[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 */

/*
 * 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];
#endif
	u_int32_t *af;
	char *ptr = buf;

#if defined(SSH_TUN_PREPEND_AF)
	if (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);
#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
92	/*
93	* System-specific channel filters
94	*/
95
96	#if defined(SSH_TUN_FILTER)
97	#define OPENBSD_AF_INET 2
98	#define OPENBSD_AF_INET6 24
99
100	int
101	sys_tun_infilter(struct Channel c, char buf, int len)
102	{
103	#if defined(SSH_TUN_PREPEND_AF)
104	char rbuf[CHAN_RBUF];
105	#endif
106	u_int32_t *af;
107	char *ptr = buf;
108
109	#if defined(SSH_TUN_PREPEND_AF)
110	if (len > (int)(sizeof(rbuf) - sizeof(*af)))
111	return (-1);
112	ptr = (char *)&rbuf[0];
113	bcopy(buf, ptr + sizeof(u_int32_t), len);
114	len += sizeof(u_int32_t);
115	#endif
116
117	#if defined(SSH_TUN_COMPAT_AF)
118	if (len < (int)sizeof(u_int32_t))
119	return (-1);
120
121	af = (u_int32_t *)ptr;
122	if (*af == htonl(AF_INET6))
123	*af = htonl(OPENBSD_AF_INET6);
124	else
125	*af = htonl(OPENBSD_AF_INET);
126	#endif
127	buffer_put_string(&c->input, ptr, len);
128	return (0);
129	}
130
131	u_char *
132	sys_tun_outfilter(struct Channel c, u_char data, u_int dlen)
133	{
134	u_char *buf;
135	u_int32_t *af;
136
137	*data = buffer_get_string(&c->output, dlen);
138	if (dlen < sizeof(af))
139	return (NULL);
140	buf = *data;
141
142	#if defined(SSH_TUN_PREPEND_AF)
143	*dlen -= sizeof(u_int32_t);
144	buf = *data + sizeof(u_int32_t);
145	#elif defined(SSH_TUN_COMPAT_AF)
146	af = ntohl((u_int32_t )buf);
147	if (*af == OPENBSD_AF_INET6)
148	*af = htonl(AF_INET6);
149	else
150	*af = htonl(AF_INET);
151	#endif
152
153	return (buf);
154	}
155	#endif /* SSH_TUN_FILTER */