[openssh.git] / openbsd-compat / port-tun.c

/*
 * Copyright (c) 2005 Reyk Floeter <reyk@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "includes.h"

#include <sys/ioctl.h>
#include <netinet/ip.h>

#include "log.h"
#include "misc.h"
#include "bufaux.h"

/*
 * This is the portable version of the SSH tunnel forwarding, it
 * uses some preprocessor definitions for various platform-specific
 * settings.
 *
 * SSH_TUN_LINUX	Use the (newer) Linux tun/tap device
 * SSH_TUN_COMPAT_AF	Translate the OpenBSD address family
 * SSH_TUN_PREPEND_AF	Prepend/remove the address family
 */

/*
 * System-specific tunnel open function
 */

#if defined(SSH_TUN_LINUX)
#include <linux/if.h>
#include <linux/if_tun.h>

int
sys_tun_open(int tun, int mode)
{
	struct ifreq ifr;
	int fd = -1;
	const char *name = NULL;

	if ((fd = open("/dev/net/tun", O_RDWR)) == -1) {
		debug("%s: failed to open tunnel control interface: %s",
		    __func__, strerror(errno));
		return (-1);
	}

	bzero(&ifr, sizeof(ifr));	

	if (mode == SSH_TUNMODE_ETHERNET) {
		ifr.ifr_flags = IFF_TAP;
		name = "tap%d";
	} else {
		ifr.ifr_flags = IFF_TUN;
		name = "tun%d";
	}
	ifr.ifr_flags |= IFF_NO_PI;

	if (tun != SSH_TUNID_ANY) {
		if (tun > SSH_TUNID_MAX) {
			debug("%s: invalid tunnel id %x: %s", __func__,
			    tun, strerror(errno));
			goto failed;
		}
		snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), name, tun);
	}

	if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
		debug("%s: failed to configure tunnel (mode %d): %s", __func__,
		    mode, strerror(errno));
		goto failed;
	}

	if (tun == SSH_TUNID_ANY)
		debug("%s: tunnel mode %d fd %d", __func__, mode, fd);
	else
		debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd);

	return (fd);

 failed:
	close(fd);
	return (-1);
}
#endif /* SSH_TUN_LINUX */

#ifdef SSH_TUN_FREEBSD
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_tun.h>

int
sys_tun_open(int tun, int mode)
{
	struct ifreq ifr;
	char name[100];
	int fd = -1, sock, flag;
	const char *tunbase = "tun";

	if (mode == SSH_TUNMODE_ETHERNET) {
#ifdef SSH_TUN_NO_L2
		debug("%s: no layer 2 tunnelling support", __func__);
		return (-1);
#else
		tunbase = "tap";
#endif
	}

	/* Open the tunnel device */
	if (tun <= SSH_TUNID_MAX) {
		snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
		fd = open(name, O_RDWR);
	} else if (tun == SSH_TUNID_ANY) {
		for (tun = 100; tun >= 0; tun--) {
			snprintf(name, sizeof(name), "/dev/%s%d",
			    tunbase, tun);
			if ((fd = open(name, O_RDWR)) >= 0)
				break;
		}
	} else {
		debug("%s: invalid tunnel %u\n", __func__, tun);
		return (-1);
	}

	if (fd < 0) {
		debug("%s: %s open failed: %s", __func__, name,
		    strerror(errno));
		return (-1);
	}

	/* Turn on tunnel headers */
	flag = 1;
#if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF)
	if (mode != SSH_TUNMODE_ETHERNET &&
	    ioctl(fd, TUNSIFHEAD, &flag) == -1) {
		debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd,
		    strerror(errno));
		close(fd);
	}
#endif

	debug("%s: %s mode %d fd %d", __func__, name, mode, fd);

	/* Set the tunnel device operation mode */
	snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
	if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
		goto failed;

	if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
		goto failed;
	ifr.ifr_flags |= IFF_UP;
	if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
		goto failed;

	close(sock);
	return (fd);

 failed:
	if (fd >= 0)
		close(fd);
	if (sock >= 0)
		close(sock);
	debug("%s: failed to set %s mode %d: %s", __func__, name,
	    mode, strerror(errno));
	return (-1);
}
#endif /* SSH_TUN_FREEBSD */

/*
 * System-specific channel filters
 */

#if defined(SSH_TUN_FILTER)
#define OPENBSD_AF_INET		2
#define OPENBSD_AF_INET6	24

int
sys_tun_infilter(struct Channel *c, char *buf, int len)
{
#if defined(SSH_TUN_PREPEND_AF)
	char rbuf[CHAN_RBUF];
	struct ip *iph;
#endif
	u_int32_t *af;
	char *ptr = buf;

#if defined(SSH_TUN_PREPEND_AF)
	if (len <= 0 || len > (int)(sizeof(rbuf) - sizeof(*af)))
		return (-1);
	ptr = (char *)&rbuf[0];
	bcopy(buf, ptr + sizeof(u_int32_t), len);
	len += sizeof(u_int32_t);
	af = (u_int32_t *)ptr;

	iph = (struct ip *)(ptr + sizeof(u_int32_t));
	switch (iph->ip_v) {
	case 6:
		*af = AF_INET6;
		break;
	case 4:
	default:
		*af = AF_INET;
		break;
	}
#endif

#if defined(SSH_TUN_COMPAT_AF)
	if (len < (int)sizeof(u_int32_t))
		return (-1);

	af = (u_int32_t *)ptr;
	if (*af == htonl(AF_INET6))
		*af = htonl(OPENBSD_AF_INET6);
	else
		*af = htonl(OPENBSD_AF_INET);
#endif

	buffer_put_string(&c->input, ptr, len);
	return (0);
}

u_char *
sys_tun_outfilter(struct Channel *c, u_char **data, u_int *dlen)
{
	u_char *buf;
	u_int32_t *af;

	*data = buffer_get_string(&c->output, dlen);
	if (*dlen < sizeof(*af))
		return (NULL);
	buf = *data;

#if defined(SSH_TUN_PREPEND_AF)
	*dlen -= sizeof(u_int32_t);
	buf = *data + sizeof(u_int32_t);
#elif defined(SSH_TUN_COMPAT_AF)
	af = ntohl(*(u_int32_t *)buf);
	if (*af == OPENBSD_AF_INET6)
		*af = htonl(AF_INET6);
	else
		*af = htonl(AF_INET);
#endif

	return (buf);
}
#endif /* SSH_TUN_FILTER */
Commit	Line	Data
e914f53a	1	/*
	2	* Copyright (c) 2005 Reyk Floeter <reyk@openbsd.org>
	3	*
	4	* Permission to use, copy, modify, and distribute this software for any
	5	* purpose with or without fee is hereby granted, provided that the above
	6	* copyright notice and this permission notice appear in all copies.
	7	*
	8	* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	9	* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	10	* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
	11	* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	12	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
	13	* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
	14	* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	15	*/
	16
	17	#include "includes.h"
	18
3e9b2b1b	19	#include <sys/ioctl.h>
	20	#include <netinet/ip.h>
	21
e914f53a	22	#include "log.h"
	23	#include "misc.h"
	24	#include "bufaux.h"
	25
	26	/*
	27	* This is the portable version of the SSH tunnel forwarding, it
	28	* uses some preprocessor definitions for various platform-specific
	29	* settings.
	30	*
	31	* SSH_TUN_LINUX Use the (newer) Linux tun/tap device
	32	* SSH_TUN_COMPAT_AF Translate the OpenBSD address family
	33	* SSH_TUN_PREPEND_AF Prepend/remove the address family
	34	*/
	35
	36	/*
	37	* System-specific tunnel open function
	38	*/
	39
	40	#if defined(SSH_TUN_LINUX)
3aef38da	41	#include <linux/if.h>
e914f53a	42	#include <linux/if_tun.h>
	43
	44	int
	45	sys_tun_open(int tun, int mode)
	46	{
	47	struct ifreq ifr;
	48	int fd = -1;
	49	const char *name = NULL;
	50
	51	if ((fd = open("/dev/net/tun", O_RDWR)) == -1) {
	52	debug("%s: failed to open tunnel control interface: %s",
	53	__func__, strerror(errno));
	54	return (-1);
	55	}
	56
	57	bzero(&ifr, sizeof(ifr));
	58
	59	if (mode == SSH_TUNMODE_ETHERNET) {
	60	ifr.ifr_flags = IFF_TAP;
	61	name = "tap%d";
	62	} else {
	63	ifr.ifr_flags = IFF_TUN;
	64	name = "tun%d";
	65	}
	66	ifr.ifr_flags \|= IFF_NO_PI;
	67
	68	if (tun != SSH_TUNID_ANY) {
	69	if (tun > SSH_TUNID_MAX) {
	70	debug("%s: invalid tunnel id %x: %s", __func__,
	71	tun, strerror(errno));
	72	goto failed;
	73	}
	74	snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), name, tun);
	75	}
	76
	77	if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
	78	debug("%s: failed to configure tunnel (mode %d): %s", __func__,
	79	mode, strerror(errno));
	80	goto failed;
	81	}
	82
	83	if (tun == SSH_TUNID_ANY)
	84	debug("%s: tunnel mode %d fd %d", __func__, mode, fd);
	85	else
	86	debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd);
	87
	88	return (fd);
	89
	90	failed:
	91	close(fd);
	92	return (-1);
	93	}
	94	#endif /* SSH_TUN_LINUX */
	95
0f6cb079	96	#ifdef SSH_TUN_FREEBSD
	97	#include <sys/socket.h>
	98	#include <net/if.h>
	99	#include <net/if_tun.h>
	100
	101	int
	102	sys_tun_open(int tun, int mode)
	103	{
	104	struct ifreq ifr;
	105	char name[100];
	106	int fd = -1, sock, flag;
	107	const char *tunbase = "tun";
	108
	109	if (mode == SSH_TUNMODE_ETHERNET) {
	110	#ifdef SSH_TUN_NO_L2
	111	debug("%s: no layer 2 tunnelling support", __func__);
	112	return (-1);
	113	#else
	114	tunbase = "tap";
	115	#endif
	116	}
	117
	118	/* Open the tunnel device */
	119	if (tun <= SSH_TUNID_MAX) {
	120	snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
	121	fd = open(name, O_RDWR);
	122	} else if (tun == SSH_TUNID_ANY) {
	123	for (tun = 100; tun >= 0; tun--) {
	124	snprintf(name, sizeof(name), "/dev/%s%d",
	125	tunbase, tun);
	126	if ((fd = open(name, O_RDWR)) >= 0)
	127	break;
	128	}
	129	} else {
	130	debug("%s: invalid tunnel %u\n", __func__, tun);
	131	return (-1);
	132	}
	133
	134	if (fd < 0) {
	135	debug("%s: %s open failed: %s", __func__, name,
	136	strerror(errno));
	137	return (-1);
	138	}
	139
	140	/* Turn on tunnel headers */
	141	flag = 1;
	142	#if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF)
	143	if (mode != SSH_TUNMODE_ETHERNET &&
	144	ioctl(fd, TUNSIFHEAD, &flag) == -1) {
	145	debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd,
	146	strerror(errno));
	147	close(fd);
	148	}
	149	#endif
	150
	151	debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
	152
	153	/* Set the tunnel device operation mode */
	154	snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
	155	if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
	156	goto failed;
	157
	158	if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
	159	goto failed;
160	ifr.ifr_flags \|= IFF_UP;
161	if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
162	goto failed;
163
164	close(sock);
165	return (fd);
166
167	failed:
168	if (fd >= 0)
169	close(fd);
170	if (sock >= 0)
171	close(sock);
172	debug("%s: failed to set %s mode %d: %s", __func__, name,
173	mode, strerror(errno));
174	return (-1);
175	}
176	#endif /* SSH_TUN_FREEBSD */
177
e914f53a	178	/*
	179	* System-specific channel filters
	180	*/
	181
	182	#if defined(SSH_TUN_FILTER)
	183	#define OPENBSD_AF_INET 2
	184	#define OPENBSD_AF_INET6 24
	185
	186	int
	187	sys_tun_infilter(struct Channel c, char buf, int len)
	188	{
	189	#if defined(SSH_TUN_PREPEND_AF)
	190	char rbuf[CHAN_RBUF];
0f6cb079	191	struct ip *iph;
e914f53a	192	#endif
	193	u_int32_t *af;
	194	char *ptr = buf;
	195
	196	#if defined(SSH_TUN_PREPEND_AF)
0f6cb079	197	if (len <= 0 \|\| len > (int)(sizeof(rbuf) - sizeof(*af)))
e914f53a	198	return (-1);
	199	ptr = (char *)&rbuf[0];
	200	bcopy(buf, ptr + sizeof(u_int32_t), len);
	201	len += sizeof(u_int32_t);
0f6cb079	202	af = (u_int32_t *)ptr;
	203
	204	iph = (struct ip *)(ptr + sizeof(u_int32_t));
	205	switch (iph->ip_v) {
	206	case 6:
	207	*af = AF_INET6;
	208	break;
	209	case 4:
	210	default:
	211	*af = AF_INET;
	212	break;
	213	}
e914f53a	214	#endif
	215
	216	#if defined(SSH_TUN_COMPAT_AF)
	217	if (len < (int)sizeof(u_int32_t))
	218	return (-1);
	219
	220	af = (u_int32_t *)ptr;
	221	if (*af == htonl(AF_INET6))
	222	*af = htonl(OPENBSD_AF_INET6);
	223	else
	224	*af = htonl(OPENBSD_AF_INET);
	225	#endif
0f6cb079	226
e914f53a	227	buffer_put_string(&c->input, ptr, len);
	228	return (0);
	229	}
	230
	231	u_char *
	232	sys_tun_outfilter(struct Channel c, u_char data, u_int dlen)
	233	{
	234	u_char *buf;
	235	u_int32_t *af;
	236
	237	*data = buffer_get_string(&c->output, dlen);
	238	if (dlen < sizeof(af))
	239	return (NULL);
	240	buf = *data;
	241
	242	#if defined(SSH_TUN_PREPEND_AF)
	243	*dlen -= sizeof(u_int32_t);
	244	buf = *data + sizeof(u_int32_t);
	245	#elif defined(SSH_TUN_COMPAT_AF)
	246	af = ntohl((u_int32_t )buf);
	247	if (*af == OPENBSD_AF_INET6)
	248	*af = htonl(AF_INET6);
	249	else
	250	*af = htonl(AF_INET);
	251	#endif
	252
	253	return (buf);
	254	}
	255	#endif /* SSH_TUN_FILTER */