tftp.c revision 92913 
1/*	$NetBSD: tftp.c,v 1.4 1997/09/17 16:57:07 drochner Exp $	 */
2
3/*
4 * Copyright (c) 1996
5 *	Matthias Drochner.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed for the NetBSD Project
18 *	by Matthias Drochner.
19 * 4. The name of the author may not be used to endorse or promote products
20 *    derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD: head/lib/libstand/tftp.c 92913 2002-03-21 23:39:28Z obrien $");
36
37/*
38 * Simple TFTP implementation for libsa.
39 * Assumes:
40 *  - socket descriptor (int) at open_file->f_devdata
41 *  - server host IP in global servip
42 * Restrictions:
43 *  - read only
44 *  - lseek only with SEEK_SET or SEEK_CUR
45 *  - no big time differences between transfers (<tftp timeout)
46 */
47
48#include <sys/types.h>
49#include <sys/stat.h>
50#include <netinet/in.h>
51#include <netinet/udp.h>
52#include <netinet/in_systm.h>
53#include <arpa/tftp.h>
54
55#include <string.h>
56
57#include "stand.h"
58#include "net.h"
59#include "netif.h"
60
61#include "tftp.h"
62
63static int	tftp_open(const char *path, struct open_file *f);
64static int	tftp_close(struct open_file *f);
65static int	tftp_read(struct open_file *f, void *buf, size_t size, size_t *resid);
66static int	tftp_write(struct open_file *f, void *buf, size_t size, size_t *resid);
67static off_t	tftp_seek(struct open_file *f, off_t offset, int where);
68static int	tftp_stat(struct open_file *f, struct stat *sb);
69
70struct fs_ops tftp_fsops = {
71	"tftp",
72	tftp_open,
73	tftp_close,
74	tftp_read,
75	tftp_write,
76	tftp_seek,
77	tftp_stat,
78	null_readdir
79};
80
81extern struct in_addr servip;
82
83static int      tftpport = 2000;
84
85#define RSPACE 520		/* max data packet, rounded up */
86
87struct tftp_handle {
88	struct iodesc  *iodesc;
89	int             currblock;	/* contents of lastdata */
90	int             islastblock;	/* flag */
91	int             validsize;
92	int             off;
93	char           *path;	/* saved for re-requests */
94	struct {
95		u_char header[HEADER_SIZE];
96		struct tftphdr t;
97		u_char space[RSPACE];
98	} lastdata;
99};
100
101static int tftperrors[8] = {
102	0,			/* ??? */
103	ENOENT,
104	EPERM,
105	ENOSPC,
106	EINVAL,			/* ??? */
107	EINVAL,			/* ??? */
108	EEXIST,
109	EINVAL			/* ??? */
110};
111
112static ssize_t
113recvtftp(d, pkt, len, tleft)
114	struct iodesc *d;
115	void  *pkt;
116	ssize_t len;
117	time_t          tleft;
118{
119	struct tftphdr *t;
120
121	errno = 0;
122
123	len = readudp(d, pkt, len, tleft);
124
125	if (len < 4)
126		return (-1);
127
128	t = (struct tftphdr *) pkt;
129	switch (ntohs(t->th_opcode)) {
130	case DATA: {
131		int got;
132
133		if (htons(t->th_block) != d->xid) {
134			/*
135			 * Expected block?
136			 */
137			return (-1);
138		}
139		if (d->xid == 1) {
140			/*
141			 * First data packet from new port.
142			 */
143			struct udphdr *uh;
144			uh = (struct udphdr *) pkt - 1;
145			d->destport = uh->uh_sport;
146		} /* else check uh_sport has not changed??? */
147		got = len - (t->th_data - (char *) t);
148		return got;
149	}
150	case ERROR:
151		if ((unsigned) ntohs(t->th_code) >= 8) {
152			printf("illegal tftp error %d\n", ntohs(t->th_code));
153			errno = EIO;
154		} else {
155#ifdef DEBUG
156			printf("tftp-error %d\n", ntohs(t->th_code));
157#endif
158			errno = tftperrors[ntohs(t->th_code)];
159		}
160		return (-1);
161	default:
162#ifdef DEBUG
163		printf("tftp type %d not handled\n", ntohs(t->th_opcode));
164#endif
165		return (-1);
166	}
167}
168
169/* send request, expect first block (or error) */
170static int
171tftp_makereq(h)
172	struct tftp_handle *h;
173{
174	struct {
175		u_char header[HEADER_SIZE];
176		struct tftphdr  t;
177		u_char space[FNAME_SIZE + 6];
178	} wbuf;
179	char           *wtail;
180	int             l;
181	ssize_t         res;
182	struct tftphdr *t;
183
184	wbuf.t.th_opcode = htons((u_short) RRQ);
185	wtail = wbuf.t.th_stuff;
186	l = strlen(h->path);
187	bcopy(h->path, wtail, l + 1);
188	wtail += l + 1;
189	bcopy("octet", wtail, 6);
190	wtail += 6;
191
192	t = &h->lastdata.t;
193
194	/* h->iodesc->myport = htons(--tftpport); */
195	h->iodesc->myport = htons(tftpport + (getsecs() & 0x3ff));
196	h->iodesc->destport = htons(IPPORT_TFTP);
197	h->iodesc->xid = 1;	/* expected block */
198
199	res = sendrecv(h->iodesc, sendudp, &wbuf.t, wtail - (char *) &wbuf.t,
200		       recvtftp, t, sizeof(*t) + RSPACE);
201
202	if (res == -1)
203		return (errno);
204
205	h->currblock = 1;
206	h->validsize = res;
207	h->islastblock = 0;
208	if (res < SEGSIZE)
209		h->islastblock = 1;	/* very short file */
210	return (0);
211}
212
213/* ack block, expect next */
214static int
215tftp_getnextblock(h)
216	struct tftp_handle *h;
217{
218	struct {
219		u_char header[HEADER_SIZE];
220		struct tftphdr t;
221	} wbuf;
222	char           *wtail;
223	int             res;
224	struct tftphdr *t;
225
226	wbuf.t.th_opcode = htons((u_short) ACK);
227	wtail = (char *) &wbuf.t.th_block;
228	wbuf.t.th_block = htons((u_short) h->currblock);
229	wtail += 2;
230
231	t = &h->lastdata.t;
232
233	h->iodesc->xid = h->currblock + 1;	/* expected block */
234
235	res = sendrecv(h->iodesc, sendudp, &wbuf.t, wtail - (char *) &wbuf.t,
236		       recvtftp, t, sizeof(*t) + RSPACE);
237
238	if (res == -1)		/* 0 is OK! */
239		return (errno);
240
241	h->currblock++;
242	h->validsize = res;
243	if (res < SEGSIZE)
244		h->islastblock = 1;	/* EOF */
245	return (0);
246}
247
248static int
249tftp_open(path, f)
250	const char *path;
251	struct open_file *f;
252{
253	struct tftp_handle *tftpfile;
254	struct iodesc  *io;
255	int             res;
256
257	tftpfile = (struct tftp_handle *) malloc(sizeof(*tftpfile));
258	if (!tftpfile)
259		return (ENOMEM);
260
261	tftpfile->iodesc = io = socktodesc(*(int *) (f->f_devdata));
262	if (io == NULL)
263		return (EINVAL);
264
265	io->destip = servip;
266	tftpfile->off = 0;
267	tftpfile->path = strdup(path);
268	if (tftpfile->path == NULL) {
269	    free(tftpfile);
270	    return(ENOMEM);
271	}
272
273	res = tftp_makereq(tftpfile, path);
274
275	if (res) {
276		free(tftpfile->path);
277		free(tftpfile);
278		return (res);
279	}
280	f->f_fsdata = (void *) tftpfile;
281	return (0);
282}
283
284static int
285tftp_read(f, addr, size, resid)
286	struct open_file *f;
287	void           *addr;
288	size_t          size;
289	size_t         *resid;	/* out */
290{
291	struct tftp_handle *tftpfile;
292	static int      tc = 0;
293	tftpfile = (struct tftp_handle *) f->f_fsdata;
294
295	while (size > 0) {
296		int needblock, count;
297
298		if (!(tc++ % 16))
299			twiddle();
300
301		needblock = tftpfile->off / SEGSIZE + 1;
302
303		if (tftpfile->currblock > needblock)	/* seek backwards */
304			tftp_makereq(tftpfile);	/* no error check, it worked
305						 * for open */
306
307		while (tftpfile->currblock < needblock) {
308			int res;
309
310			res = tftp_getnextblock(tftpfile);
311			if (res) {	/* no answer */
312#ifdef DEBUG
313				printf("tftp: read error\n");
314#endif
315				return (res);
316			}
317			if (tftpfile->islastblock)
318				break;
319		}
320
321		if (tftpfile->currblock == needblock) {
322			int offinblock, inbuffer;
323
324			offinblock = tftpfile->off % SEGSIZE;
325
326			inbuffer = tftpfile->validsize - offinblock;
327			if (inbuffer < 0) {
328#ifdef DEBUG
329				printf("tftp: invalid offset %d\n",
330				    tftpfile->off);
331#endif
332				return (EINVAL);
333			}
334			count = (size < inbuffer ? size : inbuffer);
335			bcopy(tftpfile->lastdata.t.th_data + offinblock,
336			    addr, count);
337
338			addr += count;
339			tftpfile->off += count;
340			size -= count;
341
342			if ((tftpfile->islastblock) && (count == inbuffer))
343				break;	/* EOF */
344		} else {
345#ifdef DEBUG
346			printf("tftp: block %d not found\n", needblock);
347#endif
348			return (EINVAL);
349		}
350
351	}
352
353	if (resid)
354		*resid = size;
355	return (0);
356}
357
358static int
359tftp_close(f)
360	struct open_file *f;
361{
362	struct tftp_handle *tftpfile;
363	tftpfile = (struct tftp_handle *) f->f_fsdata;
364
365	/* let it time out ... */
366
367	if (tftpfile) {
368		free(tftpfile->path);
369		free(tftpfile);
370	}
371	return (0);
372}
373
374static int
375tftp_write(f, start, size, resid)
376	struct open_file *f;
377	void           *start;
378	size_t          size;
379	size_t         *resid;	/* out */
380{
381	return (EROFS);
382}
383
384static int
385tftp_stat(f, sb)
386	struct open_file *f;
387	struct stat    *sb;
388{
389	struct tftp_handle *tftpfile;
390	tftpfile = (struct tftp_handle *) f->f_fsdata;
391
392	sb->st_mode = 0444 | S_IFREG;
393	sb->st_nlink = 1;
394	sb->st_uid = 0;
395	sb->st_gid = 0;
396	sb->st_size = -1;
397	return (0);
398}
399
400static off_t
401tftp_seek(f, offset, where)
402	struct open_file *f;
403	off_t           offset;
404	int             where;
405{
406	struct tftp_handle *tftpfile;
407	tftpfile = (struct tftp_handle *) f->f_fsdata;
408
409	switch (where) {
410	case SEEK_SET:
411		tftpfile->off = offset;
412		break;
413	case SEEK_CUR:
414		tftpfile->off += offset;
415		break;
416	default:
417		errno = EOFFSET;
418		return (-1);
419	}
420	return (tftpfile->off);
421}
422