1/*-
2 * Copyright (c) 1998-2011 Dag-Erling Smørgrav
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
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 * 3. The name of the author may not be used to endorse or promote products
15 *    derived from this software without specific prior written permission
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32/*
33 * Portions of this code were taken from or based on ftpio.c:
34 *
35 * ----------------------------------------------------------------------------
36 * "THE BEER-WARE LICENSE" (Revision 42):
37 * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
38 * can do whatever you want with this stuff. If we meet some day, and you think
39 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
40 * ----------------------------------------------------------------------------
41 *
42 * Major Changelog:
43 *
44 * Dag-Erling Smørgrav
45 * 9 Jun 1998
46 *
47 * Incorporated into libfetch
48 *
49 * Jordan K. Hubbard
50 * 17 Jan 1996
51 *
52 * Turned inside out. Now returns xfers as new file ids, not as a special
53 * `state' of FTP_t
54 *
55 * $ftpioId: ftpio.c,v 1.30 1998/04/11 07:28:53 phk Exp $
56 *
57 */
58
59#include <sys/param.h>
60#include <sys/socket.h>
61#include <netinet/in.h>
62
63#include <ctype.h>
64#include <err.h>
65#include <errno.h>
66#include <fcntl.h>
67#include <netdb.h>
68#include <stdarg.h>
69#include <stdint.h>
70#include <stdio.h>
71#include <stdlib.h>
72#include <string.h>
73#include <time.h>
74#include <unistd.h>
75
76#include "fetch.h"
77#include "common.h"
78#include "ftperr.h"
79
80#define FTP_ANONYMOUS_USER	"anonymous"
81
82#define FTP_CONNECTION_ALREADY_OPEN	125
83#define FTP_OPEN_DATA_CONNECTION	150
84#define FTP_OK				200
85#define FTP_FILE_STATUS			213
86#define FTP_SERVICE_READY		220
87#define FTP_TRANSFER_COMPLETE		226
88#define FTP_PASSIVE_MODE		227
89#define FTP_LPASSIVE_MODE		228
90#define FTP_EPASSIVE_MODE		229
91#define FTP_LOGGED_IN			230
92#define FTP_FILE_ACTION_OK		250
93#define FTP_DIRECTORY_CREATED		257 /* multiple meanings */
94#define FTP_FILE_CREATED		257 /* multiple meanings */
95#define FTP_WORKING_DIRECTORY		257 /* multiple meanings */
96#define FTP_NEED_PASSWORD		331
97#define FTP_NEED_ACCOUNT		332
98#define FTP_FILE_OK			350
99#define FTP_SYNTAX_ERROR		500
100#define FTP_PROTOCOL_ERROR		999
101
102static struct url cached_host;
103static conn_t	*cached_connection;
104
105#define isftpreply(foo)				\
106	(isdigit((unsigned char)foo[0]) &&	\
107	    isdigit((unsigned char)foo[1]) &&	\
108	    isdigit((unsigned char)foo[2]) &&	\
109	    (foo[3] == ' ' || foo[3] == '\0'))
110#define isftpinfo(foo) \
111	(isdigit((unsigned char)foo[0]) &&	\
112	    isdigit((unsigned char)foo[1]) &&	\
113	    isdigit((unsigned char)foo[2]) &&	\
114	    foo[3] == '-')
115
116/*
117 * Translate IPv4 mapped IPv6 address to IPv4 address
118 */
119static void
120unmappedaddr(struct sockaddr_in6 *sin6)
121{
122	struct sockaddr_in *sin4;
123	u_int32_t addr;
124	int port;
125
126	if (sin6->sin6_family != AF_INET6 ||
127	    !IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
128		return;
129	sin4 = (struct sockaddr_in *)sin6;
130	addr = *(u_int32_t *)(uintptr_t)&sin6->sin6_addr.s6_addr[12];
131	port = sin6->sin6_port;
132	memset(sin4, 0, sizeof(struct sockaddr_in));
133	sin4->sin_addr.s_addr = addr;
134	sin4->sin_port = port;
135	sin4->sin_family = AF_INET;
136	sin4->sin_len = sizeof(struct sockaddr_in);
137}
138
139/*
140 * Get server response
141 */
142static int
143ftp_chkerr(conn_t *conn)
144{
145	if (fetch_getln(conn) == -1) {
146		fetch_syserr();
147		return (-1);
148	}
149	if (isftpinfo(conn->buf)) {
150		while (conn->buflen && !isftpreply(conn->buf)) {
151			if (fetch_getln(conn) == -1) {
152				fetch_syserr();
153				return (-1);
154			}
155		}
156	}
157
158	while (conn->buflen &&
159	    isspace((unsigned char)conn->buf[conn->buflen - 1]))
160		conn->buflen--;
161	conn->buf[conn->buflen] = '\0';
162
163	if (!isftpreply(conn->buf)) {
164		ftp_seterr(FTP_PROTOCOL_ERROR);
165		return (-1);
166	}
167
168	conn->err = (conn->buf[0] - '0') * 100
169	    + (conn->buf[1] - '0') * 10
170	    + (conn->buf[2] - '0');
171
172	return (conn->err);
173}
174
175/*
176 * Send a command and check reply
177 */
178static int
179ftp_cmd(conn_t *conn, const char *fmt, ...)
180{
181	va_list ap;
182	size_t len;
183	char *msg;
184	int r;
185
186	va_start(ap, fmt);
187	len = vasprintf(&msg, fmt, ap);
188	va_end(ap);
189
190	if (msg == NULL) {
191		errno = ENOMEM;
192		fetch_syserr();
193		return (-1);
194	}
195
196	r = fetch_putln(conn, msg, len);
197	free(msg);
198
199	if (r == -1) {
200		fetch_syserr();
201		return (-1);
202	}
203
204	return (ftp_chkerr(conn));
205}
206
207/*
208 * Return a pointer to the filename part of a path
209 */
210static const char *
211ftp_filename(const char *file, int *len, int *type)
212{
213	const char *s;
214
215	if ((s = strrchr(file, '/')) == NULL)
216		s = file;
217	else
218		s = s + 1;
219	*len = strlen(s);
220	if (*len > 7 && strncmp(s + *len - 7, ";type=", 6) == 0) {
221		*type = s[*len - 1];
222		*len -= 7;
223	} else {
224		*type = '\0';
225	}
226	return (s);
227}
228
229/*
230 * Get current working directory from the reply to a CWD, PWD or CDUP
231 * command.
232 */
233static int
234ftp_pwd(conn_t *conn, char *pwd, size_t pwdlen)
235{
236	char *src, *dst, *end;
237	int q;
238
239	if (conn->err != FTP_WORKING_DIRECTORY &&
240	    conn->err != FTP_FILE_ACTION_OK)
241		return (FTP_PROTOCOL_ERROR);
242	end = conn->buf + conn->buflen;
243	src = conn->buf + 4;
244	if (src >= end || *src++ != '"')
245		return (FTP_PROTOCOL_ERROR);
246	for (q = 0, dst = pwd; src < end && pwdlen--; ++src) {
247		if (!q && *src == '"')
248			q = 1;
249		else if (q && *src != '"')
250			break;
251		else if (q)
252			*dst++ = '"', q = 0;
253		else
254			*dst++ = *src;
255	}
256	if (!pwdlen)
257		return (FTP_PROTOCOL_ERROR);
258	*dst = '\0';
259#if 0
260	DEBUG(fprintf(stderr, "pwd: [%s]\n", pwd));
261#endif
262	return (FTP_OK);
263}
264
265/*
266 * Change working directory to the directory that contains the specified
267 * file.
268 */
269static int
270ftp_cwd(conn_t *conn, const char *file)
271{
272	const char *beg, *end;
273	char pwd[PATH_MAX];
274	int e, i, len;
275
276	/* If no slashes in name, no need to change dirs. */
277	if ((end = strrchr(file, '/')) == NULL)
278		return (0);
279	if ((e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
280	    (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
281		ftp_seterr(e);
282		return (-1);
283	}
284	for (;;) {
285		len = strlen(pwd);
286
287		/* Look for a common prefix between PWD and dir to fetch. */
288		for (i = 0; i <= len && i <= end - file; ++i)
289			if (pwd[i] != file[i])
290				break;
291#if 0
292		DEBUG(fprintf(stderr, "have: [%.*s|%s]\n", i, pwd, pwd + i));
293		DEBUG(fprintf(stderr, "want: [%.*s|%s]\n", i, file, file + i));
294#endif
295		/* Keep going up a dir until we have a matching prefix. */
296		if (pwd[i] == '\0' && (file[i - 1] == '/' || file[i] == '/'))
297			break;
298		if ((e = ftp_cmd(conn, "CDUP")) != FTP_FILE_ACTION_OK ||
299		    (e = ftp_cmd(conn, "PWD")) != FTP_WORKING_DIRECTORY ||
300		    (e = ftp_pwd(conn, pwd, sizeof(pwd))) != FTP_OK) {
301			ftp_seterr(e);
302			return (-1);
303		}
304	}
305
306#ifdef FTP_COMBINE_CWDS
307	/* Skip leading slashes, even "////". */
308	for (beg = file + i; beg < end && *beg == '/'; ++beg, ++i)
309		/* nothing */ ;
310
311	/* If there is no trailing dir, we're already there. */
312	if (beg >= end)
313		return (0);
314
315	/* Change to the directory all in one chunk (e.g., foo/bar/baz). */
316	e = ftp_cmd(conn, "CWD %.*s", (int)(end - beg), beg);
317	if (e == FTP_FILE_ACTION_OK)
318		return (0);
319#endif /* FTP_COMBINE_CWDS */
320
321	/* That didn't work so go back to legacy behavior (multiple CWDs). */
322	for (beg = file + i; beg < end; beg = file + i + 1) {
323		while (*beg == '/')
324			++beg, ++i;
325		for (++i; file + i < end && file[i] != '/'; ++i)
326			/* nothing */ ;
327		e = ftp_cmd(conn, "CWD %.*s", file + i - beg, beg);
328		if (e != FTP_FILE_ACTION_OK) {
329			ftp_seterr(e);
330			return (-1);
331		}
332	}
333	return (0);
334}
335
336/*
337 * Set transfer mode and data type
338 */
339static int
340ftp_mode_type(conn_t *conn, int mode, int type)
341{
342	int e;
343
344	switch (mode) {
345	case 0:
346	case 's':
347		mode = 'S';
348	case 'S':
349		break;
350	default:
351		return (FTP_PROTOCOL_ERROR);
352	}
353	if ((e = ftp_cmd(conn, "MODE %c", mode)) != FTP_OK) {
354		if (mode == 'S') {
355			/*
356			 * Stream mode is supposed to be the default - so
357			 * much so that some servers not only do not
358			 * support any other mode, but do not support the
359			 * MODE command at all.
360			 *
361			 * If "MODE S" fails, it is unlikely that we
362			 * previously succeeded in setting a different
363			 * mode.  Therefore, we simply hope that the
364			 * server is already in the correct mode, and
365			 * silently ignore the failure.
366			 */
367		} else {
368			return (e);
369		}
370	}
371
372	switch (type) {
373	case 0:
374	case 'i':
375		type = 'I';
376	case 'I':
377		break;
378	case 'a':
379		type = 'A';
380	case 'A':
381		break;
382	case 'd':
383		type = 'D';
384	case 'D':
385		/* can't handle yet */
386	default:
387		return (FTP_PROTOCOL_ERROR);
388	}
389	if ((e = ftp_cmd(conn, "TYPE %c", type)) != FTP_OK)
390		return (e);
391
392	return (FTP_OK);
393}
394
395/*
396 * Request and parse file stats
397 */
398static int
399ftp_stat(conn_t *conn, const char *file, struct url_stat *us)
400{
401	char *ln;
402	const char *filename;
403	int filenamelen, type;
404	struct tm tm;
405	time_t t;
406	int e;
407
408	us->size = -1;
409	us->atime = us->mtime = 0;
410
411	filename = ftp_filename(file, &filenamelen, &type);
412
413	if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK) {
414		ftp_seterr(e);
415		return (-1);
416	}
417
418	e = ftp_cmd(conn, "SIZE %.*s", filenamelen, filename);
419	if (e != FTP_FILE_STATUS) {
420		ftp_seterr(e);
421		return (-1);
422	}
423	for (ln = conn->buf + 4; *ln && isspace((unsigned char)*ln); ln++)
424		/* nothing */ ;
425	for (us->size = 0; *ln && isdigit((unsigned char)*ln); ln++)
426		us->size = us->size * 10 + *ln - '0';
427	if (*ln && !isspace((unsigned char)*ln)) {
428		ftp_seterr(FTP_PROTOCOL_ERROR);
429		us->size = -1;
430		return (-1);
431	}
432	if (us->size == 0)
433		us->size = -1;
434	DEBUG(fprintf(stderr, "size: [%lld]\n", (long long)us->size));
435
436	e = ftp_cmd(conn, "MDTM %.*s", filenamelen, filename);
437	if (e != FTP_FILE_STATUS) {
438		ftp_seterr(e);
439		return (-1);
440	}
441	for (ln = conn->buf + 4; *ln && isspace((unsigned char)*ln); ln++)
442		/* nothing */ ;
443	switch (strspn(ln, "0123456789")) {
444	case 14:
445		break;
446	case 15:
447		ln++;
448		ln[0] = '2';
449		ln[1] = '0';
450		break;
451	default:
452		ftp_seterr(FTP_PROTOCOL_ERROR);
453		return (-1);
454	}
455	if (sscanf(ln, "%04d%02d%02d%02d%02d%02d",
456	    &tm.tm_year, &tm.tm_mon, &tm.tm_mday,
457	    &tm.tm_hour, &tm.tm_min, &tm.tm_sec) != 6) {
458		ftp_seterr(FTP_PROTOCOL_ERROR);
459		return (-1);
460	}
461	tm.tm_mon--;
462	tm.tm_year -= 1900;
463	tm.tm_isdst = -1;
464	t = timegm(&tm);
465	if (t == (time_t)-1)
466		t = time(NULL);
467	us->mtime = t;
468	us->atime = t;
469	DEBUG(fprintf(stderr,
470	    "last modified: [%04d-%02d-%02d %02d:%02d:%02d]\n",
471	    tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
472	    tm.tm_hour, tm.tm_min, tm.tm_sec));
473	return (0);
474}
475
476/*
477 * I/O functions for FTP
478 */
479struct ftpio {
480	conn_t	*cconn;		/* Control connection */
481	conn_t	*dconn;		/* Data connection */
482	int	 dir;		/* Direction */
483	int	 eof;		/* EOF reached */
484	int	 err;		/* Error code */
485};
486
487static int	 ftp_readfn(void *, char *, int);
488static int	 ftp_writefn(void *, const char *, int);
489static fpos_t	 ftp_seekfn(void *, fpos_t, int);
490static int	 ftp_closefn(void *);
491
492static int
493ftp_readfn(void *v, char *buf, int len)
494{
495	struct ftpio *io;
496	int r;
497
498	io = (struct ftpio *)v;
499	if (io == NULL) {
500		errno = EBADF;
501		return (-1);
502	}
503	if (io->cconn == NULL || io->dconn == NULL || io->dir == O_WRONLY) {
504		errno = EBADF;
505		return (-1);
506	}
507	if (io->err) {
508		errno = io->err;
509		return (-1);
510	}
511	if (io->eof)
512		return (0);
513	r = fetch_read(io->dconn, buf, len);
514	if (r > 0)
515		return (r);
516	if (r == 0) {
517		io->eof = 1;
518		return (0);
519	}
520	if (errno != EINTR)
521		io->err = errno;
522	return (-1);
523}
524
525static int
526ftp_writefn(void *v, const char *buf, int len)
527{
528	struct ftpio *io;
529	int w;
530
531	io = (struct ftpio *)v;
532	if (io == NULL) {
533		errno = EBADF;
534		return (-1);
535	}
536	if (io->cconn == NULL || io->dconn == NULL || io->dir == O_RDONLY) {
537		errno = EBADF;
538		return (-1);
539	}
540	if (io->err) {
541		errno = io->err;
542		return (-1);
543	}
544	w = fetch_write(io->dconn, buf, len);
545	if (w >= 0)
546		return (w);
547	if (errno != EINTR)
548		io->err = errno;
549	return (-1);
550}
551
552static fpos_t
553ftp_seekfn(void *v, fpos_t pos __unused, int whence __unused)
554{
555	struct ftpio *io;
556
557	io = (struct ftpio *)v;
558	if (io == NULL) {
559		errno = EBADF;
560		return (-1);
561	}
562	errno = ESPIPE;
563	return (-1);
564}
565
566static int
567ftp_closefn(void *v)
568{
569	struct ftpio *io;
570	int r;
571
572	io = (struct ftpio *)v;
573	if (io == NULL) {
574		errno = EBADF;
575		return (-1);
576	}
577	if (io->dir == -1)
578		return (0);
579	if (io->cconn == NULL || io->dconn == NULL) {
580		errno = EBADF;
581		return (-1);
582	}
583	fetch_close(io->dconn);
584	io->dir = -1;
585	io->dconn = NULL;
586	DEBUG(fprintf(stderr, "Waiting for final status\n"));
587	r = ftp_chkerr(io->cconn);
588	if (io->cconn == cached_connection && io->cconn->ref == 1)
589		cached_connection = NULL;
590	fetch_close(io->cconn);
591	free(io);
592	return (r == FTP_TRANSFER_COMPLETE) ? 0 : -1;
593}
594
595static FILE *
596ftp_setup(conn_t *cconn, conn_t *dconn, int mode)
597{
598	struct ftpio *io;
599	FILE *f;
600
601	if (cconn == NULL || dconn == NULL)
602		return (NULL);
603	if ((io = malloc(sizeof(*io))) == NULL)
604		return (NULL);
605	io->cconn = cconn;
606	io->dconn = dconn;
607	io->dir = mode;
608	io->eof = io->err = 0;
609	f = funopen(io, ftp_readfn, ftp_writefn, ftp_seekfn, ftp_closefn);
610	if (f == NULL)
611		free(io);
612	return (f);
613}
614
615/*
616 * Transfer file
617 */
618static FILE *
619ftp_transfer(conn_t *conn, const char *oper, const char *file,
620    int mode, off_t offset, const char *flags)
621{
622	struct sockaddr_storage sa;
623	struct sockaddr_in6 *sin6;
624	struct sockaddr_in *sin4;
625	const char *bindaddr;
626	const char *filename;
627	int filenamelen, type;
628	int low, pasv, verbose;
629	int e, sd = -1;
630	socklen_t l;
631	char *s;
632	FILE *df;
633
634	/* check flags */
635	low = CHECK_FLAG('l');
636	pasv = CHECK_FLAG('p') || !CHECK_FLAG('P');
637	verbose = CHECK_FLAG('v');
638
639	/* passive mode */
640	if ((s = getenv("FTP_PASSIVE_MODE")) != NULL)
641		pasv = (strncasecmp(s, "no", 2) != 0);
642
643	/* isolate filename */
644	filename = ftp_filename(file, &filenamelen, &type);
645
646	/* set transfer mode and data type */
647	if ((e = ftp_mode_type(conn, 0, type)) != FTP_OK)
648		goto ouch;
649
650	/* find our own address, bind, and listen */
651	l = sizeof(sa);
652	if (getsockname(conn->sd, (struct sockaddr *)&sa, &l) == -1)
653		goto sysouch;
654	if (sa.ss_family == AF_INET6)
655		unmappedaddr((struct sockaddr_in6 *)&sa);
656
657	/* open data socket */
658	if ((sd = socket(sa.ss_family, SOCK_STREAM, IPPROTO_TCP)) == -1) {
659		fetch_syserr();
660		return (NULL);
661	}
662
663	if (pasv) {
664		u_char addr[64];
665		char *ln, *p;
666		unsigned int i;
667		int port;
668
669		/* send PASV command */
670		if (verbose)
671			fetch_info("setting passive mode");
672		switch (sa.ss_family) {
673		case AF_INET:
674			if ((e = ftp_cmd(conn, "PASV")) != FTP_PASSIVE_MODE)
675				goto ouch;
676			break;
677		case AF_INET6:
678			if ((e = ftp_cmd(conn, "EPSV")) != FTP_EPASSIVE_MODE) {
679				if (e == -1)
680					goto ouch;
681				if ((e = ftp_cmd(conn, "LPSV")) !=
682				    FTP_LPASSIVE_MODE)
683					goto ouch;
684			}
685			break;
686		default:
687			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
688			goto ouch;
689		}
690
691		/*
692		 * Find address and port number. The reply to the PASV command
693		 * is IMHO the one and only weak point in the FTP protocol.
694		 */
695		ln = conn->buf;
696		switch (e) {
697		case FTP_PASSIVE_MODE:
698		case FTP_LPASSIVE_MODE:
699			for (p = ln + 3; *p && !isdigit((unsigned char)*p); p++)
700				/* nothing */ ;
701			if (!*p) {
702				e = FTP_PROTOCOL_ERROR;
703				goto ouch;
704			}
705			l = (e == FTP_PASSIVE_MODE ? 6 : 21);
706			for (i = 0; *p && i < l; i++, p++)
707				addr[i] = strtol(p, &p, 10);
708			if (i < l) {
709				e = FTP_PROTOCOL_ERROR;
710				goto ouch;
711			}
712			break;
713		case FTP_EPASSIVE_MODE:
714			for (p = ln + 3; *p && *p != '('; p++)
715				/* nothing */ ;
716			if (!*p) {
717				e = FTP_PROTOCOL_ERROR;
718				goto ouch;
719			}
720			++p;
721			if (sscanf(p, "%c%c%c%d%c", &addr[0], &addr[1], &addr[2],
722				&port, &addr[3]) != 5 ||
723			    addr[0] != addr[1] ||
724			    addr[0] != addr[2] || addr[0] != addr[3]) {
725				e = FTP_PROTOCOL_ERROR;
726				goto ouch;
727			}
728			break;
729		}
730
731		/* seek to required offset */
732		if (offset)
733			if (ftp_cmd(conn, "REST %lu", (u_long)offset) != FTP_FILE_OK)
734				goto sysouch;
735
736		/* construct sockaddr for data socket */
737		l = sizeof(sa);
738		if (getpeername(conn->sd, (struct sockaddr *)&sa, &l) == -1)
739			goto sysouch;
740		if (sa.ss_family == AF_INET6)
741			unmappedaddr((struct sockaddr_in6 *)&sa);
742		switch (sa.ss_family) {
743		case AF_INET6:
744			sin6 = (struct sockaddr_in6 *)&sa;
745			if (e == FTP_EPASSIVE_MODE)
746				sin6->sin6_port = htons(port);
747			else {
748				memcpy(&sin6->sin6_addr, addr + 2, 16);
749				memcpy(&sin6->sin6_port, addr + 19, 2);
750			}
751			break;
752		case AF_INET:
753			sin4 = (struct sockaddr_in *)&sa;
754			if (e == FTP_EPASSIVE_MODE)
755				sin4->sin_port = htons(port);
756			else {
757				memcpy(&sin4->sin_addr, addr, 4);
758				memcpy(&sin4->sin_port, addr + 4, 2);
759			}
760			break;
761		default:
762			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
763			break;
764		}
765
766		/* connect to data port */
767		if (verbose)
768			fetch_info("opening data connection");
769		bindaddr = getenv("FETCH_BIND_ADDRESS");
770		if (bindaddr != NULL && *bindaddr != '\0' &&
771		    fetch_bind(sd, sa.ss_family, bindaddr) != 0)
772			goto sysouch;
773		if (connect(sd, (struct sockaddr *)&sa, sa.ss_len) == -1)
774			goto sysouch;
775
776		/* make the server initiate the transfer */
777		if (verbose)
778			fetch_info("initiating transfer");
779		e = ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
780		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
781			goto ouch;
782
783	} else {
784		u_int32_t a;
785		u_short p;
786		int arg, d;
787		char *ap;
788		char hname[INET6_ADDRSTRLEN];
789
790		switch (sa.ss_family) {
791		case AF_INET6:
792			((struct sockaddr_in6 *)&sa)->sin6_port = 0;
793#ifdef IPV6_PORTRANGE
794			arg = low ? IPV6_PORTRANGE_DEFAULT : IPV6_PORTRANGE_HIGH;
795			if (setsockopt(sd, IPPROTO_IPV6, IPV6_PORTRANGE,
796				(char *)&arg, sizeof(arg)) == -1)
797				goto sysouch;
798#endif
799			break;
800		case AF_INET:
801			((struct sockaddr_in *)&sa)->sin_port = 0;
802			arg = low ? IP_PORTRANGE_DEFAULT : IP_PORTRANGE_HIGH;
803			if (setsockopt(sd, IPPROTO_IP, IP_PORTRANGE,
804				(char *)&arg, sizeof(arg)) == -1)
805				goto sysouch;
806			break;
807		}
808		if (verbose)
809			fetch_info("binding data socket");
810		if (bind(sd, (struct sockaddr *)&sa, sa.ss_len) == -1)
811			goto sysouch;
812		if (listen(sd, 1) == -1)
813			goto sysouch;
814
815		/* find what port we're on and tell the server */
816		if (getsockname(sd, (struct sockaddr *)&sa, &l) == -1)
817			goto sysouch;
818		switch (sa.ss_family) {
819		case AF_INET:
820			sin4 = (struct sockaddr_in *)&sa;
821			a = ntohl(sin4->sin_addr.s_addr);
822			p = ntohs(sin4->sin_port);
823			e = ftp_cmd(conn, "PORT %d,%d,%d,%d,%d,%d",
824			    (a >> 24) & 0xff, (a >> 16) & 0xff,
825			    (a >> 8) & 0xff, a & 0xff,
826			    (p >> 8) & 0xff, p & 0xff);
827			break;
828		case AF_INET6:
829#define UC(b)	(((int)b)&0xff)
830			e = -1;
831			sin6 = (struct sockaddr_in6 *)&sa;
832			sin6->sin6_scope_id = 0;
833			if (getnameinfo((struct sockaddr *)&sa, sa.ss_len,
834				hname, sizeof(hname),
835				NULL, 0, NI_NUMERICHOST) == 0) {
836				e = ftp_cmd(conn, "EPRT |%d|%s|%d|", 2, hname,
837				    htons(sin6->sin6_port));
838				if (e == -1)
839					goto ouch;
840			}
841			if (e != FTP_OK) {
842				ap = (char *)&sin6->sin6_addr;
843				e = ftp_cmd(conn,
844				    "LPRT %d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d,%d",
845				    6, 16,
846				    UC(ap[0]), UC(ap[1]), UC(ap[2]), UC(ap[3]),
847				    UC(ap[4]), UC(ap[5]), UC(ap[6]), UC(ap[7]),
848				    UC(ap[8]), UC(ap[9]), UC(ap[10]), UC(ap[11]),
849				    UC(ap[12]), UC(ap[13]), UC(ap[14]), UC(ap[15]),
850				    2,
851				    (ntohs(sin6->sin6_port) >> 8) & 0xff,
852				    ntohs(sin6->sin6_port)        & 0xff);
853			}
854			break;
855		default:
856			e = FTP_PROTOCOL_ERROR; /* XXX: error code should be prepared */
857			goto ouch;
858		}
859		if (e != FTP_OK)
860			goto ouch;
861
862		/* seek to required offset */
863		if (offset)
864			if (ftp_cmd(conn, "REST %ju", (uintmax_t)offset) != FTP_FILE_OK)
865				goto sysouch;
866
867		/* make the server initiate the transfer */
868		if (verbose)
869			fetch_info("initiating transfer");
870		e = ftp_cmd(conn, "%s %.*s", oper, filenamelen, filename);
871		if (e != FTP_CONNECTION_ALREADY_OPEN && e != FTP_OPEN_DATA_CONNECTION)
872			goto ouch;
873
874		/* accept the incoming connection and go to town */
875		if ((d = accept(sd, NULL, NULL)) == -1)
876			goto sysouch;
877		close(sd);
878		sd = d;
879	}
880
881	if ((df = ftp_setup(conn, fetch_reopen(sd), mode)) == NULL)
882		goto sysouch;
883	return (df);
884
885sysouch:
886	fetch_syserr();
887	if (sd >= 0)
888		close(sd);
889	return (NULL);
890
891ouch:
892	if (e != -1)
893		ftp_seterr(e);
894	if (sd >= 0)
895		close(sd);
896	return (NULL);
897}
898
899/*
900 * Authenticate
901 */
902static int
903ftp_authenticate(conn_t *conn, struct url *url, struct url *purl)
904{
905	const char *user, *pwd, *logname;
906	char pbuf[MAXHOSTNAMELEN + MAXLOGNAME + 1];
907	int e, len;
908
909	/* XXX FTP_AUTH, and maybe .netrc */
910
911	/* send user name and password */
912	if (url->user[0] == '\0')
913		fetch_netrc_auth(url);
914	user = url->user;
915	if (*user == '\0')
916		user = getenv("FTP_LOGIN");
917	if (user == NULL || *user == '\0')
918		user = FTP_ANONYMOUS_USER;
919	if (purl && url->port == fetch_default_port(url->scheme))
920		e = ftp_cmd(conn, "USER %s@%s", user, url->host);
921	else if (purl)
922		e = ftp_cmd(conn, "USER %s@%s@%d", user, url->host, url->port);
923	else
924		e = ftp_cmd(conn, "USER %s", user);
925
926	/* did the server request a password? */
927	if (e == FTP_NEED_PASSWORD) {
928		pwd = url->pwd;
929		if (*pwd == '\0')
930			pwd = getenv("FTP_PASSWORD");
931		if (pwd == NULL || *pwd == '\0') {
932			if ((logname = getlogin()) == 0)
933				logname = FTP_ANONYMOUS_USER;
934			if ((len = snprintf(pbuf, MAXLOGNAME + 1, "%s@", logname)) < 0)
935				len = 0;
936			else if (len > MAXLOGNAME)
937				len = MAXLOGNAME;
938			gethostname(pbuf + len, sizeof(pbuf) - len);
939			pwd = pbuf;
940		}
941		e = ftp_cmd(conn, "PASS %s", pwd);
942	}
943
944	return (e);
945}
946
947/*
948 * Log on to FTP server
949 */
950static conn_t *
951ftp_connect(struct url *url, struct url *purl, const char *flags)
952{
953	conn_t *conn;
954	int e, direct, verbose;
955#ifdef INET6
956	int af = AF_UNSPEC;
957#else
958	int af = AF_INET;
959#endif
960
961	direct = CHECK_FLAG('d');
962	verbose = CHECK_FLAG('v');
963	if (CHECK_FLAG('4'))
964		af = AF_INET;
965	else if (CHECK_FLAG('6'))
966		af = AF_INET6;
967
968	if (direct)
969		purl = NULL;
970
971	/* check for proxy */
972	if (purl) {
973		/* XXX proxy authentication! */
974		conn = fetch_connect(purl->host, purl->port, af, verbose);
975	} else {
976		/* no proxy, go straight to target */
977		conn = fetch_connect(url->host, url->port, af, verbose);
978		purl = NULL;
979	}
980
981	/* check connection */
982	if (conn == NULL)
983		/* fetch_connect() has already set an error code */
984		return (NULL);
985
986	/* expect welcome message */
987	if ((e = ftp_chkerr(conn)) != FTP_SERVICE_READY)
988		goto fouch;
989
990	/* authenticate */
991	if ((e = ftp_authenticate(conn, url, purl)) != FTP_LOGGED_IN)
992		goto fouch;
993
994	/* TODO: Request extended features supported, if any (RFC 3659). */
995
996	/* done */
997	return (conn);
998
999fouch:
1000	if (e != -1)
1001		ftp_seterr(e);
1002	fetch_close(conn);
1003	return (NULL);
1004}
1005
1006/*
1007 * Disconnect from server
1008 */
1009static void
1010ftp_disconnect(conn_t *conn)
1011{
1012	(void)ftp_cmd(conn, "QUIT");
1013	if (conn == cached_connection && conn->ref == 1)
1014		cached_connection = NULL;
1015	fetch_close(conn);
1016}
1017
1018/*
1019 * Check if we're already connected
1020 */
1021static int
1022ftp_isconnected(struct url *url)
1023{
1024	return (cached_connection
1025	    && (strcmp(url->host, cached_host.host) == 0)
1026	    && (strcmp(url->user, cached_host.user) == 0)
1027	    && (strcmp(url->pwd, cached_host.pwd) == 0)
1028	    && (url->port == cached_host.port));
1029}
1030
1031/*
1032 * Check the cache, reconnect if no luck
1033 */
1034static conn_t *
1035ftp_cached_connect(struct url *url, struct url *purl, const char *flags)
1036{
1037	conn_t *conn;
1038	int e;
1039
1040	/* set default port */
1041	if (!url->port)
1042		url->port = fetch_default_port(url->scheme);
1043
1044	/* try to use previously cached connection */
1045	if (ftp_isconnected(url)) {
1046		e = ftp_cmd(cached_connection, "NOOP");
1047		if (e == FTP_OK || e == FTP_SYNTAX_ERROR)
1048			return (fetch_ref(cached_connection));
1049	}
1050
1051	/* connect to server */
1052	if ((conn = ftp_connect(url, purl, flags)) == NULL)
1053		return (NULL);
1054	if (cached_connection)
1055		ftp_disconnect(cached_connection);
1056	cached_connection = fetch_ref(conn);
1057	memcpy(&cached_host, url, sizeof(*url));
1058	return (conn);
1059}
1060
1061/*
1062 * Check the proxy settings
1063 */
1064static struct url *
1065ftp_get_proxy(struct url * url, const char *flags)
1066{
1067	struct url *purl;
1068	char *p;
1069
1070	if (flags != NULL && strchr(flags, 'd') != NULL)
1071		return (NULL);
1072	if (fetch_no_proxy_match(url->host))
1073		return (NULL);
1074	if (((p = getenv("FTP_PROXY")) || (p = getenv("ftp_proxy")) ||
1075		(p = getenv("HTTP_PROXY")) || (p = getenv("http_proxy"))) &&
1076	    *p && (purl = fetchParseURL(p)) != NULL) {
1077		if (!*purl->scheme) {
1078			if (getenv("FTP_PROXY") || getenv("ftp_proxy"))
1079				strcpy(purl->scheme, SCHEME_FTP);
1080			else
1081				strcpy(purl->scheme, SCHEME_HTTP);
1082		}
1083		if (!purl->port)
1084			purl->port = fetch_default_proxy_port(purl->scheme);
1085		if (strcasecmp(purl->scheme, SCHEME_FTP) == 0 ||
1086		    strcasecmp(purl->scheme, SCHEME_HTTP) == 0)
1087			return (purl);
1088		fetchFreeURL(purl);
1089	}
1090	return (NULL);
1091}
1092
1093/*
1094 * Process an FTP request
1095 */
1096FILE *
1097ftp_request(struct url *url, const char *op, struct url_stat *us,
1098    struct url *purl, const char *flags)
1099{
1100	conn_t *conn;
1101	int oflag;
1102
1103	/* check if we should use HTTP instead */
1104	if (purl && strcasecmp(purl->scheme, SCHEME_HTTP) == 0) {
1105		if (strcmp(op, "STAT") == 0)
1106			return (http_request(url, "HEAD", us, purl, flags));
1107		else if (strcmp(op, "RETR") == 0)
1108			return (http_request(url, "GET", us, purl, flags));
1109		/*
1110		 * Our HTTP code doesn't support PUT requests yet, so try
1111		 * a direct connection.
1112		 */
1113	}
1114
1115	/* connect to server */
1116	conn = ftp_cached_connect(url, purl, flags);
1117	if (purl)
1118		fetchFreeURL(purl);
1119	if (conn == NULL)
1120		return (NULL);
1121
1122	/* change directory */
1123	if (ftp_cwd(conn, url->doc) == -1)
1124		goto errsock;
1125
1126	/* stat file */
1127	if (us && ftp_stat(conn, url->doc, us) == -1
1128	    && fetchLastErrCode != FETCH_PROTO
1129	    && fetchLastErrCode != FETCH_UNAVAIL)
1130		goto errsock;
1131
1132	/* just a stat */
1133	if (strcmp(op, "STAT") == 0) {
1134		--conn->ref;
1135		ftp_disconnect(conn);
1136		return (FILE *)1; /* bogus return value */
1137	}
1138	if (strcmp(op, "STOR") == 0 || strcmp(op, "APPE") == 0)
1139		oflag = O_WRONLY;
1140	else
1141		oflag = O_RDONLY;
1142
1143	/* initiate the transfer */
1144	return (ftp_transfer(conn, op, url->doc, oflag, url->offset, flags));
1145
1146errsock:
1147	ftp_disconnect(conn);
1148	return (NULL);
1149}
1150
1151/*
1152 * Get and stat file
1153 */
1154FILE *
1155fetchXGetFTP(struct url *url, struct url_stat *us, const char *flags)
1156{
1157	return (ftp_request(url, "RETR", us, ftp_get_proxy(url, flags), flags));
1158}
1159
1160/*
1161 * Get file
1162 */
1163FILE *
1164fetchGetFTP(struct url *url, const char *flags)
1165{
1166	return (fetchXGetFTP(url, NULL, flags));
1167}
1168
1169/*
1170 * Put file
1171 */
1172FILE *
1173fetchPutFTP(struct url *url, const char *flags)
1174{
1175	return (ftp_request(url, CHECK_FLAG('a') ? "APPE" : "STOR", NULL,
1176	    ftp_get_proxy(url, flags), flags));
1177}
1178
1179/*
1180 * Get file stats
1181 */
1182int
1183fetchStatFTP(struct url *url, struct url_stat *us, const char *flags)
1184{
1185	FILE *f;
1186
1187	f = ftp_request(url, "STAT", us, ftp_get_proxy(url, flags), flags);
1188	if (f == NULL)
1189		return (-1);
1190	/*
1191	 * When op is "STAT", ftp_request() will return either NULL or
1192	 * (FILE *)1, never a valid FILE *, so we mustn't fclose(f) before
1193	 * returning, as it would cause a segfault.
1194	 */
1195	return (0);
1196}
1197
1198/*
1199 * List a directory
1200 */
1201struct url_ent *
1202fetchListFTP(struct url *url __unused, const char *flags __unused)
1203{
1204	warnx("fetchListFTP(): not implemented");
1205	return (NULL);
1206}
1207