1 /**
2 *
3 * @file tftp.c
4 *
5 * @author Logan Gunthorpe <logang@deltatee.com>
6 * Dirk Ziegelmeier <dziegel@gmx.de>
7 *
8 * @brief Trivial File Transfer Protocol (RFC 1350)
9 *
10 * Copyright (c) Deltatee Enterprises Ltd. 2013
11 * All rights reserved.
12 *
13 */
14
15 /*
16 * Redistribution and use in source and binary forms, with or without
17 * modification,are permitted provided that the following conditions are met:
18 *
19 * 1. Redistributions of source code must retain the above copyright notice,
20 * this list of conditions and the following disclaimer.
21 * 2. Redistributions in binary form must reproduce the above copyright notice,
22 * this list of conditions and the following disclaimer in the documentation
23 * and/or other materials provided with the distribution.
24 * 3. The name of the author may not be used to endorse or promote products
25 * derived from this software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
28 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
29 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
30 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
31 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
32 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
33 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
34 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
35 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
36 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
37 *
38 * Author: Logan Gunthorpe <logang@deltatee.com>
39 * Dirk Ziegelmeier <dziegel@gmx.de>
40 *
41 */
42
43 /**
44 * @defgroup tftp TFTP client/server
45 * @ingroup apps
46 *
47 * This is simple TFTP client/server for the lwIP raw API.
48 * You need to increase MEMP_NUM_SYS_TIMEOUT by one if you use TFTP!
49 */
50
51 #include "lwip/apps/tftp_client.h"
52 #include "lwip/apps/tftp_server.h"
53
54 #if LWIP_UDP
55
56 #include "lwip/udp.h"
57 #include "lwip/timeouts.h"
58 #include "lwip/debug.h"
59
60 #define TFTP_MAX_PAYLOAD_SIZE 512
61 #define TFTP_HEADER_LENGTH 4
62
63 #define TFTP_RRQ 1
64 #define TFTP_WRQ 2
65 #define TFTP_DATA 3
66 #define TFTP_ACK 4
67 #define TFTP_ERROR 5
68
69 enum tftp_error {
70 TFTP_ERROR_FILE_NOT_FOUND = 1,
71 TFTP_ERROR_ACCESS_VIOLATION = 2,
72 TFTP_ERROR_DISK_FULL = 3,
73 TFTP_ERROR_ILLEGAL_OPERATION = 4,
74 TFTP_ERROR_UNKNOWN_TRFR_ID = 5,
75 TFTP_ERROR_FILE_EXISTS = 6,
76 TFTP_ERROR_NO_SUCH_USER = 7
77 };
78
79 #include <string.h>
80
81 struct tftp_state {
82 const struct tftp_context *ctx;
83 void *handle;
84 struct pbuf *last_data;
85 struct udp_pcb *upcb;
86 ip_addr_t addr;
87 u16_t port;
88 int timer;
89 int last_pkt;
90 u16_t blknum;
91 u8_t retries;
92 u8_t mode_write;
93 u8_t tftp_mode;
94 };
95
96 static struct tftp_state tftp_state;
97
98 static void tftp_tmr(void *arg);
99
100 static void
close_handle(void)101 close_handle(void)
102 {
103 tftp_state.port = 0;
104 ip_addr_set_any(0, &tftp_state.addr);
105
106 if (tftp_state.last_data != NULL) {
107 pbuf_free(tftp_state.last_data);
108 tftp_state.last_data = NULL;
109 }
110
111 sys_untimeout(tftp_tmr, NULL);
112
113 if (tftp_state.handle) {
114 tftp_state.ctx->close(tftp_state.handle);
115 tftp_state.handle = NULL;
116 LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: closing\n"));
117 }
118 }
119
120 static struct pbuf*
init_packet(u16_t opcode,u16_t extra,size_t size)121 init_packet(u16_t opcode, u16_t extra, size_t size)
122 {
123 struct pbuf* p = pbuf_alloc(PBUF_TRANSPORT, (u16_t)(TFTP_HEADER_LENGTH + size), PBUF_RAM);
124 u16_t* payload;
125
126 if (p != NULL) {
127 payload = (u16_t*) p->payload;
128 payload[0] = PP_HTONS(opcode);
129 payload[1] = lwip_htons(extra);
130 }
131
132 return p;
133 }
134
135 static err_t
send_request(const ip_addr_t * addr,u16_t port,u16_t opcode,const char * fname,const char * mode)136 send_request(const ip_addr_t *addr, u16_t port, u16_t opcode, const char* fname, const char* mode)
137 {
138 size_t fname_length = strlen(fname)+1;
139 size_t mode_length = strlen(mode)+1;
140 struct pbuf* p = init_packet(opcode, 0, fname_length + mode_length - 2);
141 char* payload;
142 err_t ret;
143
144 if (p == NULL) {
145 return ERR_MEM;
146 }
147
148 payload = (char*) p->payload;
149 MEMCPY(payload+2, fname, fname_length);
150 MEMCPY(payload+2+fname_length, mode, mode_length);
151
152 ret = udp_sendto(tftp_state.upcb, p, addr, port);
153 pbuf_free(p);
154 return ret;
155 }
156
157 static err_t
send_error(const ip_addr_t * addr,u16_t port,enum tftp_error code,const char * str)158 send_error(const ip_addr_t *addr, u16_t port, enum tftp_error code, const char *str)
159 {
160 int str_length = strlen(str);
161 struct pbuf *p;
162 u16_t *payload;
163 err_t ret;
164
165 p = init_packet(TFTP_ERROR, code, str_length + 1);
166 if (p == NULL) {
167 return ERR_MEM;
168 }
169
170 payload = (u16_t *) p->payload;
171 MEMCPY(&payload[2], str, str_length + 1);
172
173 ret = udp_sendto(tftp_state.upcb, p, addr, port);
174 pbuf_free(p);
175 return ret;
176 }
177
178 static err_t
send_ack(const ip_addr_t * addr,u16_t port,u16_t blknum)179 send_ack(const ip_addr_t *addr, u16_t port, u16_t blknum)
180 {
181 struct pbuf *p;
182 err_t ret;
183
184 p = init_packet(TFTP_ACK, blknum, 0);
185 if (p == NULL) {
186 return ERR_MEM;
187 }
188
189 ret = udp_sendto(tftp_state.upcb, p, addr, port);
190 pbuf_free(p);
191 return ret;
192 }
193
194 static err_t
resend_data(const ip_addr_t * addr,u16_t port)195 resend_data(const ip_addr_t *addr, u16_t port)
196 {
197 err_t ret;
198 struct pbuf *p = pbuf_alloc(PBUF_TRANSPORT, tftp_state.last_data->len, PBUF_RAM);
199 if (p == NULL) {
200 return ERR_MEM;
201 }
202
203 ret = pbuf_copy(p, tftp_state.last_data);
204 if (ret != ERR_OK) {
205 pbuf_free(p);
206 return ret;
207 }
208
209 ret = udp_sendto(tftp_state.upcb, p, addr, port);
210 pbuf_free(p);
211 return ret;
212 }
213
214 static void
send_data(const ip_addr_t * addr,u16_t port)215 send_data(const ip_addr_t *addr, u16_t port)
216 {
217 u16_t *payload;
218 int ret;
219
220 if (tftp_state.last_data != NULL) {
221 pbuf_free(tftp_state.last_data);
222 }
223
224 tftp_state.last_data = init_packet(TFTP_DATA, tftp_state.blknum, TFTP_MAX_PAYLOAD_SIZE);
225 if (tftp_state.last_data == NULL) {
226 return;
227 }
228
229 payload = (u16_t *) tftp_state.last_data->payload;
230
231 ret = tftp_state.ctx->read(tftp_state.handle, &payload[2], TFTP_MAX_PAYLOAD_SIZE);
232 if (ret < 0) {
233 send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Error occurred while reading the file.");
234 close_handle();
235 return;
236 }
237
238 pbuf_realloc(tftp_state.last_data, (u16_t)(TFTP_HEADER_LENGTH + ret));
239 resend_data(addr, port);
240 }
241
242 static void
tftp_recv(void * arg,struct udp_pcb * upcb,struct pbuf * p,const ip_addr_t * addr,u16_t port)243 tftp_recv(void *arg, struct udp_pcb *upcb, struct pbuf *p, const ip_addr_t *addr, u16_t port)
244 {
245 u16_t *sbuf = (u16_t *) p->payload;
246 int opcode;
247
248 LWIP_UNUSED_ARG(arg);
249 LWIP_UNUSED_ARG(upcb);
250
251 if (((tftp_state.port != 0) && (port != tftp_state.port)) ||
252 (!ip_addr_isany_val(tftp_state.addr) && !ip_addr_eq(&tftp_state.addr, addr))) {
253 send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Only one connection at a time is supported");
254 pbuf_free(p);
255 return;
256 }
257
258 opcode = sbuf[0];
259
260 tftp_state.last_pkt = tftp_state.timer;
261 tftp_state.retries = 0;
262
263 switch (opcode) {
264 case PP_HTONS(TFTP_RRQ): /* fall through */
265 case PP_HTONS(TFTP_WRQ): {
266 const char tftp_null = 0;
267 char filename[TFTP_MAX_FILENAME_LEN + 1];
268 char mode[TFTP_MAX_MODE_LEN + 1];
269 u16_t filename_end_offset;
270 u16_t mode_end_offset;
271
272 if (tftp_state.handle != NULL) {
273 send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Only one connection at a time is supported");
274 break;
275 }
276
277 if ((tftp_state.tftp_mode & LWIP_TFTP_MODE_SERVER) == 0) {
278 send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "TFTP server not enabled");
279 break;
280 }
281
282 sys_timeout(TFTP_TIMER_MSECS, tftp_tmr, NULL);
283
284 /* find \0 in pbuf -> end of filename string */
285 filename_end_offset = pbuf_memfind(p, &tftp_null, sizeof(tftp_null), 2);
286 if ((u16_t)(filename_end_offset - 1) > sizeof(filename)) {
287 send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Filename too long/not NULL terminated");
288 break;
289 }
290 pbuf_copy_partial(p, filename, filename_end_offset - 1, 2);
291
292 /* find \0 in pbuf -> end of mode string */
293 mode_end_offset = pbuf_memfind(p, &tftp_null, sizeof(tftp_null), filename_end_offset + 1);
294 if ((u16_t)(mode_end_offset - filename_end_offset) > sizeof(mode)) {
295 send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Mode too long/not NULL terminated");
296 break;
297 }
298 pbuf_copy_partial(p, mode, mode_end_offset - filename_end_offset, filename_end_offset + 1);
299
300 tftp_state.handle = tftp_state.ctx->open(filename, mode, opcode == PP_HTONS(TFTP_WRQ));
301 tftp_state.blknum = 1;
302
303 if (!tftp_state.handle) {
304 send_error(addr, port, TFTP_ERROR_FILE_NOT_FOUND, "Unable to open requested file.");
305 break;
306 }
307
308 LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: %s request from ", (opcode == PP_HTONS(TFTP_WRQ)) ? "write" : "read"));
309 ip_addr_debug_print(TFTP_DEBUG | LWIP_DBG_STATE, addr);
310 LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, (" for '%s' mode '%s'\n", filename, mode));
311
312 ip_addr_copy(tftp_state.addr, *addr);
313 tftp_state.port = port;
314
315 if (opcode == PP_HTONS(TFTP_WRQ)) {
316 tftp_state.mode_write = 1;
317 send_ack(addr, port, 0);
318 } else {
319 tftp_state.mode_write = 0;
320 send_data(addr, port);
321 }
322
323 break;
324 }
325
326 case PP_HTONS(TFTP_DATA): {
327 int ret;
328 u16_t blknum;
329
330 if (tftp_state.handle == NULL) {
331 send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "No connection");
332 break;
333 }
334
335 if (tftp_state.mode_write != 1) {
336 send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Not a write connection");
337 break;
338 }
339
340 blknum = lwip_ntohs(sbuf[1]);
341 if (blknum == tftp_state.blknum) {
342 pbuf_remove_header(p, TFTP_HEADER_LENGTH);
343
344 ret = tftp_state.ctx->write(tftp_state.handle, p);
345 if (ret < 0) {
346 send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "error writing file");
347 close_handle();
348 } else {
349 send_ack(addr, port, blknum);
350 }
351
352 if (p->tot_len < TFTP_MAX_PAYLOAD_SIZE) {
353 close_handle();
354 } else {
355 tftp_state.blknum++;
356 }
357 } else if ((u16_t)(blknum + 1) == tftp_state.blknum) {
358 /* retransmit of previous block, ack again (casting to u16_t to care for overflow) */
359 send_ack(addr, port, blknum);
360 } else {
361 send_error(addr, port, TFTP_ERROR_UNKNOWN_TRFR_ID, "Wrong block number");
362 }
363 break;
364 }
365
366 case PP_HTONS(TFTP_ACK): {
367 u16_t blknum;
368 int lastpkt;
369
370 if (tftp_state.handle == NULL) {
371 send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "No connection");
372 break;
373 }
374
375 if (tftp_state.mode_write != 0) {
376 send_error(addr, port, TFTP_ERROR_ACCESS_VIOLATION, "Not a read connection");
377 break;
378 }
379
380 blknum = lwip_ntohs(sbuf[1]);
381 if (blknum != tftp_state.blknum) {
382 send_error(addr, port, TFTP_ERROR_UNKNOWN_TRFR_ID, "Wrong block number");
383 break;
384 }
385
386 lastpkt = 0;
387
388 if (tftp_state.last_data != NULL) {
389 lastpkt = tftp_state.last_data->tot_len != (TFTP_MAX_PAYLOAD_SIZE + TFTP_HEADER_LENGTH);
390 }
391
392 if (!lastpkt) {
393 tftp_state.blknum++;
394 send_data(addr, port);
395 } else {
396 close_handle();
397 }
398
399 break;
400 }
401 case PP_HTONS(TFTP_ERROR):
402 if (tftp_state.handle != NULL) {
403 pbuf_remove_header(p, TFTP_HEADER_LENGTH);
404 tftp_state.ctx->error(tftp_state.handle, sbuf[1], (const char*)p->payload, p->len);
405 close_handle();
406 }
407 break;
408 default:
409 send_error(addr, port, TFTP_ERROR_ILLEGAL_OPERATION, "Unknown operation");
410 break;
411 }
412
413 pbuf_free(p);
414 }
415
416 static void
tftp_tmr(void * arg)417 tftp_tmr(void *arg)
418 {
419 LWIP_UNUSED_ARG(arg);
420
421 tftp_state.timer++;
422
423 if (tftp_state.handle == NULL) {
424 return;
425 }
426
427 sys_timeout(TFTP_TIMER_MSECS, tftp_tmr, NULL);
428
429 if ((tftp_state.timer - tftp_state.last_pkt) > (TFTP_TIMEOUT_MSECS / TFTP_TIMER_MSECS)) {
430 if ((tftp_state.last_data != NULL) && (tftp_state.retries < TFTP_MAX_RETRIES)) {
431 LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: timeout, retrying\n"));
432 resend_data(&tftp_state.addr, tftp_state.port);
433 tftp_state.retries++;
434 } else {
435 LWIP_DEBUGF(TFTP_DEBUG | LWIP_DBG_STATE, ("tftp: timeout\n"));
436 close_handle();
437 }
438 }
439 }
440
441 /**
442 * Initialize TFTP client/server.
443 * @param mode TFTP mode (client/server)
444 * @param ctx TFTP callback struct
445 */
446 err_t
tftp_init_common(u8_t mode,const struct tftp_context * ctx)447 tftp_init_common(u8_t mode, const struct tftp_context *ctx)
448 {
449 err_t ret;
450
451 /* LWIP_ASSERT_CORE_LOCKED(); is checked by udp_new() */
452 struct udp_pcb *pcb = udp_new_ip_type(IPADDR_TYPE_ANY);
453 if (pcb == NULL) {
454 return ERR_MEM;
455 }
456
457 ret = udp_bind(pcb, IP_ANY_TYPE, TFTP_PORT);
458 if (ret != ERR_OK) {
459 udp_remove(pcb);
460 return ret;
461 }
462
463 tftp_state.handle = NULL;
464 tftp_state.port = 0;
465 tftp_state.ctx = ctx;
466 tftp_state.timer = 0;
467 tftp_state.last_data = NULL;
468 tftp_state.upcb = pcb;
469 tftp_state.tftp_mode = mode;
470
471 udp_recv(pcb, tftp_recv, NULL);
472
473 return ERR_OK;
474 }
475
476 /** @ingroup tftp
477 * Initialize TFTP server.
478 * @param ctx TFTP callback struct
479 */
480 err_t
tftp_init_server(const struct tftp_context * ctx)481 tftp_init_server(const struct tftp_context *ctx)
482 {
483 return tftp_init_common(LWIP_TFTP_MODE_SERVER, ctx);
484 }
485
486 /** @ingroup tftp
487 * Initialize TFTP client.
488 * @param ctx TFTP callback struct
489 */
490 err_t
tftp_init_client(const struct tftp_context * ctx)491 tftp_init_client(const struct tftp_context *ctx)
492 {
493 return tftp_init_common(LWIP_TFTP_MODE_CLIENT, ctx);
494 }
495
496 /** @ingroup tftp
497 * Deinitialize ("turn off") TFTP client/server.
498 */
tftp_cleanup(void)499 void tftp_cleanup(void)
500 {
501 LWIP_ASSERT("Cleanup called on non-initialized TFTP", tftp_state.upcb != NULL);
502 udp_remove(tftp_state.upcb);
503 close_handle();
504 memset(&tftp_state, 0, sizeof(tftp_state));
505 }
506
507 static const char *
mode_to_string(enum tftp_transfer_mode mode)508 mode_to_string(enum tftp_transfer_mode mode)
509 {
510 if (mode == TFTP_MODE_OCTET) {
511 return "octet";
512 }
513 if (mode == TFTP_MODE_NETASCII) {
514 return "netascii";
515 }
516 if (mode == TFTP_MODE_BINARY) {
517 return "binary";
518 }
519 return NULL;
520 }
521
522 err_t
tftp_get(void * handle,const ip_addr_t * addr,u16_t port,const char * fname,enum tftp_transfer_mode mode)523 tftp_get(void* handle, const ip_addr_t *addr, u16_t port, const char* fname, enum tftp_transfer_mode mode)
524 {
525 LWIP_ERROR("TFTP client is not enabled (tftp_init)", (tftp_state.tftp_mode & LWIP_TFTP_MODE_CLIENT) != 0, return ERR_VAL);
526 LWIP_ERROR("tftp_get: invalid file name", fname != NULL, return ERR_VAL);
527 LWIP_ERROR("tftp_get: invalid mode", mode <= TFTP_MODE_BINARY, return ERR_VAL);
528
529 tftp_state.handle = handle;
530 tftp_state.blknum = 1;
531 tftp_state.mode_write = 1; /* We want to receive data */
532 return send_request(addr, port, TFTP_RRQ, fname, mode_to_string(mode));
533 }
534
535 err_t
tftp_put(void * handle,const ip_addr_t * addr,u16_t port,const char * fname,enum tftp_transfer_mode mode)536 tftp_put(void* handle, const ip_addr_t *addr, u16_t port, const char* fname, enum tftp_transfer_mode mode)
537 {
538 LWIP_ERROR("TFTP client is not enabled (tftp_init)", (tftp_state.tftp_mode & LWIP_TFTP_MODE_CLIENT) != 0, return ERR_VAL);
539 LWIP_ERROR("tftp_put: invalid file name", fname != NULL, return ERR_VAL);
540 LWIP_ERROR("tftp_put: invalid mode", mode <= TFTP_MODE_BINARY, return ERR_VAL);
541
542 tftp_state.handle = handle;
543 tftp_state.blknum = 1;
544 tftp_state.mode_write = 0; /* We want to send data */
545 return send_request(addr, port, TFTP_WRQ, fname, mode_to_string(mode));
546 }
547
548 #endif /* LWIP_UDP */
549