2 * Copyright (c) 1996, Nickolay Dudorov
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice unmodified, this list of conditions, and the following
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * $FreeBSD: src/sbin/nos-tun/nos-tun.c,v 1.6.2.2 2001/08/01 23:14:00 obrien Exp $
28 * $DragonFly: src/sbin/nos-tun/nos-tun.c,v 1.4 2003/11/01 17:16:01 drhodus Exp $
32 * 'nos-tun' program configure tunN interface as a point-to-point
33 * connection with two "pseudo"-addresses between this host and
36 * It uses Ip-over-Ip incapsulation ( protocol number 94 - IPIP)
37 * (known as NOS-incapsulation in CISCO-routers' terminology).
39 * 'nos-tun' can works with itself and CISCO-routers.
40 * (It may also work with Linux 'nos-tun's, but
41 * I have no Linux system here to test with).
43 * BUGS (or features ?):
44 * - you must specify ONE of the target host's addresses
45 * ( nos-tun sends and accepts packets only to/from this
47 * - there can be only ONE tunnel between two hosts,
48 * more precisely - between given host and (one of)
49 * target hosts' address(es)
50 * (and why do you want more ?)
54 * Mar. 23 1999 by Isao SEKI <iseki@gongon.com>
55 * I added a new flag for ip protocol number.
56 * We are using 4 as protocol number in ampr.org.
66 #include <sys/signal.h>
67 #include <sys/socket.h>
68 #include <sys/ioctl.h>
69 #include <netinet/in.h>
70 #include <netinet/in_systm.h>
71 #include <netinet/ip.h>
73 #include <arpa/inet.h>
76 /* Tunnel interface configuration stuff */
77 static struct ifaliasreq ifra;
78 static struct ifreq ifrq;
80 /* Global descriptors */
81 int net; /* socket descriptor */
82 int tun; /* tunnel descriptor */
84 static void usage(void);
86 int Set_address(char *addr, struct sockaddr_in *sin)
90 bzero((char *)sin, sizeof(struct sockaddr));
91 sin->sin_family = AF_INET;
92 if((sin->sin_addr.s_addr = inet_addr(addr)) == (u_long)-1) {
93 hp = gethostbyname(addr);
95 syslog(LOG_ERR,"unknown host %s", addr);
98 sin->sin_family = hp->h_addrtype;
99 bcopy(hp->h_addr, (caddr_t)&sin->sin_addr, hp->h_length);
104 int tun_open(char *devname, struct sockaddr *ouraddr, char *theiraddr)
107 struct sockaddr_in *sin;
109 /* Open tun device */
110 tun = open (devname, O_RDWR);
112 syslog(LOG_ERR,"can't open %s - %m",devname);
117 * At first, name the interface.
119 bzero((char *)&ifra, sizeof(ifra));
120 bzero((char *)&ifrq, sizeof(ifrq));
122 strncpy(ifrq.ifr_name, devname+5, IFNAMSIZ);
123 strncpy(ifra.ifra_name, devname+5, IFNAMSIZ);
125 s = socket(AF_INET, SOCK_DGRAM, 0);
127 syslog(LOG_ERR,"can't open socket - %m");
132 * Delete (previous) addresses for interface
135 * On FreeBSD this ioctl returns error
136 * when tunN have no addresses, so - log and ignore it.
139 if (ioctl(s, SIOCDIFADDR, &ifra) < 0) {
140 syslog(LOG_ERR,"SIOCDIFADDR - %m");
144 * Set interface address
146 sin = (struct sockaddr_in *)&(ifra.ifra_addr);
147 bcopy(ouraddr, sin, sizeof(struct sockaddr_in));
148 sin->sin_len = sizeof(*sin);
151 * Set destination address
153 sin = (struct sockaddr_in *)&(ifra.ifra_broadaddr);
154 if(Set_address(theiraddr,sin)) {
155 syslog(LOG_ERR,"bad destination address: %s",theiraddr);
158 sin->sin_len = sizeof(*sin);
160 if (ioctl(s, SIOCAIFADDR, &ifra) < 0) {
161 syslog(LOG_ERR,"can't set interface address - %m");
166 * Now, bring up the interface.
168 if (ioctl(s, SIOCGIFFLAGS, &ifrq) < 0) {
169 syslog(LOG_ERR,"can't get interface flags - %m");
173 ifrq.ifr_flags |= IFF_UP;
174 if (!(ioctl(s, SIOCSIFFLAGS, &ifrq) < 0)) {
178 syslog(LOG_ERR,"can't set interface UP - %m");
186 void Finish(int signum)
190 syslog(LOG_INFO,"exiting");
194 s = socket(AF_INET, SOCK_DGRAM, 0);
196 syslog(LOG_ERR,"can't open socket - %m");
201 * Shut down interface.
203 if (ioctl(s, SIOCGIFFLAGS, &ifrq) < 0) {
204 syslog(LOG_ERR,"can't get interface flags - %m");
208 ifrq.ifr_flags &= ~(IFF_UP|IFF_RUNNING);
209 if (ioctl(s, SIOCSIFFLAGS, &ifrq) < 0) {
210 syslog(LOG_ERR,"can't set interface DOWN - %m");
215 * Delete addresses for interface
217 bzero(&ifra.ifra_addr, sizeof(ifra.ifra_addr));
218 bzero(&ifra.ifra_broadaddr, sizeof(ifra.ifra_addr));
219 bzero(&ifra.ifra_mask, sizeof(ifra.ifra_addr));
220 if (ioctl(s, SIOCDIFADDR, &ifra) < 0) {
221 syslog(LOG_ERR,"can't delete interface's addresses - %m");
231 int main (int argc, char **argv)
235 char *devname = NULL;
236 char *point_to = NULL;
237 char *to_point = NULL;
239 char *protocol = NULL;
242 struct sockaddr t_laddr; /* Source address of tunnel */
243 struct sockaddr whereto; /* Destination of tunnel */
244 struct sockaddr_in *to;
246 char buf[0x2000]; /* Packets buffer */
247 struct ip *ip = (struct ip *)buf;
249 fd_set rfds, wfds, efds; /* File descriptors for select() */
250 int nfds; /* Return from select() */
253 while ((c = getopt(argc, argv, "d:s:t:p:")) != -1) {
272 if (argc != 1 || (devname == NULL) ||
273 (point_to == NULL) || (to_point == NULL)) {
280 protnum = atoi(protocol);
284 /* Establish logging through 'syslog' */
285 openlog("nos-tun", LOG_PID, LOG_DAEMON);
287 if(Set_address(point_to, (struct sockaddr_in *)&t_laddr)) {
292 if(tun_open(devname, &t_laddr, to_point)) {
297 to = (struct sockaddr_in *)&whereto;
298 if(Set_address(target, to))
301 if ((net = socket(AF_INET, SOCK_RAW, protnum)) < 0) {
302 syslog(LOG_ERR,"can't open socket - %m");
306 if (connect(net,&whereto,sizeof(struct sockaddr_in)) < 0 ) {
307 syslog(LOG_ERR,"can't connect to target - %m");
315 /* Install signal handlers */
316 (void)signal(SIGHUP,Finish);
317 (void)signal(SIGINT,Finish);
318 (void)signal(SIGTERM,Finish);
321 /* Set file descriptors for select() */
322 FD_ZERO(&rfds); FD_ZERO(&wfds); FD_ZERO(&efds);
323 FD_SET(tun,&rfds); FD_SET(net,&rfds);
325 nfds = select(net+10,&rfds,&wfds,&efds,NULL);
327 syslog(LOG_ERR,"interrupted select");
331 if(nfds == 0) { /* Impossible ? */
332 syslog(LOG_ERR,"timeout in select");
338 if(FD_ISSET(net,&rfds)) {
339 /* Read from socket ... */
340 len = read(net, buf, sizeof(buf));
341 /* Check if this is "our" packet */
342 if((ip->ip_src).s_addr == (to->sin_addr).s_addr) {
343 /* ... skip encapsulation headers ... */
344 ipoff = (ip->ip_hl << 2);
345 /* ... and write to tun-device */
346 write(tun,buf+ipoff,len-ipoff);
350 if(FD_ISSET(tun,&rfds)) {
351 /* Read from tun ... */
352 len = read(tun, buf, sizeof(buf));
353 /* ... and send to network */
354 if(send(net, buf, len,0) <= 0) {
355 syslog(LOG_ERR,"can't send - %m");
365 "usage: nos-tun -t <tun_name> -s <source_addr> -d <dest_addr> -p <protocol_number> <target_addr>\n");