nos-tun.c revision 121540
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: head/sbin/nos-tun/nos-tun.c 121540 2003-10-26 04:37:57Z peter $"; 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 9235137Sphkint Set_address(char *addr, struct sockaddr_in *sin) 9335137Sphk{ 9435137Sphk struct hostent *hp; 9535137Sphk 9635137Sphk bzero((char *)sin, sizeof(struct sockaddr)); 9735137Sphk sin->sin_family = AF_INET; 98121540Speter if((sin->sin_addr.s_addr = inet_addr(addr)) == (in_addr_t)-1) { 9935137Sphk hp = gethostbyname(addr); 10035137Sphk if (!hp) { 10137669Scharnier syslog(LOG_ERR,"unknown host %s", addr); 10235137Sphk return 1; 10335137Sphk } 10435137Sphk sin->sin_family = hp->h_addrtype; 10535137Sphk bcopy(hp->h_addr, (caddr_t)&sin->sin_addr, hp->h_length); 10635137Sphk } 10735137Sphk return 0; 10835137Sphk} 10935137Sphk 11035137Sphkint tun_open(char *devname, struct sockaddr *ouraddr, char *theiraddr) 11135137Sphk{ 11235137Sphk int s; 11335137Sphk struct sockaddr_in *sin; 11435137Sphk 11535137Sphk /* Open tun device */ 11635137Sphk tun = open (devname, O_RDWR); 11735137Sphk if (tun < 0) { 11837669Scharnier syslog(LOG_ERR,"can't open %s - %m",devname); 11935137Sphk return(1); 12035137Sphk } 12135137Sphk 12235137Sphk /* 12335137Sphk * At first, name the interface. 12435137Sphk */ 12535137Sphk bzero((char *)&ifra, sizeof(ifra)); 12635137Sphk bzero((char *)&ifrq, sizeof(ifrq)); 12735137Sphk 12835137Sphk strncpy(ifrq.ifr_name, devname+5, IFNAMSIZ); 12935137Sphk strncpy(ifra.ifra_name, devname+5, IFNAMSIZ); 13035137Sphk 13135137Sphk s = socket(AF_INET, SOCK_DGRAM, 0); 13235137Sphk if (s < 0) { 13338023Sbde syslog(LOG_ERR,"can't open socket - %m"); 13435137Sphk goto tunc_return; 13535137Sphk } 13635137Sphk 13735137Sphk /* 13880203Skris * Delete (previous) addresses for interface 13935137Sphk * 14035137Sphk * !!!! 14135137Sphk * On FreeBSD this ioctl returns error 14235137Sphk * when tunN have no addresses, so - log and ignore it. 14335137Sphk * 14435137Sphk */ 14535137Sphk if (ioctl(s, SIOCDIFADDR, &ifra) < 0) { 14635137Sphk syslog(LOG_ERR,"SIOCDIFADDR - %m"); 14735137Sphk } 14835137Sphk 14935137Sphk /* 15035137Sphk * Set interface address 15135137Sphk */ 15235137Sphk sin = (struct sockaddr_in *)&(ifra.ifra_addr); 15335137Sphk bcopy(ouraddr, sin, sizeof(struct sockaddr_in)); 15435137Sphk sin->sin_len = sizeof(*sin); 15535137Sphk 15635137Sphk /* 15735137Sphk * Set destination address 15835137Sphk */ 15935137Sphk sin = (struct sockaddr_in *)&(ifra.ifra_broadaddr); 16035137Sphk if(Set_address(theiraddr,sin)) { 16137669Scharnier syslog(LOG_ERR,"bad destination address: %s",theiraddr); 16235137Sphk goto stunc_return; 16335137Sphk } 16435137Sphk sin->sin_len = sizeof(*sin); 16535137Sphk 16635137Sphk if (ioctl(s, SIOCAIFADDR, &ifra) < 0) { 16737669Scharnier syslog(LOG_ERR,"can't set interface address - %m"); 16835137Sphk goto stunc_return; 16935137Sphk } 17035137Sphk 17135137Sphk /* 17235137Sphk * Now, bring up the interface. 17335137Sphk */ 17435137Sphk if (ioctl(s, SIOCGIFFLAGS, &ifrq) < 0) { 17537669Scharnier syslog(LOG_ERR,"can't get interface flags - %m"); 17635137Sphk goto stunc_return; 17735137Sphk } 17835137Sphk 17935137Sphk ifrq.ifr_flags |= IFF_UP; 18035137Sphk if (!(ioctl(s, SIOCSIFFLAGS, &ifrq) < 0)) { 18135137Sphk close(s); 18235137Sphk return(0); 18335137Sphk } 18437669Scharnier syslog(LOG_ERR,"can't set interface UP - %m"); 18535137Sphkstunc_return: 18635137Sphk close(s); 18735137Sphktunc_return: 18835137Sphk close(tun); 18935137Sphk return(1); 19035137Sphk} 19135137Sphk 19235137Sphkvoid Finish(int signum) 19335137Sphk{ 19435137Sphk int s; 19535137Sphk 19637669Scharnier syslog(LOG_INFO,"exiting"); 19735137Sphk 19835137Sphk close(net); 19935137Sphk 20035137Sphk s = socket(AF_INET, SOCK_DGRAM, 0); 20135137Sphk if (s < 0) { 20237669Scharnier syslog(LOG_ERR,"can't open socket - %m"); 20335137Sphk goto closing_tun; 20435137Sphk } 20535137Sphk 20635137Sphk /* 20735137Sphk * Shut down interface. 20835137Sphk */ 20935137Sphk if (ioctl(s, SIOCGIFFLAGS, &ifrq) < 0) { 21037669Scharnier syslog(LOG_ERR,"can't get interface flags - %m"); 21135137Sphk goto closing_fds; 21235137Sphk } 21335137Sphk 21435137Sphk ifrq.ifr_flags &= ~(IFF_UP|IFF_RUNNING); 21535137Sphk if (ioctl(s, SIOCSIFFLAGS, &ifrq) < 0) { 21637669Scharnier syslog(LOG_ERR,"can't set interface DOWN - %m"); 21735137Sphk goto closing_fds; 21835137Sphk } 21935137Sphk 22035137Sphk /* 22180203Skris * Delete addresses for interface 22235137Sphk */ 22335137Sphk bzero(&ifra.ifra_addr, sizeof(ifra.ifra_addr)); 22435137Sphk bzero(&ifra.ifra_broadaddr, sizeof(ifra.ifra_addr)); 22535137Sphk bzero(&ifra.ifra_mask, sizeof(ifra.ifra_addr)); 22635137Sphk if (ioctl(s, SIOCDIFADDR, &ifra) < 0) { 22737669Scharnier syslog(LOG_ERR,"can't delete interface's addresses - %m"); 22835137Sphk } 22935137Sphkclosing_fds: 23035137Sphk close(s); 23135137Sphkclosing_tun: 23235137Sphk close(tun); 23335137Sphk closelog(); 23435137Sphk exit(signum); 23535137Sphk} 23635137Sphk 23735137Sphkint main (int argc, char **argv) 23835137Sphk{ 23935137Sphk int c, len, ipoff; 24035137Sphk 24135137Sphk char *devname = NULL; 24235137Sphk char *point_to = NULL; 24335137Sphk char *to_point = NULL; 24435137Sphk char *target; 24574948Sphk char *source = NULL; 24645114Sphk char *protocol = NULL; 24745114Sphk int protnum; 24835137Sphk 24935137Sphk struct sockaddr t_laddr; /* Source address of tunnel */ 25035137Sphk struct sockaddr whereto; /* Destination of tunnel */ 25174948Sphk struct sockaddr wherefrom; /* Source of tunnel */ 25235137Sphk struct sockaddr_in *to; 25335137Sphk 25435137Sphk char buf[0x2000]; /* Packets buffer */ 25535137Sphk struct ip *ip = (struct ip *)buf; 25635137Sphk 25789583Sbillf fd_set rfds; /* File descriptors for select() */ 25835137Sphk int nfds; /* Return from select() */ 25989583Sbillf int lastfd; /* highest fd we care about */ 26035137Sphk 26135137Sphk 26245114Sphk while ((c = getopt(argc, argv, "d:s:t:p:")) != -1) { 26335137Sphk switch (c) { 26435137Sphk case 'd': 26535137Sphk to_point = optarg; 26635137Sphk break; 26735137Sphk case 's': 26835137Sphk point_to = optarg; 26935137Sphk break; 27035137Sphk case 't': 27135137Sphk devname = optarg; 27235137Sphk break; 27345114Sphk case 'p': 27445114Sphk protocol = optarg; 27545114Sphk break; 27635137Sphk } 27735137Sphk } 27835137Sphk argc -= optind; 27935137Sphk argv += optind; 28035137Sphk 28174948Sphk if ((argc != 1 && argc != 2) || (devname == NULL) || 28235137Sphk (point_to == NULL) || (to_point == NULL)) { 28335734Scharnier usage(); 28435137Sphk } 28535137Sphk 28645114Sphk if(protocol == NULL) 28745114Sphk protnum = 94; 28845114Sphk else 28945114Sphk protnum = atoi(protocol); 29045114Sphk 29174948Sphk if (argc == 1) { 29274948Sphk target = *argv; 29374948Sphk } else { 29474948Sphk source = *argv++; target = *argv; 29574948Sphk } 29635137Sphk 29735137Sphk /* Establish logging through 'syslog' */ 29861438Sasmodai openlog("nos-tun", LOG_PID, LOG_DAEMON); 29935137Sphk 30035137Sphk if(Set_address(point_to, (struct sockaddr_in *)&t_laddr)) { 30135137Sphk closelog(); 30235137Sphk exit(2); 30335137Sphk } 30435137Sphk 30535137Sphk if(tun_open(devname, &t_laddr, to_point)) { 30635137Sphk closelog(); 30735137Sphk exit(3); 30835137Sphk } 30935137Sphk 31035137Sphk to = (struct sockaddr_in *)&whereto; 31135137Sphk if(Set_address(target, to)) 31235137Sphk Finish(4); 31335137Sphk 31445114Sphk if ((net = socket(AF_INET, SOCK_RAW, protnum)) < 0) { 31537669Scharnier syslog(LOG_ERR,"can't open socket - %m"); 31635137Sphk Finish(5); 31735137Sphk } 31835137Sphk 31974948Sphk if (source) { 32074948Sphk if (Set_address(source, (struct sockaddr_in *)&wherefrom)) 32174948Sphk Finish(9); 32274948Sphk if (bind(net, &wherefrom, sizeof(wherefrom)) < 0) { 32374948Sphk syslog(LOG_ERR, "can't bind source address - %m"); 32474948Sphk Finish(10); 32574948Sphk } 32674948Sphk } 32774948Sphk 32835137Sphk if (connect(net,&whereto,sizeof(struct sockaddr_in)) < 0 ) { 32937669Scharnier syslog(LOG_ERR,"can't connect to target - %m"); 33035137Sphk close(net); 33135137Sphk Finish(6); 33235137Sphk } 33335137Sphk 33435137Sphk /* Demonize it */ 33535137Sphk daemon(0,0); 33635137Sphk 33735137Sphk /* Install signal handlers */ 33835137Sphk (void)signal(SIGHUP,Finish); 33935137Sphk (void)signal(SIGINT,Finish); 34035137Sphk (void)signal(SIGTERM,Finish); 34135137Sphk 34289583Sbillf if (tun > net) 34389583Sbillf lastfd = tun; 34489583Sbillf else 34589583Sbillf lastfd = net; 34689583Sbillf 34735137Sphk for (;;) { 34835137Sphk /* Set file descriptors for select() */ 34989583Sbillf FD_ZERO(&rfds); 35035137Sphk FD_SET(tun,&rfds); FD_SET(net,&rfds); 35135137Sphk 35289583Sbillf nfds = select(lastfd+1,&rfds,NULL,NULL,NULL); 35335137Sphk if(nfds < 0) { 35437669Scharnier syslog(LOG_ERR,"interrupted select"); 35535137Sphk close(net); 35635137Sphk Finish(7); 35735137Sphk } 35835137Sphk if(nfds == 0) { /* Impossible ? */ 35937669Scharnier syslog(LOG_ERR,"timeout in select"); 36035137Sphk close(net); 36135137Sphk Finish(8); 36235137Sphk } 36335137Sphk 36435137Sphk 36535137Sphk if(FD_ISSET(net,&rfds)) { 36635137Sphk /* Read from socket ... */ 36735137Sphk len = read(net, buf, sizeof(buf)); 36835137Sphk /* Check if this is "our" packet */ 36935137Sphk if((ip->ip_src).s_addr == (to->sin_addr).s_addr) { 37035137Sphk /* ... skip encapsulation headers ... */ 37135137Sphk ipoff = (ip->ip_hl << 2); 37235137Sphk /* ... and write to tun-device */ 37335137Sphk write(tun,buf+ipoff,len-ipoff); 37435137Sphk } 37535137Sphk } 37635137Sphk 37735137Sphk if(FD_ISSET(tun,&rfds)) { 37835137Sphk /* Read from tun ... */ 37935137Sphk len = read(tun, buf, sizeof(buf)); 38035137Sphk /* ... and send to network */ 38135137Sphk if(send(net, buf, len,0) <= 0) { 38237669Scharnier syslog(LOG_ERR,"can't send - %m"); 38335137Sphk } 38435137Sphk } 38535137Sphk } 38635137Sphk} 38735137Sphk 38835734Scharnierstatic void 38935734Scharnierusage() 39035734Scharnier{ 39135734Scharnier fprintf(stderr, 39274948Sphk"usage: nos-tun -t <tun_name> -s <source_addr> -d <dest_addr> -p <protocol_number> [<source_addr>] <target_addr>\n"); 39335734Scharnier exit(1); 39435734Scharnier} 39535734Scharnier 396