[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 "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_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
	19	#include "log.h"
	20	#include "misc.h"
	21	#include "bufaux.h"
	22
	23	/*
	24	* This is the portable version of the SSH tunnel forwarding, it
	25	* uses some preprocessor definitions for various platform-specific
	26	* settings.
	27	*
	28	* SSH_TUN_LINUX Use the (newer) Linux tun/tap device
	29	* SSH_TUN_COMPAT_AF Translate the OpenBSD address family
	30	* SSH_TUN_PREPEND_AF Prepend/remove the address family
	31	*/
	32
	33	/*
	34	* System-specific tunnel open function
	35	*/
	36
	37	#if defined(SSH_TUN_LINUX)
	38	#include <linux/if_tun.h>
	39
	40	int
	41	sys_tun_open(int tun, int mode)
	42	{
	43	struct ifreq ifr;
	44	int fd = -1;
	45	const char *name = NULL;
	46
	47	if ((fd = open("/dev/net/tun", O_RDWR)) == -1) {
	48	debug("%s: failed to open tunnel control interface: %s",
	49	__func__, strerror(errno));
	50	return (-1);
	51	}
	52
	53	bzero(&ifr, sizeof(ifr));
	54
	55	if (mode == SSH_TUNMODE_ETHERNET) {
	56	ifr.ifr_flags = IFF_TAP;
	57	name = "tap%d";
	58	} else {
	59	ifr.ifr_flags = IFF_TUN;
	60	name = "tun%d";
	61	}
	62	ifr.ifr_flags \|= IFF_NO_PI;
	63
	64	if (tun != SSH_TUNID_ANY) {
65	if (tun > SSH_TUNID_MAX) {
66	debug("%s: invalid tunnel id %x: %s", __func__,
67	tun, strerror(errno));
68	goto failed;
69	}
70	snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), name, tun);
71	}
72
73	if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
74	debug("%s: failed to configure tunnel (mode %d): %s", __func__,
75	mode, strerror(errno));
76	goto failed;
77	}
78
79	if (tun == SSH_TUNID_ANY)
80	debug("%s: tunnel mode %d fd %d", __func__, mode, fd);
81	else
82	debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd);
83
84	return (fd);
85
86	failed:
87	close(fd);
88	return (-1);
89	}
90	#endif /* SSH_TUN_LINUX */
91
0f6cb079	92	#ifdef SSH_TUN_FREEBSD
	93	#include <sys/socket.h>
	94	#include <net/if.h>
	95	#include <net/if_tun.h>
	96
	97	int
	98	sys_tun_open(int tun, int mode)
	99	{
	100	struct ifreq ifr;
	101	char name[100];
	102	int fd = -1, sock, flag;
	103	const char *tunbase = "tun";
	104
	105	if (mode == SSH_TUNMODE_ETHERNET) {
	106	#ifdef SSH_TUN_NO_L2
	107	debug("%s: no layer 2 tunnelling support", __func__);
	108	return (-1);
	109	#else
	110	tunbase = "tap";
	111	#endif
	112	}
	113
	114	/* Open the tunnel device */
	115	if (tun <= SSH_TUNID_MAX) {
	116	snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
	117	fd = open(name, O_RDWR);
	118	} else if (tun == SSH_TUNID_ANY) {
	119	for (tun = 100; tun >= 0; tun--) {
	120	snprintf(name, sizeof(name), "/dev/%s%d",
	121	tunbase, tun);
	122	if ((fd = open(name, O_RDWR)) >= 0)
	123	break;
	124	}
	125	} else {
	126	debug("%s: invalid tunnel %u\n", __func__, tun);
	127	return (-1);
	128	}
	129
	130	if (fd < 0) {
	131	debug("%s: %s open failed: %s", __func__, name,
	132	strerror(errno));
	133	return (-1);
	134	}
	135
	136	/* Turn on tunnel headers */
	137	flag = 1;
	138	#if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF)
	139	if (mode != SSH_TUNMODE_ETHERNET &&
	140	ioctl(fd, TUNSIFHEAD, &flag) == -1) {
	141	debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd,
	142	strerror(errno));
	143	close(fd);
	144	}
	145	#endif
	146
	147	debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
	148
	149	/* Set the tunnel device operation mode */
	150	snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
	151	if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
	152	goto failed;
	153
	154	if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
	155	goto failed;
156	ifr.ifr_flags \|= IFF_UP;
157	if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
158	goto failed;
159
160	close(sock);
161	return (fd);
162
163	failed:
164	if (fd >= 0)
165	close(fd);
166	if (sock >= 0)
167	close(sock);
168	debug("%s: failed to set %s mode %d: %s", __func__, name,
169	mode, strerror(errno));
170	return (-1);
171	}
172	#endif /* SSH_TUN_FREEBSD */
173
e914f53a	174	/*
	175	* System-specific channel filters
	176	*/
	177
	178	#if defined(SSH_TUN_FILTER)
	179	#define OPENBSD_AF_INET 2
	180	#define OPENBSD_AF_INET6 24
	181
	182	int
	183	sys_tun_infilter(struct Channel c, char buf, int len)
	184	{
	185	#if defined(SSH_TUN_PREPEND_AF)
	186	char rbuf[CHAN_RBUF];
0f6cb079	187	struct ip *iph;
e914f53a	188	#endif
	189	u_int32_t *af;
	190	char *ptr = buf;
	191
	192	#if defined(SSH_TUN_PREPEND_AF)
0f6cb079	193	if (len <= 0 \|\| len > (int)(sizeof(rbuf) - sizeof(*af)))
e914f53a	194	return (-1);
	195	ptr = (char *)&rbuf[0];
	196	bcopy(buf, ptr + sizeof(u_int32_t), len);
	197	len += sizeof(u_int32_t);
0f6cb079	198	af = (u_int32_t *)ptr;
	199
	200	iph = (struct ip *)(ptr + sizeof(u_int32_t));
	201	switch (iph->ip_v) {
	202	case 6:
	203	*af = AF_INET6;
	204	break;
	205	case 4:
	206	default:
	207	*af = AF_INET;
	208	break;
	209	}
e914f53a	210	#endif
	211
	212	#if defined(SSH_TUN_COMPAT_AF)
	213	if (len < (int)sizeof(u_int32_t))
	214	return (-1);
	215
	216	af = (u_int32_t *)ptr;
	217	if (*af == htonl(AF_INET6))
	218	*af = htonl(OPENBSD_AF_INET6);
	219	else
	220	*af = htonl(OPENBSD_AF_INET);
	221	#endif
0f6cb079	222
e914f53a	223	buffer_put_string(&c->input, ptr, len);
	224	return (0);
	225	}
	226
	227	u_char *
	228	sys_tun_outfilter(struct Channel c, u_char data, u_int dlen)
	229	{
	230	u_char *buf;
	231	u_int32_t *af;
	232
	233	*data = buffer_get_string(&c->output, dlen);
	234	if (dlen < sizeof(af))
	235	return (NULL);
	236	buf = *data;
	237
	238	#if defined(SSH_TUN_PREPEND_AF)
	239	*dlen -= sizeof(u_int32_t);
	240	buf = *data + sizeof(u_int32_t);
	241	#elif defined(SSH_TUN_COMPAT_AF)
	242	af = ntohl((u_int32_t )buf);
	243	if (*af == OPENBSD_AF_INET6)
	244	*af = htonl(AF_INET6);
	245	else
	246	*af = htonl(AF_INET);
	247	#endif
	248
	249	return (buf);
	250	}
	251	#endif /* SSH_TUN_FILTER */