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.
24 * This is the portable version of the SSH tunnel forwarding, it
25 * uses some preprocessor definitions for various platform-specific
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
34 * System-specific tunnel open function
37 #if defined(SSH_TUN_LINUX)
39 #include <linux/if_tun.h>
42 sys_tun_open(int tun, int mode)
46 const char *name = NULL;
48 if ((fd = open("/dev/net/tun", O_RDWR)) == -1) {
49 debug("%s: failed to open tunnel control interface: %s",
50 __func__, strerror(errno));
54 bzero(&ifr, sizeof(ifr));
56 if (mode == SSH_TUNMODE_ETHERNET) {
57 ifr.ifr_flags = IFF_TAP;
60 ifr.ifr_flags = IFF_TUN;
63 ifr.ifr_flags |= IFF_NO_PI;
65 if (tun != SSH_TUNID_ANY) {
66 if (tun > SSH_TUNID_MAX) {
67 debug("%s: invalid tunnel id %x: %s", __func__,
68 tun, strerror(errno));
71 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), name, tun);
74 if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
75 debug("%s: failed to configure tunnel (mode %d): %s", __func__,
76 mode, strerror(errno));
80 if (tun == SSH_TUNID_ANY)
81 debug("%s: tunnel mode %d fd %d", __func__, mode, fd);
83 debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd);
91 #endif /* SSH_TUN_LINUX */
93 #ifdef SSH_TUN_FREEBSD
94 #include <sys/socket.h>
96 #include <net/if_tun.h>
99 sys_tun_open(int tun, int mode)
103 int fd = -1, sock, flag;
104 const char *tunbase = "tun";
106 if (mode == SSH_TUNMODE_ETHERNET) {
108 debug("%s: no layer 2 tunnelling support", __func__);
115 /* Open the tunnel device */
116 if (tun <= SSH_TUNID_MAX) {
117 snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
118 fd = open(name, O_RDWR);
119 } else if (tun == SSH_TUNID_ANY) {
120 for (tun = 100; tun >= 0; tun--) {
121 snprintf(name, sizeof(name), "/dev/%s%d",
123 if ((fd = open(name, O_RDWR)) >= 0)
127 debug("%s: invalid tunnel %u\n", __func__, tun);
132 debug("%s: %s open failed: %s", __func__, name,
137 /* Turn on tunnel headers */
139 #if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF)
140 if (mode != SSH_TUNMODE_ETHERNET &&
141 ioctl(fd, TUNSIFHEAD, &flag) == -1) {
142 debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd,
148 debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
150 /* Set the tunnel device operation mode */
151 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
152 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
155 if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
157 ifr.ifr_flags |= IFF_UP;
158 if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
169 debug("%s: failed to set %s mode %d: %s", __func__, name,
170 mode, strerror(errno));
173 #endif /* SSH_TUN_FREEBSD */
176 * System-specific channel filters
179 #if defined(SSH_TUN_FILTER)
180 #define OPENBSD_AF_INET 2
181 #define OPENBSD_AF_INET6 24
184 sys_tun_infilter(struct Channel *c, char *buf, int len)
186 #if defined(SSH_TUN_PREPEND_AF)
187 char rbuf[CHAN_RBUF];
193 #if defined(SSH_TUN_PREPEND_AF)
194 if (len <= 0 || len > (int)(sizeof(rbuf) - sizeof(*af)))
196 ptr = (char *)&rbuf[0];
197 bcopy(buf, ptr + sizeof(u_int32_t), len);
198 len += sizeof(u_int32_t);
199 af = (u_int32_t *)ptr;
201 iph = (struct ip *)(ptr + sizeof(u_int32_t));
213 #if defined(SSH_TUN_COMPAT_AF)
214 if (len < (int)sizeof(u_int32_t))
217 af = (u_int32_t *)ptr;
218 if (*af == htonl(AF_INET6))
219 *af = htonl(OPENBSD_AF_INET6);
221 *af = htonl(OPENBSD_AF_INET);
224 buffer_put_string(&c->input, ptr, len);
229 sys_tun_outfilter(struct Channel *c, u_char **data, u_int *dlen)
234 *data = buffer_get_string(&c->output, dlen);
235 if (*dlen < sizeof(*af))
239 #if defined(SSH_TUN_PREPEND_AF)
240 *dlen -= sizeof(u_int32_t);
241 buf = *data + sizeof(u_int32_t);
242 #elif defined(SSH_TUN_COMPAT_AF)
243 af = ntohl(*(u_int32_t *)buf);
244 if (*af == OPENBSD_AF_INET6)
245 *af = htonl(AF_INET6);
247 *af = htonl(AF_INET);
252 #endif /* SSH_TUN_FILTER */