/* * Copyright (c) 1996, Nickolay Dudorov * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice unmodified, this list of conditions, and the following * disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD: src/sbin/nos-tun/nos-tun.c,v 1.6.2.2 2001/08/01 23:14:00 obrien Exp $ */ /* * 'nos-tun' program configure tunN interface as a point-to-point * connection with two "pseudo"-addresses between this host and * 'target'. * * It uses Ip-over-Ip incapsulation ( protocol number 94 - IPIP) * (known as NOS-incapsulation in CISCO-routers' terminology). * * 'nos-tun' can works with itself and CISCO-routers. * (It may also work with Linux 'nos-tun's, but * I have no Linux system here to test with). * * BUGS (or features ?): * - you must specify ONE of the target host's addresses * ( nos-tun sends and accepts packets only to/from this * address ) * - there can be only ONE tunnel between two hosts, * more precisely - between given host and (one of) * target hosts' address(es) * (and why do you want more ?) */ /* * Mar. 23 1999 by Isao SEKI * I added a new flag for ip protocol number. * We are using 4 as protocol number in ampr.org. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Tunnel interface configuration stuff */ static struct ifaliasreq ifra; static struct ifreq ifrq; /* Tun(4) device autocloner */ static const char *tun_dev = "/dev/tun"; /* Global descriptors */ int net; /* socket descriptor */ int tun; /* tunnel descriptor */ static void usage(void); static int Set_address(char *addr, struct sockaddr_in *my_sin) { struct hostent *hp; bzero(my_sin, sizeof(struct sockaddr)); my_sin->sin_family = AF_INET; if((my_sin->sin_addr.s_addr = inet_addr(addr)) == (in_addr_t)-1) { hp = gethostbyname(addr); if (!hp) { syslog(LOG_ERR,"unknown host %s", addr); return 1; } my_sin->sin_family = hp->h_addrtype; bcopy(hp->h_addr, (caddr_t)&my_sin->sin_addr, hp->h_length); } return 0; } static int tun_open(struct sockaddr *ouraddr, char *theiraddr) { int s; struct sockaddr_in *my_sin; /* Open tun device */ tun = open(tun_dev, O_RDWR); if (tun < 0) { syslog(LOG_ERR,"can't open %s - %m",tun_dev); return(1); } /* * At first, name the interface. */ bzero((char *)&ifra, sizeof(ifra)); bzero((char *)&ifrq, sizeof(ifrq)); if (ioctl(tun, TUNGIFNAME, &ifrq) < 0) { syslog(LOG_ERR,"can't get tun interface name - %m"); goto tunc_return; } strlcpy(ifra.ifra_name, ifrq.ifr_name, IFNAMSIZ); s = socket(AF_INET, SOCK_DGRAM, 0); if (s < 0) { syslog(LOG_ERR,"can't open socket - %m"); goto tunc_return; } /* * Delete (previous) addresses for interface * * !!!! * On FreeBSD this ioctl returns error * when tunN have no addresses, so - log and ignore it. */ if (ioctl(s, SIOCDIFADDR, &ifra) < 0) { syslog(LOG_ERR,"SIOCDIFADDR - %m"); } /* * Set interface address */ my_sin = (struct sockaddr_in *)&(ifra.ifra_addr); bcopy(ouraddr, my_sin, sizeof(struct sockaddr_in)); my_sin->sin_len = sizeof(*my_sin); /* * Set destination address */ my_sin = (struct sockaddr_in *)&(ifra.ifra_broadaddr); if (Set_address(theiraddr, my_sin)) { syslog(LOG_ERR,"bad destination address: %s",theiraddr); goto stunc_return; } my_sin->sin_len = sizeof(*my_sin); if (ioctl(s, SIOCAIFADDR, &ifra) < 0) { syslog(LOG_ERR,"can't set interface address - %m"); goto stunc_return; } /* * Now, bring up the interface. */ if (ioctl(s, SIOCGIFFLAGS, &ifrq) < 0) { syslog(LOG_ERR,"can't get interface flags - %m"); goto stunc_return; } ifrq.ifr_flags |= IFF_UP; if (!(ioctl(s, SIOCSIFFLAGS, &ifrq) < 0)) { close(s); return(0); } syslog(LOG_ERR,"can't set interface UP - %m"); stunc_return: close(s); tunc_return: close(tun); return(1); } static void Finish(int signum) { int s; syslog(LOG_INFO,"exiting"); close(net); s = socket(AF_INET, SOCK_DGRAM, 0); if (s < 0) { syslog(LOG_ERR,"can't open socket - %m"); goto closing_tun; } /* * Shut down interface. */ if (ioctl(s, SIOCGIFFLAGS, &ifrq) < 0) { syslog(LOG_ERR,"can't get interface flags - %m"); goto closing_fds; } ifrq.ifr_flags &= ~(IFF_UP|IFF_RUNNING); if (ioctl(s, SIOCSIFFLAGS, &ifrq) < 0) { syslog(LOG_ERR,"can't set interface DOWN - %m"); goto closing_fds; } /* * Delete addresses for interface */ bzero(&ifra.ifra_addr, sizeof(ifra.ifra_addr)); bzero(&ifra.ifra_broadaddr, sizeof(ifra.ifra_addr)); bzero(&ifra.ifra_mask, sizeof(ifra.ifra_addr)); if (ioctl(s, SIOCDIFADDR, &ifra) < 0) { syslog(LOG_ERR,"can't delete interface's addresses - %m"); } closing_fds: close(s); closing_tun: close(tun); closelog(); exit(signum); } int main(int argc, char **argv) { int c, len, ipoff; char *point_to = NULL; char *to_point = NULL; char *target; char *protocol = NULL; int protnum; struct sockaddr t_laddr; /* Source address of tunnel */ struct sockaddr whereto; /* Destination of tunnel */ struct sockaddr_in *to; char buf[0x2000]; /* Packets buffer */ struct ip *ip = (struct ip *)buf; fd_set rfds, wfds, efds; /* File descriptors for select() */ int nfds; /* Return from select() */ while ((c = getopt(argc, argv, "d:s:p:")) != -1) { switch (c) { case 'd': to_point = optarg; break; case 's': point_to = optarg; break; case 'p': protocol = optarg; break; } } argc -= optind; argv += optind; if (argc != 1 || (point_to == NULL) || (to_point == NULL)) usage(); if(protocol == NULL) protnum = 94; else protnum = atoi(protocol); target = *argv; /* Establish logging through 'syslog' */ openlog("nos-tun", LOG_PID, LOG_DAEMON); if(Set_address(point_to, (struct sockaddr_in *)&t_laddr)) { closelog(); exit(2); } if(tun_open(&t_laddr, to_point)) { closelog(); exit(3); } to = (struct sockaddr_in *)&whereto; if(Set_address(target, to)) Finish(4); if ((net = socket(AF_INET, SOCK_RAW, protnum)) < 0) { syslog(LOG_ERR,"can't open socket - %m"); Finish(5); } if (connect(net,&whereto,sizeof(struct sockaddr_in)) < 0 ) { syslog(LOG_ERR,"can't connect to target - %m"); close(net); Finish(6); } /* Demonize it */ daemon(0,0); /* Install signal handlers */ signal(SIGHUP,Finish); signal(SIGINT,Finish); signal(SIGTERM,Finish); for (;;) { /* Set file descriptors for select() */ FD_ZERO(&rfds); FD_ZERO(&wfds); FD_ZERO(&efds); FD_SET(tun,&rfds); FD_SET(net,&rfds); nfds = select(net+10,&rfds,&wfds,&efds,NULL); if(nfds < 0) { syslog(LOG_ERR,"interrupted select"); close(net); Finish(7); } if(nfds == 0) { /* Impossible ? */ syslog(LOG_ERR,"timeout in select"); close(net); Finish(8); } if(FD_ISSET(net,&rfds)) { /* Read from socket ... */ len = read(net, buf, sizeof(buf)); /* Check if this is "our" packet */ if((ip->ip_src).s_addr == (to->sin_addr).s_addr) { /* ... skip encapsulation headers ... */ ipoff = (ip->ip_hl << 2); /* ... and write to tun-device */ write(tun,buf+ipoff,len-ipoff); } } if(FD_ISSET(tun,&rfds)) { /* Read from tun ... */ len = read(tun, buf, sizeof(buf)); /* ... and send to network */ if(send(net, buf, len,0) <= 0) { syslog(LOG_ERR,"can't send - %m"); } } } } static void usage(void) { fprintf(stderr, "usage: nos-tun -s -d " "-p \n"); exit(1); }