/*
* 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/types.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netinet/ip.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include "openbsd-compat/sys-queue.h"
#include "log.h"
#include "misc.h"
#include "sshbuf.h"
#include "channels.h"
#include "ssherr.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_FREEBSD Use the FreeBSD 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>
#ifdef HAVE_NET_IF_TUN_H
#include <net/if_tun.h>
#endif
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;
if ((ifr.ifr_flags & IFF_UP) == 0) {
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;
int r;
#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
if ((r = sshbuf_put_string(&c->input, ptr, len)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
return (0);
}
u_char *
sys_tun_outfilter(struct Channel *c, u_char **data, u_int *dlen)
{
u_char *buf;
u_int32_t *af;
int r;
size_t xxx_dlen;
/* XXX new API is incompatible with this signature. */
if ((r = sshbuf_get_string(&c->output, data, &xxx_dlen)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
if (dlen != NULL)
*dlen = xxx_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 */