2 * Copyright (c) 2005 Reyk Floeter <reyk@openbsd.org>
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.
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.
19 #include <sys/types.h>
20 #include <sys/ioctl.h>
22 #include <netinet/in.h>
23 #include <arpa/inet.h>
24 #include <netinet/ip.h>
32 #include "openbsd-compat/sys-queue.h"
40 * This is the portable version of the SSH tunnel forwarding, it
41 * uses some preprocessor definitions for various platform-specific
44 * SSH_TUN_LINUX Use the (newer) Linux tun/tap device
45 * SSH_TUN_FREEBSD Use the FreeBSD tun/tap device
46 * SSH_TUN_COMPAT_AF Translate the OpenBSD address family
47 * SSH_TUN_PREPEND_AF Prepend/remove the address family
51 * System-specific tunnel open function
54 #if defined(SSH_TUN_LINUX)
56 #include <linux/if_tun.h>
59 sys_tun_open(int tun, int mode)
63 const char *name = NULL;
65 if ((fd = open("/dev/net/tun", O_RDWR)) == -1) {
66 debug("%s: failed to open tunnel control interface: %s",
67 __func__, strerror(errno));
71 bzero(&ifr, sizeof(ifr));
73 if (mode == SSH_TUNMODE_ETHERNET) {
74 ifr.ifr_flags = IFF_TAP;
77 ifr.ifr_flags = IFF_TUN;
80 ifr.ifr_flags |= IFF_NO_PI;
82 if (tun != SSH_TUNID_ANY) {
83 if (tun > SSH_TUNID_MAX) {
84 debug("%s: invalid tunnel id %x: %s", __func__,
85 tun, strerror(errno));
88 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), name, tun);
91 if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
92 debug("%s: failed to configure tunnel (mode %d): %s", __func__,
93 mode, strerror(errno));
97 if (tun == SSH_TUNID_ANY)
98 debug("%s: tunnel mode %d fd %d", __func__, mode, fd);
100 debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd);
108 #endif /* SSH_TUN_LINUX */
110 #ifdef SSH_TUN_FREEBSD
111 #include <sys/socket.h>
114 #ifdef HAVE_NET_IF_TUN_H
115 #include <net/tun/if_tun.h>
119 sys_tun_open(int tun, int mode)
123 int fd = -1, sock, flag;
124 const char *tunbase = "tun";
126 if (mode == SSH_TUNMODE_ETHERNET) {
128 debug("%s: no layer 2 tunnelling support", __func__);
135 /* Open the tunnel device */
136 if (tun <= SSH_TUNID_MAX) {
137 snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
138 fd = open(name, O_RDWR);
139 } else if (tun == SSH_TUNID_ANY) {
140 for (tun = 100; tun >= 0; tun--) {
141 snprintf(name, sizeof(name), "/dev/%s%d",
143 if ((fd = open(name, O_RDWR)) >= 0)
147 debug("%s: invalid tunnel %u\n", __func__, tun);
152 debug("%s: %s open failed: %s", __func__, name,
157 /* Turn on tunnel headers */
159 #if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF)
160 if (mode != SSH_TUNMODE_ETHERNET &&
161 ioctl(fd, TUNSIFHEAD, &flag) == -1) {
162 debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd,
168 debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
170 /* Set the tunnel device operation mode */
171 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
172 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
175 if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
177 if ((ifr.ifr_flags & IFF_UP) == 0) {
178 ifr.ifr_flags |= IFF_UP;
179 if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
191 debug("%s: failed to set %s mode %d: %s", __func__, name,
192 mode, strerror(errno));
195 #endif /* SSH_TUN_FREEBSD */
198 * System-specific channel filters
201 #if defined(SSH_TUN_FILTER)
203 * The tunnel forwarding protocol prepends the address family of forwarded
204 * IP packets using OpenBSD's numbers.
206 #define OPENBSD_AF_INET 2
207 #define OPENBSD_AF_INET6 24
210 sys_tun_infilter(struct ssh *ssh, struct Channel *c, char *buf, int _len)
215 #if defined(SSH_TUN_PREPEND_AF)
216 char rbuf[CHAN_RBUF];
219 #if defined(SSH_TUN_PREPEND_AF) || defined(SSH_TUN_COMPAT_AF)
223 /* XXX update channel input filter API to use unsigned length */
228 #if defined(SSH_TUN_PREPEND_AF)
229 if (len <= sizeof(iph) || len > sizeof(rbuf) - 4)
231 /* Determine address family from packet IP header. */
232 memcpy(&iph, buf, sizeof(iph));
233 af = iph.ip_v == 6 ? OPENBSD_AF_INET6 : OPENBSD_AF_INET;
234 /* Prepend address family to packet using OpenBSD constants */
235 memcpy(rbuf + 4, buf, len);
239 #elif defined(SSH_TUN_COMPAT_AF)
240 /* Convert existing address family header to OpenBSD value */
245 POKE_U32(buf, af == AF_INET6 ? OPENBSD_AF_INET6 : OPENBSD_AF_INET);
248 if ((r = sshbuf_put_string(c->input, ptr, len)) != 0)
249 fatal("%s: buffer error: %s", __func__, ssh_err(r));
254 sys_tun_outfilter(struct ssh *ssh, struct Channel *c,
255 u_char **data, size_t *dlen)
261 /* XXX new API is incompatible with this signature. */
262 if ((r = sshbuf_get_string(c->output, data, dlen)) != 0)
263 fatal("%s: buffer error: %s", __func__, ssh_err(r));
264 if (*dlen < sizeof(af))
268 #if defined(SSH_TUN_PREPEND_AF)
269 /* skip address family */
271 buf = *data + sizeof(af);
272 #elif defined(SSH_TUN_COMPAT_AF)
273 /* translate address family */
274 af = (PEEK_U32(buf) == OPENBSD_AF_INET6) ? AF_INET6 : AF_INET;
279 #endif /* SSH_TUN_FILTER */