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/ioctl.h>
20 #include <netinet/ip.h>
27 * This is the portable version of the SSH tunnel forwarding, it
28 * uses some preprocessor definitions for various platform-specific
31 * SSH_TUN_LINUX Use the (newer) Linux tun/tap device
32 * SSH_TUN_COMPAT_AF Translate the OpenBSD address family
33 * SSH_TUN_PREPEND_AF Prepend/remove the address family
37 * System-specific tunnel open function
40 #if defined(SSH_TUN_LINUX)
42 #include <linux/if_tun.h>
45 sys_tun_open(int tun, int mode)
49 const char *name = NULL;
51 if ((fd = open("/dev/net/tun", O_RDWR)) == -1) {
52 debug("%s: failed to open tunnel control interface: %s",
53 __func__, strerror(errno));
57 bzero(&ifr, sizeof(ifr));
59 if (mode == SSH_TUNMODE_ETHERNET) {
60 ifr.ifr_flags = IFF_TAP;
63 ifr.ifr_flags = IFF_TUN;
66 ifr.ifr_flags |= IFF_NO_PI;
68 if (tun != SSH_TUNID_ANY) {
69 if (tun > SSH_TUNID_MAX) {
70 debug("%s: invalid tunnel id %x: %s", __func__,
71 tun, strerror(errno));
74 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), name, tun);
77 if (ioctl(fd, TUNSETIFF, &ifr) == -1) {
78 debug("%s: failed to configure tunnel (mode %d): %s", __func__,
79 mode, strerror(errno));
83 if (tun == SSH_TUNID_ANY)
84 debug("%s: tunnel mode %d fd %d", __func__, mode, fd);
86 debug("%s: %s mode %d fd %d", __func__, ifr.ifr_name, mode, fd);
94 #endif /* SSH_TUN_LINUX */
96 #ifdef SSH_TUN_FREEBSD
97 #include <sys/socket.h>
99 #include <net/if_tun.h>
102 sys_tun_open(int tun, int mode)
106 int fd = -1, sock, flag;
107 const char *tunbase = "tun";
109 if (mode == SSH_TUNMODE_ETHERNET) {
111 debug("%s: no layer 2 tunnelling support", __func__);
118 /* Open the tunnel device */
119 if (tun <= SSH_TUNID_MAX) {
120 snprintf(name, sizeof(name), "/dev/%s%d", tunbase, tun);
121 fd = open(name, O_RDWR);
122 } else if (tun == SSH_TUNID_ANY) {
123 for (tun = 100; tun >= 0; tun--) {
124 snprintf(name, sizeof(name), "/dev/%s%d",
126 if ((fd = open(name, O_RDWR)) >= 0)
130 debug("%s: invalid tunnel %u\n", __func__, tun);
135 debug("%s: %s open failed: %s", __func__, name,
140 /* Turn on tunnel headers */
142 #if defined(TUNSIFHEAD) && !defined(SSH_TUN_PREPEND_AF)
143 if (mode != SSH_TUNMODE_ETHERNET &&
144 ioctl(fd, TUNSIFHEAD, &flag) == -1) {
145 debug("%s: ioctl(%d, TUNSIFHEAD, 1): %s", __func__, fd,
151 debug("%s: %s mode %d fd %d", __func__, name, mode, fd);
153 /* Set the tunnel device operation mode */
154 snprintf(ifr.ifr_name, sizeof(ifr.ifr_name), "%s%d", tunbase, tun);
155 if ((sock = socket(PF_UNIX, SOCK_STREAM, 0)) == -1)
158 if (ioctl(sock, SIOCGIFFLAGS, &ifr) == -1)
160 ifr.ifr_flags |= IFF_UP;
161 if (ioctl(sock, SIOCSIFFLAGS, &ifr) == -1)
172 debug("%s: failed to set %s mode %d: %s", __func__, name,
173 mode, strerror(errno));
176 #endif /* SSH_TUN_FREEBSD */
179 * System-specific channel filters
182 #if defined(SSH_TUN_FILTER)
183 #define OPENBSD_AF_INET 2
184 #define OPENBSD_AF_INET6 24
187 sys_tun_infilter(struct Channel *c, char *buf, int len)
189 #if defined(SSH_TUN_PREPEND_AF)
190 char rbuf[CHAN_RBUF];
196 #if defined(SSH_TUN_PREPEND_AF)
197 if (len <= 0 || len > (int)(sizeof(rbuf) - sizeof(*af)))
199 ptr = (char *)&rbuf[0];
200 bcopy(buf, ptr + sizeof(u_int32_t), len);
201 len += sizeof(u_int32_t);
202 af = (u_int32_t *)ptr;
204 iph = (struct ip *)(ptr + sizeof(u_int32_t));
216 #if defined(SSH_TUN_COMPAT_AF)
217 if (len < (int)sizeof(u_int32_t))
220 af = (u_int32_t *)ptr;
221 if (*af == htonl(AF_INET6))
222 *af = htonl(OPENBSD_AF_INET6);
224 *af = htonl(OPENBSD_AF_INET);
227 buffer_put_string(&c->input, ptr, len);
232 sys_tun_outfilter(struct Channel *c, u_char **data, u_int *dlen)
237 *data = buffer_get_string(&c->output, dlen);
238 if (*dlen < sizeof(*af))
242 #if defined(SSH_TUN_PREPEND_AF)
243 *dlen -= sizeof(u_int32_t);
244 buf = *data + sizeof(u_int32_t);
245 #elif defined(SSH_TUN_COMPAT_AF)
246 af = ntohl(*(u_int32_t *)buf);
247 if (*af == OPENBSD_AF_INET6)
248 *af = htonl(AF_INET6);
250 *af = htonl(AF_INET);
255 #endif /* SSH_TUN_FILTER */