1/***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2021, Daniel Stenberg, <daniel@haxx.se>, et al.
9 *
10 * This software is licensed as described in the file COPYING, which
11 * you should have received as part of this distribution. The terms
12 * are also available at https://curl.se/docs/copyright.html.
13 *
14 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
15 * copies of the Software, and permit persons to whom the Software is
16 * furnished to do so, under the terms of the COPYING file.
17 *
18 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
19 * KIND, either express or implied.
20 *
21 ***************************************************************************/
22
23#include "curl_setup.h"
24
25#ifndef CURL_DISABLE_TFTP
26
27#ifdef HAVE_NETINET_IN_H
28#include <netinet/in.h>
29#endif
30#ifdef HAVE_NETDB_H
31#include <netdb.h>
32#endif
33#ifdef HAVE_ARPA_INET_H
34#include <arpa/inet.h>
35#endif
36#ifdef HAVE_NET_IF_H
37#include <net/if.h>
38#endif
39#ifdef HAVE_SYS_IOCTL_H
40#include <sys/ioctl.h>
41#endif
42
43#ifdef HAVE_SYS_PARAM_H
44#include <sys/param.h>
45#endif
46
47#include "urldata.h"
48#include <curl/curl.h>
49#include "transfer.h"
50#include "sendf.h"
51#include "tftp.h"
52#include "progress.h"
53#include "connect.h"
54#include "strerror.h"
55#include "sockaddr.h" /* required for Curl_sockaddr_storage */
56#include "multiif.h"
57#include "url.h"
58#include "strcase.h"
59#include "speedcheck.h"
60#include "select.h"
61#include "escape.h"
62
63/* The last 3 #include files should be in this order */
64#include "curl_printf.h"
65#include "curl_memory.h"
66#include "memdebug.h"
67
68/* RFC2348 allows the block size to be negotiated */
69#define TFTP_BLKSIZE_DEFAULT 512
70#define TFTP_BLKSIZE_MIN 8
71#define TFTP_BLKSIZE_MAX 65464
72#define TFTP_OPTION_BLKSIZE "blksize"
73
74/* from RFC2349: */
75#define TFTP_OPTION_TSIZE "tsize"
76#define TFTP_OPTION_INTERVAL "timeout"
77
78typedef enum {
79 TFTP_MODE_NETASCII = 0,
80 TFTP_MODE_OCTET
81} tftp_mode_t;
82
83typedef enum {
84 TFTP_STATE_START = 0,
85 TFTP_STATE_RX,
86 TFTP_STATE_TX,
87 TFTP_STATE_FIN
88} tftp_state_t;
89
90typedef enum {
91 TFTP_EVENT_NONE = -1,
92 TFTP_EVENT_INIT = 0,
93 TFTP_EVENT_RRQ = 1,
94 TFTP_EVENT_WRQ = 2,
95 TFTP_EVENT_DATA = 3,
96 TFTP_EVENT_ACK = 4,
97 TFTP_EVENT_ERROR = 5,
98 TFTP_EVENT_OACK = 6,
99 TFTP_EVENT_TIMEOUT
100} tftp_event_t;
101
102typedef enum {
103 TFTP_ERR_UNDEF = 0,
104 TFTP_ERR_NOTFOUND,
105 TFTP_ERR_PERM,
106 TFTP_ERR_DISKFULL,
107 TFTP_ERR_ILLEGAL,
108 TFTP_ERR_UNKNOWNID,
109 TFTP_ERR_EXISTS,
110 TFTP_ERR_NOSUCHUSER, /* This will never be triggered by this code */
111
112 /* The remaining error codes are internal to curl */
113 TFTP_ERR_NONE = -100,
114 TFTP_ERR_TIMEOUT,
115 TFTP_ERR_NORESPONSE
116} tftp_error_t;
117
118struct tftp_packet {
119 unsigned char *data;
120};
121
122struct tftp_state_data {
123 tftp_state_t state;
124 tftp_mode_t mode;
125 tftp_error_t error;
126 tftp_event_t event;
127 struct Curl_easy *data;
128 curl_socket_t sockfd;
129 int retries;
130 int retry_time;
131 int retry_max;
132 time_t rx_time;
133 struct Curl_sockaddr_storage local_addr;
134 struct Curl_sockaddr_storage remote_addr;
135 curl_socklen_t remote_addrlen;
136 int rbytes;
137 int sbytes;
138 int blksize;
139 int requested_blksize;
140 unsigned short block;
141 struct tftp_packet rpacket;
142 struct tftp_packet spacket;
143};
144
145
146/* Forward declarations */
147static CURLcode tftp_rx(struct tftp_state_data *state, tftp_event_t event);
148static CURLcode tftp_tx(struct tftp_state_data *state, tftp_event_t event);
149static CURLcode tftp_connect(struct Curl_easy *data, bool *done);
150static CURLcode tftp_disconnect(struct Curl_easy *data,
151 struct connectdata *conn,
152 bool dead_connection);
153static CURLcode tftp_do(struct Curl_easy *data, bool *done);
154static CURLcode tftp_done(struct Curl_easy *data,
155 CURLcode, bool premature);
156static CURLcode tftp_setup_connection(struct Curl_easy *data,
157 struct connectdata *conn);
158static CURLcode tftp_multi_statemach(struct Curl_easy *data, bool *done);
159static CURLcode tftp_doing(struct Curl_easy *data, bool *dophase_done);
160static int tftp_getsock(struct Curl_easy *data, struct connectdata *conn,
161 curl_socket_t *socks);
162static CURLcode tftp_translate_code(tftp_error_t error);
163
164
165/*
166 * TFTP protocol handler.
167 */
168
169const struct Curl_handler Curl_handler_tftp = {
170 "TFTP", /* scheme */
171 tftp_setup_connection, /* setup_connection */
172 tftp_do, /* do_it */
173 tftp_done, /* done */
174 ZERO_NULL, /* do_more */
175 tftp_connect, /* connect_it */
176 tftp_multi_statemach, /* connecting */
177 tftp_doing, /* doing */
178 tftp_getsock, /* proto_getsock */
179 tftp_getsock, /* doing_getsock */
180 ZERO_NULL, /* domore_getsock */
181 ZERO_NULL, /* perform_getsock */
182 tftp_disconnect, /* disconnect */
183 ZERO_NULL, /* readwrite */
184 ZERO_NULL, /* connection_check */
185 ZERO_NULL, /* attach connection */
186 PORT_TFTP, /* defport */
187 CURLPROTO_TFTP, /* protocol */
188 CURLPROTO_TFTP, /* family */
189 PROTOPT_NONE | PROTOPT_NOURLQUERY /* flags */
190};
191
192/**********************************************************
193 *
194 * tftp_set_timeouts -
195 *
196 * Set timeouts based on state machine state.
197 * Use user provided connect timeouts until DATA or ACK
198 * packet is received, then use user-provided transfer timeouts
199 *
200 *
201 **********************************************************/
202static CURLcode tftp_set_timeouts(struct tftp_state_data *state)
203{
204 time_t maxtime, timeout;
205 timediff_t timeout_ms;
206 bool start = (state->state == TFTP_STATE_START) ? TRUE : FALSE;
207
208 /* Compute drop-dead time */
209 timeout_ms = Curl_timeleft(state->data, NULL, start);
210
211 if(timeout_ms < 0) {
212 /* time-out, bail out, go home */
213 failf(state->data, "Connection time-out");
214 return CURLE_OPERATION_TIMEDOUT;
215 }
216
217 if(timeout_ms > 0)
218 maxtime = (time_t)(timeout_ms + 500) / 1000;
219 else
220 maxtime = 3600; /* use for calculating block timeouts */
221
222 /* Set per-block timeout to total */
223 timeout = maxtime;
224
225 /* Average reposting an ACK after 5 seconds */
226 state->retry_max = (int)timeout/5;
227
228 /* But bound the total number */
229 if(state->retry_max<3)
230 state->retry_max = 3;
231
232 if(state->retry_max>50)
233 state->retry_max = 50;
234
235 /* Compute the re-ACK interval to suit the timeout */
236 state->retry_time = (int)(timeout/state->retry_max);
237 if(state->retry_time<1)
238 state->retry_time = 1;
239
240 infof(state->data,
241 "set timeouts for state %d; Total % " CURL_FORMAT_CURL_OFF_T
242 ", retry %d maxtry %d",
243 (int)state->state, timeout_ms, state->retry_time, state->retry_max);
244
245 /* init RX time */
246 time(&state->rx_time);
247
248 return CURLE_OK;
249}
250
251/**********************************************************
252 *
253 * tftp_set_send_first
254 *
255 * Event handler for the START state
256 *
257 **********************************************************/
258
259static void setpacketevent(struct tftp_packet *packet, unsigned short num)
260{
261 packet->data[0] = (unsigned char)(num >> 8);
262 packet->data[1] = (unsigned char)(num & 0xff);
263}
264
265
266static void setpacketblock(struct tftp_packet *packet, unsigned short num)
267{
268 packet->data[2] = (unsigned char)(num >> 8);
269 packet->data[3] = (unsigned char)(num & 0xff);
270}
271
272static unsigned short getrpacketevent(const struct tftp_packet *packet)
273{
274 return (unsigned short)((packet->data[0] << 8) | packet->data[1]);
275}
276
277static unsigned short getrpacketblock(const struct tftp_packet *packet)
278{
279 return (unsigned short)((packet->data[2] << 8) | packet->data[3]);
280}
281
282static size_t tftp_strnlen(const char *string, size_t maxlen)
283{
284 const char *end = memchr(string, '\0', maxlen);
285 return end ? (size_t) (end - string) : maxlen;
286}
287
288static const char *tftp_option_get(const char *buf, size_t len,
289 const char **option, const char **value)
290{
291 size_t loc;
292
293 loc = tftp_strnlen(buf, len);
294 loc++; /* NULL term */
295
296 if(loc >= len)
297 return NULL;
298 *option = buf;
299
300 loc += tftp_strnlen(buf + loc, len-loc);
301 loc++; /* NULL term */
302
303 if(loc > len)
304 return NULL;
305 *value = &buf[strlen(*option) + 1];
306
307 return &buf[loc];
308}
309
310static CURLcode tftp_parse_option_ack(struct tftp_state_data *state,
311 const char *ptr, int len)
312{
313 const char *tmp = ptr;
314 struct Curl_easy *data = state->data;
315
316 /* if OACK doesn't contain blksize option, the default (512) must be used */
317 state->blksize = TFTP_BLKSIZE_DEFAULT;
318
319 while(tmp < ptr + len) {
320 const char *option, *value;
321
322 tmp = tftp_option_get(tmp, ptr + len - tmp, &option, &value);
323 if(!tmp) {
324 failf(data, "Malformed ACK packet, rejecting");
325 return CURLE_TFTP_ILLEGAL;
326 }
327
328 infof(data, "got option=(%s) value=(%s)", option, value);
329
330 if(checkprefix(option, TFTP_OPTION_BLKSIZE)) {
331 long blksize;
332
333 blksize = strtol(value, NULL, 10);
334
335 if(!blksize) {
336 failf(data, "invalid blocksize value in OACK packet");
337 return CURLE_TFTP_ILLEGAL;
338 }
339 if(blksize > TFTP_BLKSIZE_MAX) {
340 failf(data, "%s (%d)", "blksize is larger than max supported",
341 TFTP_BLKSIZE_MAX);
342 return CURLE_TFTP_ILLEGAL;
343 }
344 else if(blksize < TFTP_BLKSIZE_MIN) {
345 failf(data, "%s (%d)", "blksize is smaller than min supported",
346 TFTP_BLKSIZE_MIN);
347 return CURLE_TFTP_ILLEGAL;
348 }
349 else if(blksize > state->requested_blksize) {
350 /* could realloc pkt buffers here, but the spec doesn't call out
351 * support for the server requesting a bigger blksize than the client
352 * requests */
353 failf(data, "%s (%ld)",
354 "server requested blksize larger than allocated", blksize);
355 return CURLE_TFTP_ILLEGAL;
356 }
357
358 state->blksize = (int)blksize;
359 infof(data, "%s (%d) %s (%d)", "blksize parsed from OACK",
360 state->blksize, "requested", state->requested_blksize);
361 }
362 else if(checkprefix(option, TFTP_OPTION_TSIZE)) {
363 long tsize = 0;
364
365 tsize = strtol(value, NULL, 10);
366 infof(data, "%s (%ld)", "tsize parsed from OACK", tsize);
367
368 /* tsize should be ignored on upload: Who cares about the size of the
369 remote file? */
370 if(!data->set.upload) {
371 if(!tsize) {
372 failf(data, "invalid tsize -:%s:- value in OACK packet", value);
373 return CURLE_TFTP_ILLEGAL;
374 }
375 Curl_pgrsSetDownloadSize(data, tsize);
376 }
377 }
378 }
379
380 return CURLE_OK;
381}
382
383static CURLcode tftp_option_add(struct tftp_state_data *state, size_t *csize,
384 char *buf, const char *option)
385{
386 if(( strlen(option) + *csize + 1) > (size_t)state->blksize)
387 return CURLE_TFTP_ILLEGAL;
388 strcpy(buf, option);
389 *csize += strlen(option) + 1;
390 return CURLE_OK;
391}
392
393static CURLcode tftp_connect_for_tx(struct tftp_state_data *state,
394 tftp_event_t event)
395{
396 CURLcode result;
397#ifndef CURL_DISABLE_VERBOSE_STRINGS
398 struct Curl_easy *data = state->data;
399
400 infof(data, "%s", "Connected for transmit");
401#endif
402 state->state = TFTP_STATE_TX;
403 result = tftp_set_timeouts(state);
404 if(result)
405 return result;
406 return tftp_tx(state, event);
407}
408
409static CURLcode tftp_connect_for_rx(struct tftp_state_data *state,
410 tftp_event_t event)
411{
412 CURLcode result;
413#ifndef CURL_DISABLE_VERBOSE_STRINGS
414 struct Curl_easy *data = state->data;
415
416 infof(data, "%s", "Connected for receive");
417#endif
418 state->state = TFTP_STATE_RX;
419 result = tftp_set_timeouts(state);
420 if(result)
421 return result;
422 return tftp_rx(state, event);
423}
424
425static CURLcode tftp_send_first(struct tftp_state_data *state,
426 tftp_event_t event)
427{
428 size_t sbytes;
429 ssize_t senddata;
430 const char *mode = "octet";
431 char *filename;
432 struct Curl_easy *data = state->data;
433 CURLcode result = CURLE_OK;
434
435 /* Set ascii mode if -B flag was used */
436 if(data->state.prefer_ascii)
437 mode = "netascii";
438
439 switch(event) {
440
441 case TFTP_EVENT_INIT: /* Send the first packet out */
442 case TFTP_EVENT_TIMEOUT: /* Resend the first packet out */
443 /* Increment the retry counter, quit if over the limit */
444 state->retries++;
445 if(state->retries>state->retry_max) {
446 state->error = TFTP_ERR_NORESPONSE;
447 state->state = TFTP_STATE_FIN;
448 return result;
449 }
450
451 if(data->set.upload) {
452 /* If we are uploading, send an WRQ */
453 setpacketevent(&state->spacket, TFTP_EVENT_WRQ);
454 state->data->req.upload_fromhere =
455 (char *)state->spacket.data + 4;
456 if(data->state.infilesize != -1)
457 Curl_pgrsSetUploadSize(data, data->state.infilesize);
458 }
459 else {
460 /* If we are downloading, send an RRQ */
461 setpacketevent(&state->spacket, TFTP_EVENT_RRQ);
462 }
463 /* As RFC3617 describes the separator slash is not actually part of the
464 file name so we skip the always-present first letter of the path
465 string. */
466 result = Curl_urldecode(data, &state->data->state.up.path[1], 0,
467 &filename, NULL, REJECT_ZERO);
468 if(result)
469 return result;
470
471 if(strlen(filename) > (state->blksize - strlen(mode) - 4)) {
472 failf(data, "TFTP file name too long");
473 free(filename);
474 return CURLE_TFTP_ILLEGAL; /* too long file name field */
475 }
476
477 msnprintf((char *)state->spacket.data + 2,
478 state->blksize,
479 "%s%c%s%c", filename, '\0', mode, '\0');
480 sbytes = 4 + strlen(filename) + strlen(mode);
481
482 /* optional addition of TFTP options */
483 if(!data->set.tftp_no_options) {
484 char buf[64];
485 /* add tsize option */
486 if(data->set.upload && (data->state.infilesize != -1))
487 msnprintf(buf, sizeof(buf), "%" CURL_FORMAT_CURL_OFF_T,
488 data->state.infilesize);
489 else
490 strcpy(buf, "0"); /* the destination is large enough */
491
492 result = tftp_option_add(state, &sbytes,
493 (char *)state->spacket.data + sbytes,
494 TFTP_OPTION_TSIZE);
495 if(result == CURLE_OK)
496 result = tftp_option_add(state, &sbytes,
497 (char *)state->spacket.data + sbytes, buf);
498
499 /* add blksize option */
500 msnprintf(buf, sizeof(buf), "%d", state->requested_blksize);
501 if(result == CURLE_OK)
502 result = tftp_option_add(state, &sbytes,
503 (char *)state->spacket.data + sbytes,
504 TFTP_OPTION_BLKSIZE);
505 if(result == CURLE_OK)
506 result = tftp_option_add(state, &sbytes,
507 (char *)state->spacket.data + sbytes, buf);
508
509 /* add timeout option */
510 msnprintf(buf, sizeof(buf), "%d", state->retry_time);
511 if(result == CURLE_OK)
512 result = tftp_option_add(state, &sbytes,
513 (char *)state->spacket.data + sbytes,
514 TFTP_OPTION_INTERVAL);
515 if(result == CURLE_OK)
516 result = tftp_option_add(state, &sbytes,
517 (char *)state->spacket.data + sbytes, buf);
518
519 if(result != CURLE_OK) {
520 failf(data, "TFTP buffer too small for options");
521 free(filename);
522 return CURLE_TFTP_ILLEGAL;
523 }
524 }
525
526 /* the typecase for the 3rd argument is mostly for systems that do
527 not have a size_t argument, like older unixes that want an 'int' */
528 senddata = sendto(state->sockfd, (void *)state->spacket.data,
529 (SEND_TYPE_ARG3)sbytes, 0,
530 data->conn->ip_addr->ai_addr,
531 data->conn->ip_addr->ai_addrlen);
532 if(senddata != (ssize_t)sbytes) {
533 char buffer[STRERROR_LEN];
534 failf(data, "%s", Curl_strerror(SOCKERRNO, buffer, sizeof(buffer)));
535 }
536 free(filename);
537 break;
538
539 case TFTP_EVENT_OACK:
540 if(data->set.upload) {
541 result = tftp_connect_for_tx(state, event);
542 }
543 else {
544 result = tftp_connect_for_rx(state, event);
545 }
546 break;
547
548 case TFTP_EVENT_ACK: /* Connected for transmit */
549 result = tftp_connect_for_tx(state, event);
550 break;
551
552 case TFTP_EVENT_DATA: /* Connected for receive */
553 result = tftp_connect_for_rx(state, event);
554 break;
555
556 case TFTP_EVENT_ERROR:
557 state->state = TFTP_STATE_FIN;
558 break;
559
560 default:
561 failf(state->data, "tftp_send_first: internal error");
562 break;
563 }
564
565 return result;
566}
567
568/* the next blocknum is x + 1 but it needs to wrap at an unsigned 16bit
569 boundary */
570#define NEXT_BLOCKNUM(x) (((x) + 1)&0xffff)
571
572/**********************************************************
573 *
574 * tftp_rx
575 *
576 * Event handler for the RX state
577 *
578 **********************************************************/
579static CURLcode tftp_rx(struct tftp_state_data *state,
580 tftp_event_t event)
581{
582 ssize_t sbytes;
583 int rblock;
584 struct Curl_easy *data = state->data;
585 char buffer[STRERROR_LEN];
586
587 switch(event) {
588
589 case TFTP_EVENT_DATA:
590 /* Is this the block we expect? */
591 rblock = getrpacketblock(&state->rpacket);
592 if(NEXT_BLOCKNUM(state->block) == rblock) {
593 /* This is the expected block. Reset counters and ACK it. */
594 state->retries = 0;
595 }
596 else if(state->block == rblock) {
597 /* This is the last recently received block again. Log it and ACK it
598 again. */
599 infof(data, "Received last DATA packet block %d again.", rblock);
600 }
601 else {
602 /* totally unexpected, just log it */
603 infof(data,
604 "Received unexpected DATA packet block %d, expecting block %d",
605 rblock, NEXT_BLOCKNUM(state->block));
606 break;
607 }
608
609 /* ACK this block. */
610 state->block = (unsigned short)rblock;
611 setpacketevent(&state->spacket, TFTP_EVENT_ACK);
612 setpacketblock(&state->spacket, state->block);
613 sbytes = sendto(state->sockfd, (void *)state->spacket.data,
614 4, SEND_4TH_ARG,
615 (struct sockaddr *)&state->remote_addr,
616 state->remote_addrlen);
617 if(sbytes < 0) {
618 failf(data, "%s", Curl_strerror(SOCKERRNO, buffer, sizeof(buffer)));
619 return CURLE_SEND_ERROR;
620 }
621
622 /* Check if completed (That is, a less than full packet is received) */
623 if(state->rbytes < (ssize_t)state->blksize + 4) {
624 state->state = TFTP_STATE_FIN;
625 }
626 else {
627 state->state = TFTP_STATE_RX;
628 }
629 time(&state->rx_time);
630 break;
631
632 case TFTP_EVENT_OACK:
633 /* ACK option acknowledgement so we can move on to data */
634 state->block = 0;
635 state->retries = 0;
636 setpacketevent(&state->spacket, TFTP_EVENT_ACK);
637 setpacketblock(&state->spacket, state->block);
638 sbytes = sendto(state->sockfd, (void *)state->spacket.data,
639 4, SEND_4TH_ARG,
640 (struct sockaddr *)&state->remote_addr,
641 state->remote_addrlen);
642 if(sbytes < 0) {
643 failf(data, "%s", Curl_strerror(SOCKERRNO, buffer, sizeof(buffer)));
644 return CURLE_SEND_ERROR;
645 }
646
647 /* we're ready to RX data */
648 state->state = TFTP_STATE_RX;
649 time(&state->rx_time);
650 break;
651
652 case TFTP_EVENT_TIMEOUT:
653 /* Increment the retry count and fail if over the limit */
654 state->retries++;
655 infof(data,
656 "Timeout waiting for block %d ACK. Retries = %d",
657 NEXT_BLOCKNUM(state->block), state->retries);
658 if(state->retries > state->retry_max) {
659 state->error = TFTP_ERR_TIMEOUT;
660 state->state = TFTP_STATE_FIN;
661 }
662 else {
663 /* Resend the previous ACK */
664 sbytes = sendto(state->sockfd, (void *)state->spacket.data,
665 4, SEND_4TH_ARG,
666 (struct sockaddr *)&state->remote_addr,
667 state->remote_addrlen);
668 if(sbytes<0) {
669 failf(data, "%s", Curl_strerror(SOCKERRNO, buffer, sizeof(buffer)));
670 return CURLE_SEND_ERROR;
671 }
672 }
673 break;
674
675 case TFTP_EVENT_ERROR:
676 setpacketevent(&state->spacket, TFTP_EVENT_ERROR);
677 setpacketblock(&state->spacket, state->block);
678 (void)sendto(state->sockfd, (void *)state->spacket.data,
679 4, SEND_4TH_ARG,
680 (struct sockaddr *)&state->remote_addr,
681 state->remote_addrlen);
682 /* don't bother with the return code, but if the socket is still up we
683 * should be a good TFTP client and let the server know we're done */
684 state->state = TFTP_STATE_FIN;
685 break;
686
687 default:
688 failf(data, "%s", "tftp_rx: internal error");
689 return CURLE_TFTP_ILLEGAL; /* not really the perfect return code for
690 this */
691 }
692 return CURLE_OK;
693}
694
695/**********************************************************
696 *
697 * tftp_tx
698 *
699 * Event handler for the TX state
700 *
701 **********************************************************/
702static CURLcode tftp_tx(struct tftp_state_data *state, tftp_event_t event)
703{
704 struct Curl_easy *data = state->data;
705 ssize_t sbytes;
706 CURLcode result = CURLE_OK;
707 struct SingleRequest *k = &data->req;
708 size_t cb; /* Bytes currently read */
709 char buffer[STRERROR_LEN];
710
711 switch(event) {
712
713 case TFTP_EVENT_ACK:
714 case TFTP_EVENT_OACK:
715 if(event == TFTP_EVENT_ACK) {
716 /* Ack the packet */
717 int rblock = getrpacketblock(&state->rpacket);
718
719 if(rblock != state->block &&
720 /* There's a bug in tftpd-hpa that causes it to send us an ack for
721 * 65535 when the block number wraps to 0. So when we're expecting
722 * 0, also accept 65535. See
723 * https://www.syslinux.org/archives/2010-September/015612.html
724 * */
725 !(state->block == 0 && rblock == 65535)) {
726 /* This isn't the expected block. Log it and up the retry counter */
727 infof(data, "Received ACK for block %d, expecting %d",
728 rblock, state->block);
729 state->retries++;
730 /* Bail out if over the maximum */
731 if(state->retries>state->retry_max) {
732 failf(data, "tftp_tx: giving up waiting for block %d ack",
733 state->block);
734 result = CURLE_SEND_ERROR;
735 }
736 else {
737 /* Re-send the data packet */
738 sbytes = sendto(state->sockfd, (void *)state->spacket.data,
739 4 + state->sbytes, SEND_4TH_ARG,
740 (struct sockaddr *)&state->remote_addr,
741 state->remote_addrlen);
742 /* Check all sbytes were sent */
743 if(sbytes<0) {
744 failf(data, "%s", Curl_strerror(SOCKERRNO,
745 buffer, sizeof(buffer)));
746 result = CURLE_SEND_ERROR;
747 }
748 }
749
750 return result;
751 }
752 /* This is the expected packet. Reset the counters and send the next
753 block */
754 time(&state->rx_time);
755 state->block++;
756 }
757 else
758 state->block = 1; /* first data block is 1 when using OACK */
759
760 state->retries = 0;
761 setpacketevent(&state->spacket, TFTP_EVENT_DATA);
762 setpacketblock(&state->spacket, state->block);
763 if(state->block > 1 && state->sbytes < state->blksize) {
764 state->state = TFTP_STATE_FIN;
765 return CURLE_OK;
766 }
767
768 /* TFTP considers data block size < 512 bytes as an end of session. So
769 * in some cases we must wait for additional data to build full (512 bytes)
770 * data block.
771 * */
772 state->sbytes = 0;
773 state->data->req.upload_fromhere = (char *)state->spacket.data + 4;
774 do {
775 result = Curl_fillreadbuffer(data, state->blksize - state->sbytes, &cb);
776 if(result)
777 return result;
778 state->sbytes += (int)cb;
779 state->data->req.upload_fromhere += cb;
780 } while(state->sbytes < state->blksize && cb);
781
782 sbytes = sendto(state->sockfd, (void *) state->spacket.data,
783 4 + state->sbytes, SEND_4TH_ARG,
784 (struct sockaddr *)&state->remote_addr,
785 state->remote_addrlen);
786 /* Check all sbytes were sent */
787 if(sbytes<0) {
788 failf(data, "%s", Curl_strerror(SOCKERRNO, buffer, sizeof(buffer)));
789 return CURLE_SEND_ERROR;
790 }
791 /* Update the progress meter */
792 k->writebytecount += state->sbytes;
793 Curl_pgrsSetUploadCounter(data, k->writebytecount);
794 break;
795
796 case TFTP_EVENT_TIMEOUT:
797 /* Increment the retry counter and log the timeout */
798 state->retries++;
799 infof(data, "Timeout waiting for block %d ACK. "
800 " Retries = %d", NEXT_BLOCKNUM(state->block), state->retries);
801 /* Decide if we've had enough */
802 if(state->retries > state->retry_max) {
803 state->error = TFTP_ERR_TIMEOUT;
804 state->state = TFTP_STATE_FIN;
805 }
806 else {
807 /* Re-send the data packet */
808 sbytes = sendto(state->sockfd, (void *)state->spacket.data,
809 4 + state->sbytes, SEND_4TH_ARG,
810 (struct sockaddr *)&state->remote_addr,
811 state->remote_addrlen);
812 /* Check all sbytes were sent */
813 if(sbytes<0) {
814 failf(data, "%s", Curl_strerror(SOCKERRNO, buffer, sizeof(buffer)));
815 return CURLE_SEND_ERROR;
816 }
817 /* since this was a re-send, we remain at the still byte position */
818 Curl_pgrsSetUploadCounter(data, k->writebytecount);
819 }
820 break;
821
822 case TFTP_EVENT_ERROR:
823 state->state = TFTP_STATE_FIN;
824 setpacketevent(&state->spacket, TFTP_EVENT_ERROR);
825 setpacketblock(&state->spacket, state->block);
826 (void)sendto(state->sockfd, (void *)state->spacket.data, 4, SEND_4TH_ARG,
827 (struct sockaddr *)&state->remote_addr,
828 state->remote_addrlen);
829 /* don't bother with the return code, but if the socket is still up we
830 * should be a good TFTP client and let the server know we're done */
831 state->state = TFTP_STATE_FIN;
832 break;
833
834 default:
835 failf(data, "tftp_tx: internal error, event: %i", (int)(event));
836 break;
837 }
838
839 return result;
840}
841
842/**********************************************************
843 *
844 * tftp_translate_code
845 *
846 * Translate internal error codes to CURL error codes
847 *
848 **********************************************************/
849static CURLcode tftp_translate_code(tftp_error_t error)
850{
851 CURLcode result = CURLE_OK;
852
853 if(error != TFTP_ERR_NONE) {
854 switch(error) {
855 case TFTP_ERR_NOTFOUND:
856 result = CURLE_TFTP_NOTFOUND;
857 break;
858 case TFTP_ERR_PERM:
859 result = CURLE_TFTP_PERM;
860 break;
861 case TFTP_ERR_DISKFULL:
862 result = CURLE_REMOTE_DISK_FULL;
863 break;
864 case TFTP_ERR_UNDEF:
865 case TFTP_ERR_ILLEGAL:
866 result = CURLE_TFTP_ILLEGAL;
867 break;
868 case TFTP_ERR_UNKNOWNID:
869 result = CURLE_TFTP_UNKNOWNID;
870 break;
871 case TFTP_ERR_EXISTS:
872 result = CURLE_REMOTE_FILE_EXISTS;
873 break;
874 case TFTP_ERR_NOSUCHUSER:
875 result = CURLE_TFTP_NOSUCHUSER;
876 break;
877 case TFTP_ERR_TIMEOUT:
878 result = CURLE_OPERATION_TIMEDOUT;
879 break;
880 case TFTP_ERR_NORESPONSE:
881 result = CURLE_COULDNT_CONNECT;
882 break;
883 default:
884 result = CURLE_ABORTED_BY_CALLBACK;
885 break;
886 }
887 }
888 else
889 result = CURLE_OK;
890
891 return result;
892}
893
894/**********************************************************
895 *
896 * tftp_state_machine
897 *
898 * The tftp state machine event dispatcher
899 *
900 **********************************************************/
901static CURLcode tftp_state_machine(struct tftp_state_data *state,
902 tftp_event_t event)
903{
904 CURLcode result = CURLE_OK;
905 struct Curl_easy *data = state->data;
906
907 switch(state->state) {
908 case TFTP_STATE_START:
909 DEBUGF(infof(data, "TFTP_STATE_START"));
910 result = tftp_send_first(state, event);
911 break;
912 case TFTP_STATE_RX:
913 DEBUGF(infof(data, "TFTP_STATE_RX"));
914 result = tftp_rx(state, event);
915 break;
916 case TFTP_STATE_TX:
917 DEBUGF(infof(data, "TFTP_STATE_TX"));
918 result = tftp_tx(state, event);
919 break;
920 case TFTP_STATE_FIN:
921 infof(data, "%s", "TFTP finished");
922 break;
923 default:
924 DEBUGF(infof(data, "STATE: %d", state->state));
925 failf(data, "%s", "Internal state machine error");
926 result = CURLE_TFTP_ILLEGAL;
927 break;
928 }
929
930 return result;
931}
932
933/**********************************************************
934 *
935 * tftp_disconnect
936 *
937 * The disconnect callback
938 *
939 **********************************************************/
940static CURLcode tftp_disconnect(struct Curl_easy *data,
941 struct connectdata *conn, bool dead_connection)
942{
943 struct tftp_state_data *state = conn->proto.tftpc;
944 (void) data;
945 (void) dead_connection;
946
947 /* done, free dynamically allocated pkt buffers */
948 if(state) {
949 Curl_safefree(state->rpacket.data);
950 Curl_safefree(state->spacket.data);
951 free(state);
952 }
953
954 return CURLE_OK;
955}
956
957/**********************************************************
958 *
959 * tftp_connect
960 *
961 * The connect callback
962 *
963 **********************************************************/
964static CURLcode tftp_connect(struct Curl_easy *data, bool *done)
965{
966 struct tftp_state_data *state;
967 int blksize;
968 int need_blksize;
969 struct connectdata *conn = data->conn;
970
971 blksize = TFTP_BLKSIZE_DEFAULT;
972
973 state = conn->proto.tftpc = calloc(1, sizeof(struct tftp_state_data));
974 if(!state)
975 return CURLE_OUT_OF_MEMORY;
976
977 /* alloc pkt buffers based on specified blksize */
978 if(data->set.tftp_blksize) {
979 blksize = (int)data->set.tftp_blksize;
980 if(blksize > TFTP_BLKSIZE_MAX || blksize < TFTP_BLKSIZE_MIN)
981 return CURLE_TFTP_ILLEGAL;
982 }
983
984 need_blksize = blksize;
985 /* default size is the fallback when no OACK is received */
986 if(need_blksize < TFTP_BLKSIZE_DEFAULT)
987 need_blksize = TFTP_BLKSIZE_DEFAULT;
988
989 if(!state->rpacket.data) {
990 state->rpacket.data = calloc(1, need_blksize + 2 + 2);
991
992 if(!state->rpacket.data)
993 return CURLE_OUT_OF_MEMORY;
994 }
995
996 if(!state->spacket.data) {
997 state->spacket.data = calloc(1, need_blksize + 2 + 2);
998
999 if(!state->spacket.data)
1000 return CURLE_OUT_OF_MEMORY;
1001 }
1002
1003 /* we don't keep TFTP connections up basically because there's none or very
1004 * little gain for UDP */
1005 connclose(conn, "TFTP");
1006
1007 state->data = data;
1008 state->sockfd = conn->sock[FIRSTSOCKET];
1009 state->state = TFTP_STATE_START;
1010 state->error = TFTP_ERR_NONE;
1011 state->blksize = TFTP_BLKSIZE_DEFAULT; /* Unless updated by OACK response */
1012 state->requested_blksize = blksize;
1013
1014 ((struct sockaddr *)&state->local_addr)->sa_family =
1015 (CURL_SA_FAMILY_T)(conn->ip_addr->ai_family);
1016
1017 tftp_set_timeouts(state);
1018
1019 if(!conn->bits.bound) {
1020 /* If not already bound, bind to any interface, random UDP port. If it is
1021 * reused or a custom local port was desired, this has already been done!
1022 *
1023 * We once used the size of the local_addr struct as the third argument
1024 * for bind() to better work with IPv6 or whatever size the struct could
1025 * have, but we learned that at least Tru64, AIX and IRIX *requires* the
1026 * size of that argument to match the exact size of a 'sockaddr_in' struct
1027 * when running IPv4-only.
1028 *
1029 * Therefore we use the size from the address we connected to, which we
1030 * assume uses the same IP version and thus hopefully this works for both
1031 * IPv4 and IPv6...
1032 */
1033 int rc = bind(state->sockfd, (struct sockaddr *)&state->local_addr,
1034 conn->ip_addr->ai_addrlen);
1035 if(rc) {
1036 char buffer[STRERROR_LEN];
1037 failf(data, "bind() failed; %s",
1038 Curl_strerror(SOCKERRNO, buffer, sizeof(buffer)));
1039 return CURLE_COULDNT_CONNECT;
1040 }
1041 conn->bits.bound = TRUE;
1042 }
1043
1044 Curl_pgrsStartNow(data);
1045
1046 *done = TRUE;
1047
1048 return CURLE_OK;
1049}
1050
1051/**********************************************************
1052 *
1053 * tftp_done
1054 *
1055 * The done callback
1056 *
1057 **********************************************************/
1058static CURLcode tftp_done(struct Curl_easy *data, CURLcode status,
1059 bool premature)
1060{
1061 CURLcode result = CURLE_OK;
1062 struct connectdata *conn = data->conn;
1063 struct tftp_state_data *state = conn->proto.tftpc;
1064
1065 (void)status; /* unused */
1066 (void)premature; /* not used */
1067
1068 if(Curl_pgrsDone(data))
1069 return CURLE_ABORTED_BY_CALLBACK;
1070
1071 /* If we have encountered an error */
1072 if(state)
1073 result = tftp_translate_code(state->error);
1074
1075 return result;
1076}
1077
1078/**********************************************************
1079 *
1080 * tftp_getsock
1081 *
1082 * The getsock callback
1083 *
1084 **********************************************************/
1085static int tftp_getsock(struct Curl_easy *data,
1086 struct connectdata *conn, curl_socket_t *socks)
1087{
1088 (void)data;
1089 socks[0] = conn->sock[FIRSTSOCKET];
1090 return GETSOCK_READSOCK(0);
1091}
1092
1093/**********************************************************
1094 *
1095 * tftp_receive_packet
1096 *
1097 * Called once select fires and data is ready on the socket
1098 *
1099 **********************************************************/
1100static CURLcode tftp_receive_packet(struct Curl_easy *data)
1101{
1102 struct Curl_sockaddr_storage fromaddr;
1103 curl_socklen_t fromlen;
1104 CURLcode result = CURLE_OK;
1105 struct connectdata *conn = data->conn;
1106 struct tftp_state_data *state = conn->proto.tftpc;
1107 struct SingleRequest *k = &data->req;
1108
1109 /* Receive the packet */
1110 fromlen = sizeof(fromaddr);
1111 state->rbytes = (int)recvfrom(state->sockfd,
1112 (void *)state->rpacket.data,
1113 state->blksize + 4,
1114 0,
1115 (struct sockaddr *)&fromaddr,
1116 &fromlen);
1117 if(state->remote_addrlen == 0) {
1118 memcpy(&state->remote_addr, &fromaddr, fromlen);
1119 state->remote_addrlen = fromlen;
1120 }
1121
1122 /* Sanity check packet length */
1123 if(state->rbytes < 4) {
1124 failf(data, "Received too short packet");
1125 /* Not a timeout, but how best to handle it? */
1126 state->event = TFTP_EVENT_TIMEOUT;
1127 }
1128 else {
1129 /* The event is given by the TFTP packet time */
1130 unsigned short event = getrpacketevent(&state->rpacket);
1131 state->event = (tftp_event_t)event;
1132
1133 switch(state->event) {
1134 case TFTP_EVENT_DATA:
1135 /* Don't pass to the client empty or retransmitted packets */
1136 if(state->rbytes > 4 &&
1137 (NEXT_BLOCKNUM(state->block) == getrpacketblock(&state->rpacket))) {
1138 result = Curl_client_write(data, CLIENTWRITE_BODY,
1139 (char *)state->rpacket.data + 4,
1140 state->rbytes-4);
1141 if(result) {
1142 tftp_state_machine(state, TFTP_EVENT_ERROR);
1143 return result;
1144 }
1145 k->bytecount += state->rbytes-4;
1146 Curl_pgrsSetDownloadCounter(data, (curl_off_t) k->bytecount);
1147 }
1148 break;
1149 case TFTP_EVENT_ERROR:
1150 {
1151 unsigned short error = getrpacketblock(&state->rpacket);
1152 char *str = (char *)state->rpacket.data + 4;
1153 size_t strn = state->rbytes - 4;
1154 state->error = (tftp_error_t)error;
1155 if(tftp_strnlen(str, strn) < strn)
1156 infof(data, "TFTP error: %s", str);
1157 break;
1158 }
1159 case TFTP_EVENT_ACK:
1160 break;
1161 case TFTP_EVENT_OACK:
1162 result = tftp_parse_option_ack(state,
1163 (const char *)state->rpacket.data + 2,
1164 state->rbytes-2);
1165 if(result)
1166 return result;
1167 break;
1168 case TFTP_EVENT_RRQ:
1169 case TFTP_EVENT_WRQ:
1170 default:
1171 failf(data, "%s", "Internal error: Unexpected packet");
1172 break;
1173 }
1174
1175 /* Update the progress meter */
1176 if(Curl_pgrsUpdate(data)) {
1177 tftp_state_machine(state, TFTP_EVENT_ERROR);
1178 return CURLE_ABORTED_BY_CALLBACK;
1179 }
1180 }
1181 return result;
1182}
1183
1184/**********************************************************
1185 *
1186 * tftp_state_timeout
1187 *
1188 * Check if timeouts have been reached
1189 *
1190 **********************************************************/
1191static timediff_t tftp_state_timeout(struct Curl_easy *data,
1192 tftp_event_t *event)
1193{
1194 time_t current;
1195 struct connectdata *conn = data->conn;
1196 struct tftp_state_data *state = conn->proto.tftpc;
1197 timediff_t timeout_ms;
1198
1199 if(event)
1200 *event = TFTP_EVENT_NONE;
1201
1202 timeout_ms = Curl_timeleft(state->data, NULL,
1203 (state->state == TFTP_STATE_START));
1204 if(timeout_ms < 0) {
1205 state->error = TFTP_ERR_TIMEOUT;
1206 state->state = TFTP_STATE_FIN;
1207 return 0;
1208 }
1209 time(&current);
1210 if(current > state->rx_time + state->retry_time) {
1211 if(event)
1212 *event = TFTP_EVENT_TIMEOUT;
1213 time(&state->rx_time); /* update even though we received nothing */
1214 }
1215
1216 return timeout_ms;
1217}
1218
1219/**********************************************************
1220 *
1221 * tftp_multi_statemach
1222 *
1223 * Handle single RX socket event and return
1224 *
1225 **********************************************************/
1226static CURLcode tftp_multi_statemach(struct Curl_easy *data, bool *done)
1227{
1228 tftp_event_t event;
1229 CURLcode result = CURLE_OK;
1230 struct connectdata *conn = data->conn;
1231 struct tftp_state_data *state = conn->proto.tftpc;
1232 timediff_t timeout_ms = tftp_state_timeout(data, &event);
1233
1234 *done = FALSE;
1235
1236 if(timeout_ms < 0) {
1237 failf(data, "TFTP response timeout");
1238 return CURLE_OPERATION_TIMEDOUT;
1239 }
1240 if(event != TFTP_EVENT_NONE) {
1241 result = tftp_state_machine(state, event);
1242 if(result)
1243 return result;
1244 *done = (state->state == TFTP_STATE_FIN) ? TRUE : FALSE;
1245 if(*done)
1246 /* Tell curl we're done */
1247 Curl_setup_transfer(data, -1, -1, FALSE, -1);
1248 }
1249 else {
1250 /* no timeouts to handle, check our socket */
1251 int rc = SOCKET_READABLE(state->sockfd, 0);
1252
1253 if(rc == -1) {
1254 /* bail out */
1255 int error = SOCKERRNO;
1256 char buffer[STRERROR_LEN];
1257 failf(data, "%s", Curl_strerror(error, buffer, sizeof(buffer)));
1258 state->event = TFTP_EVENT_ERROR;
1259 }
1260 else if(rc) {
1261 result = tftp_receive_packet(data);
1262 if(result)
1263 return result;
1264 result = tftp_state_machine(state, state->event);
1265 if(result)
1266 return result;
1267 *done = (state->state == TFTP_STATE_FIN) ? TRUE : FALSE;
1268 if(*done)
1269 /* Tell curl we're done */
1270 Curl_setup_transfer(data, -1, -1, FALSE, -1);
1271 }
1272 /* if rc == 0, then select() timed out */
1273 }
1274
1275 return result;
1276}
1277
1278/**********************************************************
1279 *
1280 * tftp_doing
1281 *
1282 * Called from multi.c while DOing
1283 *
1284 **********************************************************/
1285static CURLcode tftp_doing(struct Curl_easy *data, bool *dophase_done)
1286{
1287 CURLcode result;
1288 result = tftp_multi_statemach(data, dophase_done);
1289
1290 if(*dophase_done) {
1291 DEBUGF(infof(data, "DO phase is complete"));
1292 }
1293 else if(!result) {
1294 /* The multi code doesn't have this logic for the DOING state so we
1295 provide it for TFTP since it may do the entire transfer in this
1296 state. */
1297 if(Curl_pgrsUpdate(data))
1298 result = CURLE_ABORTED_BY_CALLBACK;
1299 else
1300 result = Curl_speedcheck(data, Curl_now());
1301 }
1302 return result;
1303}
1304
1305/**********************************************************
1306 *
1307 * tftp_peform
1308 *
1309 * Entry point for transfer from tftp_do, sarts state mach
1310 *
1311 **********************************************************/
1312static CURLcode tftp_perform(struct Curl_easy *data, bool *dophase_done)
1313{
1314 CURLcode result = CURLE_OK;
1315 struct connectdata *conn = data->conn;
1316 struct tftp_state_data *state = conn->proto.tftpc;
1317
1318 *dophase_done = FALSE;
1319
1320 result = tftp_state_machine(state, TFTP_EVENT_INIT);
1321
1322 if((state->state == TFTP_STATE_FIN) || result)
1323 return result;
1324
1325 tftp_multi_statemach(data, dophase_done);
1326
1327 if(*dophase_done)
1328 DEBUGF(infof(data, "DO phase is complete"));
1329
1330 return result;
1331}
1332
1333
1334/**********************************************************
1335 *
1336 * tftp_do
1337 *
1338 * The do callback
1339 *
1340 * This callback initiates the TFTP transfer
1341 *
1342 **********************************************************/
1343
1344static CURLcode tftp_do(struct Curl_easy *data, bool *done)
1345{
1346 struct tftp_state_data *state;
1347 CURLcode result;
1348 struct connectdata *conn = data->conn;
1349
1350 *done = FALSE;
1351
1352 if(!conn->proto.tftpc) {
1353 result = tftp_connect(data, done);
1354 if(result)
1355 return result;
1356 }
1357
1358 state = conn->proto.tftpc;
1359 if(!state)
1360 return CURLE_TFTP_ILLEGAL;
1361
1362 result = tftp_perform(data, done);
1363
1364 /* If tftp_perform() returned an error, use that for return code. If it
1365 was OK, see if tftp_translate_code() has an error. */
1366 if(!result)
1367 /* If we have encountered an internal tftp error, translate it. */
1368 result = tftp_translate_code(state->error);
1369
1370 return result;
1371}
1372
1373static CURLcode tftp_setup_connection(struct Curl_easy *data,
1374 struct connectdata *conn)
1375{
1376 char *type;
1377
1378 conn->transport = TRNSPRT_UDP;
1379
1380 /* TFTP URLs support an extension like ";mode=<typecode>" that
1381 * we'll try to get now! */
1382 type = strstr(data->state.up.path, ";mode=");
1383
1384 if(!type)
1385 type = strstr(conn->host.rawalloc, ";mode=");
1386
1387 if(type) {
1388 char command;
1389 *type = 0; /* it was in the middle of the hostname */
1390 command = Curl_raw_toupper(type[6]);
1391
1392 switch(command) {
1393 case 'A': /* ASCII mode */
1394 case 'N': /* NETASCII mode */
1395 data->state.prefer_ascii = TRUE;
1396 break;
1397
1398 case 'O': /* octet mode */
1399 case 'I': /* binary mode */
1400 default:
1401 /* switch off ASCII */
1402 data->state.prefer_ascii = FALSE;
1403 break;
1404 }
1405 }
1406
1407 return CURLE_OK;
1408}
1409#endif
1410