutpacket);
315 if (n_data < 0) {
316 if (retry == maxtimeouts) {
317 tftp_log(LOG_ERR,
318 "Timeout #%d on DATA block %d, "
319 "giving up", retry, *block);
320 return;
321 }
322 if (n_data == RP_TIMEOUT) {
323 tftp_log(LOG_WARNING,
324 "Timeout #%d on DATA block %d",
325 retry, *block);
326 send_ack(peer, oldblock);
327 windowblock = 0;
328 continue;
329 }
330
331 /* Either read failure or ERROR packet */
332 if (debug&DEBUG_SIMPLE)
333 tftp_log(LOG_DEBUG, "Aborting: %s",
334 rp_strerror(n_data));
335 goto abort;
336 }
337 if (rp->th_opcode == DATA) {
338 ts->blocks++;
339
340 if (rp->th_block == *block)
341 break;
342
343 /*
344 * Ignore duplicate blocks within the
345 * window.
346 *
347 * This does not handle duplicate
348 * blocks during a rollover as
349 * gracefully, but that should still
350 * recover eventually.
351 */
352 if (*block > windowsize)
353 windowstart = *block - windowsize;
354 else
355 windowstart = 0;
356 if (rp->th_block > windowstart &&
357 rp->th_block < *block) {
358 if (debug&DEBUG_SIMPLE)
359 tftp_log(LOG_DEBUG,
360 "Ignoring duplicate DATA block %d",
361 rp->th_block);
362 windowblock++;
363 retry = 0;
364 continue;
365 }
366
367 tftp_log(LOG_WARNING,
368 "Expected DATA block %d, got block %d",
369 *block, rp->th_block);
370
371 /* Re-synchronize with the other side */
372 (void) synchnet(peer);
373
374 tftp_log(LOG_INFO, "Trying to sync");
375 *block = oldblock;
376 ts->retries++;
377 goto send_ack; /* rexmit */
378
379 } else {
380 tftp_log(LOG_WARNING,
381 "Expected DATA block, got %s block",
382 packettype(rp->th_opcode));
383 }
384 }
385
386 if (n_data > 0) {
387 writesize = write_file(rp->th_data, n_data);
388 ts->amount += writesize;
389 if (writesize <= 0) {
390 tftp_log(LOG_ERR,
391 "write_file returned %d", writesize);
392 if (writesize < 0)
393 send_error(peer, errno + 100);
394 else
395 send_error(peer, ENOSPACE);
396 goto abort;
397 }
398 }
399 if (n_data != segsize)
400 write_close();
401 windowblock++;
402
403 /* Only send ACKs for the last block in the window. */
404 if (windowblock < windowsize && n_data == segsize)
405 continue;
406 send_ack:
407 for (i = 0; ; i++) {
408 n_ack = send_ack(peer, *block);
409 if (n_ack > 0) {
410
411 if (i == maxtimeouts) {
412 tftp_log(LOG_ERR,
413 "Cannot send ACK packet #%d, "
414 "giving up", *block);
415 return;
416 }
417
418 tftp_log(LOG_ERR,
419 "Cannot send ACK packet #%d, trying again",
420 *block);
421 continue;
422 }
423
424 if (debug&DEBUG_SIMPLE)
425 tftp_log(LOG_DEBUG, "Sent ACK for %d", *block);
426 windowblock = 0;
427 break;
428 }
429 gettimeofday(&(ts->tstop), NULL);
430 } while (n_data == segsize);
431
432 /* Don't do late packet management for the client implementation */
433 if (acting_as_client)
434 return;
435
436 for (i = 0; ; i++) {
437 n_data = receive_packet(peer, (char *)rp, pktsize,
438 NULL, timeoutpacket);
439 if (n_data <= 0)
440 break;
441 if (n_data > 0 &&
442 rp->th_opcode == DATA && /* and got a data block */
443 *block == rp->th_block) /* then my last ack was lost */
444 send_ack(peer, *block); /* resend final ack */
445 }
446
447 abort:
448 return;
449 }
450