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>
38 * This is the portable version of the SSH tunnel forwarding, it
39 * uses some preprocessor definitions for various platform-specific
42 * SSH_TUN_LINUX Use the (newer) Linux tun/tap device
43 * SSH_TUN_FREEBSD Use the FreeBSD tun/tap device
44 * SSH_TUN_COMPAT_AF Translate the OpenBSD address family
45 * SSH_TUN_PREPEND_AF Prepend/remove the address family
49 * System-specific tunnel open function
52 #if defined(SSH_TUN_LINUX)
54 #include <linux/if_tun.h>
57 sys_tun_open(int tun, int mode)
61 const char *name = NULL;
63 if ((fd = open("/dev/net/tun", O_RDWR)) == -1) {
64 debug("%s: failed to open tunnel control interface: %s",
65 __func__, strerror(errno));
69 bzero(&ifr, sizeof(ifr));
71 if (mode == SSH_TUNMODE_ETHERNET) {
72 ifr.ifr_flags = IFF_TAP;
75 ifr.ifr_flags = IFF_TUN;
78 ifr.ifr_flags |= IFF_NO_PI;
80 if (tun != SSH_TUNID_ANY) {
81 if (tun > SSH_TUNID_MAX) {
82 debug("%s: invalid tunnel id %x: %s", __func__,
83 tun, strerror(errno));
86 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), name, tun);
89 if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
90 debug("%s: failed to configure tunnel (mode %d): %s", __func__,
91 mode, strerror(errno));
95 if (tun == SSH_TUNID_ANY)
96 debug("%s: tunnel mode %d fd %d", __func__, mode, fd);
98 debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd);
106 #endif /* SSH_TUN_LINUX */
108 #ifdef SSH_TUN_FREEBSD
109 #include <sys/socket.h>
112 #ifdef HAVE_NET_IF_TUN_H
113 #include <net/tun/if_tun.h>
117 sys_tun_open(int tun, int mode)
121 int fd = -1, sock, flag;
122 const char *tunbase = "tun";
124 if (mode == SSH_TUNMODE_ETHERNET) {
126 debug("%s: no layer 2 tunnelling support", __func__);
133 /* Open the tunnel device */
134 if (tun <= SSH_TUNID_MAX) {
135 snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
136 fd = open(name, O_RDWR);
137 } else if (tun == SSH_TUNID_ANY) {
138 for (tun = 100; tun >= 0; tun--) {
139 snprintf(name, sizeof(name), "/dev/%s%d",
141 if ((fd = open(name, O_RDWR)) >= 0)
145 debug("%s: invalid tunnel %u\n", __func__, tun);
150 debug("%s: %s open failed: %s", __func__, name,
155 /* Turn on tunnel headers */
157 #if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF)
158 if (mode != SSH_TUNMODE_ETHERNET &&
159 ioctl(fd, TUNSIFHEAD, &flag) == -1) {
160 debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd,
166 debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
168 /* Set the tunnel device operation mode */
169 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
170 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
173 if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
175 ifr.ifr_flags |= IFF_UP;
176 if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
187 debug("%s: failed to set %s mode %d: %s", __func__, name,
188 mode, strerror(errno));
191 #endif /* SSH_TUN_FREEBSD */
194 * System-specific channel filters
197 #if defined(SSH_TUN_FILTER)
198 #define OPENBSD_AF_INET 2
199 #define OPENBSD_AF_INET6 24
202 sys_tun_infilter(struct Channel *c, char *buf, int len)
204 #if defined(SSH_TUN_PREPEND_AF)
205 char rbuf[CHAN_RBUF];
211 #if defined(SSH_TUN_PREPEND_AF)
212 if (len <= 0 || len > (int)(sizeof(rbuf) - sizeof(*af)))
214 ptr = (char *)&rbuf[0];
215 bcopy(buf, ptr + sizeof(u_int32_t), len);
216 len += sizeof(u_int32_t);
217 af = (u_int32_t *)ptr;
219 iph = (struct ip *)(ptr + sizeof(u_int32_t));
231 #if defined(SSH_TUN_COMPAT_AF)
232 if (len < (int)sizeof(u_int32_t))
235 af = (u_int32_t *)ptr;
236 if (*af == htonl(AF_INET6))
237 *af = htonl(OPENBSD_AF_INET6);
239 *af = htonl(OPENBSD_AF_INET);
242 buffer_put_string(&c->input, ptr, len);
247 sys_tun_outfilter(struct Channel *c, u_char **data, u_int *dlen)
252 *data = buffer_get_string(&c->output, dlen);
253 if (*dlen < sizeof(*af))
257 #if defined(SSH_TUN_PREPEND_AF)
258 *dlen -= sizeof(u_int32_t);
259 buf = *data + sizeof(u_int32_t);
260 #elif defined(SSH_TUN_COMPAT_AF)
261 af = ntohl(*(u_int32_t *)buf);
262 if (*af == OPENBSD_AF_INET6)
263 *af = htonl(AF_INET6);
265 *af = htonl(AF_INET);
270 #endif /* SSH_TUN_FILTER */