135137Sphk/* 235137Sphk * Copyright (c) 1996, Nickolay Dudorov 335137Sphk * All rights reserved. 435137Sphk * 535137Sphk * Redistribution and use in source and binary forms, with or without 635137Sphk * modification, are permitted provided that the following conditions 735137Sphk * are met: 835137Sphk * 1. Redistributions of source code must retain the above copyright 935137Sphk * notice unmodified, this list of conditions, and the following 1035137Sphk * disclaimer. 1135137Sphk * 2. Redistributions in binary form must reproduce the above copyright 1235137Sphk * notice, this list of conditions and the following disclaimer in the 1335137Sphk * documentation and/or other materials provided with the distribution. 1435137Sphk * 1535137Sphk * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1635137Sphk * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1735137Sphk * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1835137Sphk * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 1935137Sphk * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2035137Sphk * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2135137Sphk * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2235137Sphk * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2335137Sphk * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 2435137Sphk * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 2535137Sphk * SUCH DAMAGE. 2635137Sphk * 2735137Sphk */ 2835137Sphk 2935137Sphk/* 3061438Sasmodai * 'nos-tun' program configure tunN interface as a point-to-point 3135137Sphk * connection with two "pseudo"-addresses between this host and 3235137Sphk * 'target'. 3335137Sphk * 3435137Sphk * It uses Ip-over-Ip incapsulation ( protocol number 94 - IPIP) 3535137Sphk * (known as NOS-incapsulation in CISCO-routers' terminology). 3635137Sphk * 3761438Sasmodai * 'nos-tun' can works with itself and CISCO-routers. 3861438Sasmodai * (It may also work with Linux 'nos-tun's, but 3935137Sphk * I have no Linux system here to test with). 4035137Sphk * 4135137Sphk * BUGS (or features ?): 4235137Sphk * - you must specify ONE of the target host's addresses 4361438Sasmodai * ( nos-tun sends and accepts packets only to/from this 4435137Sphk * address ) 4535137Sphk * - there can be only ONE tunnel between two hosts, 4635137Sphk * more precisely - between given host and (one of) 4735137Sphk * target hosts' address(es) 4835137Sphk * (and why do you want more ?) 4935137Sphk */ 5035137Sphk 5145114Sphk/* 5245114Sphk * Mar. 23 1999 by Isao SEKI <iseki@gongon.com> 5345114Sphk * I added a new flag for ip protocol number. 5445114Sphk * We are using 4 as protocol number in ampr.org. 5545114Sphk * 5645114Sphk */ 5745114Sphk 5837669Scharnier#ifndef lint 5937669Scharnierstatic const char rcsid[] = 6050476Speter "$FreeBSD$"; 6137669Scharnier#endif /* not lint */ 6235137Sphk 63103417Smike#include <sys/types.h> 64103417Smike#include <sys/ioctl.h> 65103417Smike#include <sys/signal.h> 66103417Smike#include <sys/socket.h> 67103417Smike 68103417Smike#include <net/if.h> 69103417Smike#include <netinet/in.h> 70103417Smike#include <netinet/in_systm.h> 71103417Smike#include <netinet/ip.h> 72103417Smike 73103417Smike#include <arpa/inet.h> 7435734Scharnier#include <fcntl.h> 7535734Scharnier#include <netdb.h> 7635137Sphk#include <stdio.h> 7735137Sphk#include <stdlib.h> 7835137Sphk#include <string.h> 7935137Sphk#include <syslog.h> 8035734Scharnier#include <unistd.h> 8135137Sphk 8235137Sphk/* Tunnel interface configuration stuff */ 8335137Sphkstatic struct ifaliasreq ifra; 8435137Sphkstatic struct ifreq ifrq; 8535137Sphk 8635137Sphk/* Global descriptors */ 8735137Sphkint net; /* socket descriptor */ 8835137Sphkint tun; /* tunnel descriptor */ 8935137Sphk 9092883Simpstatic void usage(void); 9135734Scharnier 92204966Suqsstatic int 93204966SuqsSet_address(char *addr, struct sockaddr_in *sin) 9435137Sphk{ 9535137Sphk struct hostent *hp; 9635137Sphk 9735137Sphk bzero((char *)sin, sizeof(struct sockaddr)); 9835137Sphk sin->sin_family = AF_INET; 99121540Speter if((sin->sin_addr.s_addr = inet_addr(addr)) == (in_addr_t)-1) { 10035137Sphk hp = gethostbyname(addr); 10135137Sphk if (!hp) { 10237669Scharnier syslog(LOG_ERR,"unknown host %s", addr); 10335137Sphk return 1; 10435137Sphk } 10535137Sphk sin->sin_family = hp->h_addrtype; 10635137Sphk bcopy(hp->h_addr, (caddr_t)&sin->sin_addr, hp->h_length); 10735137Sphk } 10835137Sphk return 0; 10935137Sphk} 11035137Sphk 111204966Suqsstatic int 112204966Suqstun_open(char *dev_name, struct sockaddr *ouraddr, char *theiraddr) 11335137Sphk{ 11435137Sphk int s; 11535137Sphk struct sockaddr_in *sin; 11635137Sphk 11735137Sphk /* Open tun device */ 118204966Suqs tun = open(dev_name, O_RDWR); 11935137Sphk if (tun < 0) { 120204966Suqs syslog(LOG_ERR,"can't open %s - %m", dev_name); 12135137Sphk return(1); 12235137Sphk } 12335137Sphk 12435137Sphk /* 12535137Sphk * At first, name the interface. 12635137Sphk */ 12735137Sphk bzero((char *)&ifra, sizeof(ifra)); 12835137Sphk bzero((char *)&ifrq, sizeof(ifrq)); 12935137Sphk 130204966Suqs strncpy(ifrq.ifr_name, dev_name+5, IFNAMSIZ); 131204966Suqs strncpy(ifra.ifra_name, dev_name+5, IFNAMSIZ); 13235137Sphk 13335137Sphk s = socket(AF_INET, SOCK_DGRAM, 0); 13435137Sphk if (s < 0) { 13538023Sbde syslog(LOG_ERR,"can't open socket - %m"); 13635137Sphk goto tunc_return; 13735137Sphk } 13835137Sphk 13935137Sphk /* 14080203Skris * Delete (previous) addresses for interface 14135137Sphk * 14235137Sphk * !!!! 14335137Sphk * On FreeBSD this ioctl returns error 14435137Sphk * when tunN have no addresses, so - log and ignore it. 14535137Sphk * 14635137Sphk */ 14735137Sphk if (ioctl(s, SIOCDIFADDR, &ifra) < 0) { 14835137Sphk syslog(LOG_ERR,"SIOCDIFADDR - %m"); 14935137Sphk } 15035137Sphk 15135137Sphk /* 15235137Sphk * Set interface address 15335137Sphk */ 15435137Sphk sin = (struct sockaddr_in *)&(ifra.ifra_addr); 15535137Sphk bcopy(ouraddr, sin, sizeof(struct sockaddr_in)); 15635137Sphk sin->sin_len = sizeof(*sin); 15735137Sphk 15835137Sphk /* 15935137Sphk * Set destination address 16035137Sphk */ 16135137Sphk sin = (struct sockaddr_in *)&(ifra.ifra_broadaddr); 16235137Sphk if(Set_address(theiraddr,sin)) { 16337669Scharnier syslog(LOG_ERR,"bad destination address: %s",theiraddr); 16435137Sphk goto stunc_return; 16535137Sphk } 16635137Sphk sin->sin_len = sizeof(*sin); 16735137Sphk 16835137Sphk if (ioctl(s, SIOCAIFADDR, &ifra) < 0) { 16937669Scharnier syslog(LOG_ERR,"can't set interface address - %m"); 17035137Sphk goto stunc_return; 17135137Sphk } 17235137Sphk 17335137Sphk /* 17435137Sphk * Now, bring up the interface. 17535137Sphk */ 17635137Sphk if (ioctl(s, SIOCGIFFLAGS, &ifrq) < 0) { 17737669Scharnier syslog(LOG_ERR,"can't get interface flags - %m"); 17835137Sphk goto stunc_return; 17935137Sphk } 18035137Sphk 18135137Sphk ifrq.ifr_flags |= IFF_UP; 18235137Sphk if (!(ioctl(s, SIOCSIFFLAGS, &ifrq) < 0)) { 18335137Sphk close(s); 18435137Sphk return(0); 18535137Sphk } 18637669Scharnier syslog(LOG_ERR,"can't set interface UP - %m"); 18735137Sphkstunc_return: 18835137Sphk close(s); 18935137Sphktunc_return: 19035137Sphk close(tun); 19135137Sphk return(1); 19235137Sphk} 19335137Sphk 194204966Suqsstatic void 195204966SuqsFinish(int signum) 19635137Sphk{ 19735137Sphk int s; 19835137Sphk 19937669Scharnier syslog(LOG_INFO,"exiting"); 20035137Sphk 20135137Sphk close(net); 20235137Sphk 20335137Sphk s = socket(AF_INET, SOCK_DGRAM, 0); 20435137Sphk if (s < 0) { 20537669Scharnier syslog(LOG_ERR,"can't open socket - %m"); 20635137Sphk goto closing_tun; 20735137Sphk } 20835137Sphk 20935137Sphk /* 21035137Sphk * Shut down interface. 21135137Sphk */ 21235137Sphk if (ioctl(s, SIOCGIFFLAGS, &ifrq) < 0) { 21337669Scharnier syslog(LOG_ERR,"can't get interface flags - %m"); 21435137Sphk goto closing_fds; 21535137Sphk } 21635137Sphk 21735137Sphk ifrq.ifr_flags &= ~(IFF_UP|IFF_RUNNING); 21835137Sphk if (ioctl(s, SIOCSIFFLAGS, &ifrq) < 0) { 21937669Scharnier syslog(LOG_ERR,"can't set interface DOWN - %m"); 22035137Sphk goto closing_fds; 22135137Sphk } 22235137Sphk 22335137Sphk /* 22480203Skris * Delete addresses for interface 22535137Sphk */ 22635137Sphk bzero(&ifra.ifra_addr, sizeof(ifra.ifra_addr)); 22735137Sphk bzero(&ifra.ifra_broadaddr, sizeof(ifra.ifra_addr)); 22835137Sphk bzero(&ifra.ifra_mask, sizeof(ifra.ifra_addr)); 22935137Sphk if (ioctl(s, SIOCDIFADDR, &ifra) < 0) { 23037669Scharnier syslog(LOG_ERR,"can't delete interface's addresses - %m"); 23135137Sphk } 23235137Sphkclosing_fds: 23335137Sphk close(s); 23435137Sphkclosing_tun: 23535137Sphk close(tun); 23635137Sphk closelog(); 23735137Sphk exit(signum); 23835137Sphk} 23935137Sphk 24035137Sphkint main (int argc, char **argv) 24135137Sphk{ 24235137Sphk int c, len, ipoff; 24335137Sphk 244204966Suqs char *dev_name = NULL; 24535137Sphk char *point_to = NULL; 24635137Sphk char *to_point = NULL; 24735137Sphk char *target; 24874948Sphk char *source = NULL; 24945114Sphk char *protocol = NULL; 25045114Sphk int protnum; 25135137Sphk 25235137Sphk struct sockaddr t_laddr; /* Source address of tunnel */ 25335137Sphk struct sockaddr whereto; /* Destination of tunnel */ 25474948Sphk struct sockaddr wherefrom; /* Source of tunnel */ 25535137Sphk struct sockaddr_in *to; 25635137Sphk 25735137Sphk char buf[0x2000]; /* Packets buffer */ 25835137Sphk struct ip *ip = (struct ip *)buf; 25935137Sphk 26089583Sbillf fd_set rfds; /* File descriptors for select() */ 26135137Sphk int nfds; /* Return from select() */ 26289583Sbillf int lastfd; /* highest fd we care about */ 26335137Sphk 26435137Sphk 26545114Sphk while ((c = getopt(argc, argv, "d:s:t:p:")) != -1) { 26635137Sphk switch (c) { 26735137Sphk case 'd': 26835137Sphk to_point = optarg; 26935137Sphk break; 27035137Sphk case 's': 27135137Sphk point_to = optarg; 27235137Sphk break; 27335137Sphk case 't': 274204966Suqs dev_name = optarg; 27535137Sphk break; 27645114Sphk case 'p': 27745114Sphk protocol = optarg; 27845114Sphk break; 27935137Sphk } 28035137Sphk } 28135137Sphk argc -= optind; 28235137Sphk argv += optind; 28335137Sphk 284204966Suqs if ((argc != 1 && argc != 2) || (dev_name == NULL) || 28535137Sphk (point_to == NULL) || (to_point == NULL)) { 28635734Scharnier usage(); 28735137Sphk } 28835137Sphk 28945114Sphk if(protocol == NULL) 29045114Sphk protnum = 94; 29145114Sphk else 29245114Sphk protnum = atoi(protocol); 29345114Sphk 29474948Sphk if (argc == 1) { 29574948Sphk target = *argv; 29674948Sphk } else { 29774948Sphk source = *argv++; target = *argv; 29874948Sphk } 29935137Sphk 30035137Sphk /* Establish logging through 'syslog' */ 30161438Sasmodai openlog("nos-tun", LOG_PID, LOG_DAEMON); 30235137Sphk 30335137Sphk if(Set_address(point_to, (struct sockaddr_in *)&t_laddr)) { 30435137Sphk closelog(); 30535137Sphk exit(2); 30635137Sphk } 30735137Sphk 308204966Suqs if(tun_open(dev_name, &t_laddr, to_point)) { 30935137Sphk closelog(); 31035137Sphk exit(3); 31135137Sphk } 31235137Sphk 31335137Sphk to = (struct sockaddr_in *)&whereto; 31435137Sphk if(Set_address(target, to)) 31535137Sphk Finish(4); 31635137Sphk 31745114Sphk if ((net = socket(AF_INET, SOCK_RAW, protnum)) < 0) { 31837669Scharnier syslog(LOG_ERR,"can't open socket - %m"); 31935137Sphk Finish(5); 32035137Sphk } 32135137Sphk 32274948Sphk if (source) { 32374948Sphk if (Set_address(source, (struct sockaddr_in *)&wherefrom)) 32474948Sphk Finish(9); 32574948Sphk if (bind(net, &wherefrom, sizeof(wherefrom)) < 0) { 32674948Sphk syslog(LOG_ERR, "can't bind source address - %m"); 32774948Sphk Finish(10); 32874948Sphk } 32974948Sphk } 33074948Sphk 33135137Sphk if (connect(net,&whereto,sizeof(struct sockaddr_in)) < 0 ) { 33237669Scharnier syslog(LOG_ERR,"can't connect to target - %m"); 33335137Sphk close(net); 33435137Sphk Finish(6); 33535137Sphk } 33635137Sphk 33735137Sphk /* Demonize it */ 33835137Sphk daemon(0,0); 33935137Sphk 34035137Sphk /* Install signal handlers */ 34135137Sphk (void)signal(SIGHUP,Finish); 34235137Sphk (void)signal(SIGINT,Finish); 34335137Sphk (void)signal(SIGTERM,Finish); 34435137Sphk 34589583Sbillf if (tun > net) 34689583Sbillf lastfd = tun; 34789583Sbillf else 34889583Sbillf lastfd = net; 34989583Sbillf 35035137Sphk for (;;) { 35135137Sphk /* Set file descriptors for select() */ 35289583Sbillf FD_ZERO(&rfds); 35335137Sphk FD_SET(tun,&rfds); FD_SET(net,&rfds); 35435137Sphk 35589583Sbillf nfds = select(lastfd+1,&rfds,NULL,NULL,NULL); 35635137Sphk if(nfds < 0) { 35737669Scharnier syslog(LOG_ERR,"interrupted select"); 35835137Sphk close(net); 35935137Sphk Finish(7); 36035137Sphk } 36135137Sphk if(nfds == 0) { /* Impossible ? */ 36237669Scharnier syslog(LOG_ERR,"timeout in select"); 36335137Sphk close(net); 36435137Sphk Finish(8); 36535137Sphk } 36635137Sphk 36735137Sphk 36835137Sphk if(FD_ISSET(net,&rfds)) { 36935137Sphk /* Read from socket ... */ 37035137Sphk len = read(net, buf, sizeof(buf)); 37135137Sphk /* Check if this is "our" packet */ 37235137Sphk if((ip->ip_src).s_addr == (to->sin_addr).s_addr) { 37335137Sphk /* ... skip encapsulation headers ... */ 37435137Sphk ipoff = (ip->ip_hl << 2); 37535137Sphk /* ... and write to tun-device */ 37635137Sphk write(tun,buf+ipoff,len-ipoff); 37735137Sphk } 37835137Sphk } 37935137Sphk 38035137Sphk if(FD_ISSET(tun,&rfds)) { 38135137Sphk /* Read from tun ... */ 38235137Sphk len = read(tun, buf, sizeof(buf)); 38335137Sphk /* ... and send to network */ 38435137Sphk if(send(net, buf, len,0) <= 0) { 38537669Scharnier syslog(LOG_ERR,"can't send - %m"); 38635137Sphk } 38735137Sphk } 38835137Sphk } 38935137Sphk} 39035137Sphk 39135734Scharnierstatic void 392204966Suqsusage(void) 39335734Scharnier{ 39435734Scharnier fprintf(stderr, 395141611Sru"usage: nos-tun -t tunnel -s source -d destination -p protocol_number [source] target\n"); 39635734Scharnier exit(1); 39735734Scharnier} 39835734Scharnier 399