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/*
* 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 */
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