tun_dev-svr4.c

   1 /*
   2     VTun - Virtual Tunnel over TCP/IP network.
   3
   4     Copyright (C) 1998-2000  Maxim Krasnyansky <max_mk@yahoo.com>
   5
   6     VTun has been derived from VPPP package by Maxim Krasnyansky.
   7
   8     This program is free software; you can redistribute it and/or modify
   9     it under the terms of the GNU General Public License as published by
  10     the Free Software Foundation; either version 2 of the License, or
  11     (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17  */
  18
  19 /*
  20  * $Id: tun_dev.c,v 1.2.2.2 2000/11/20 08:15:53 maxk Exp $
  21  */
  22
  23 #include <unistd.h>
  24 #include <fcntl.h>
  25 #include <stdlib.h>
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <ctype.h>
  29 #include <stdarg.h>
  30 #include <sys/time.h>
  31 #include <sys/wait.h>
  32 #include <syslog.h>
  33 #include <sys/types.h>
  34 #include <sys/socket.h>
  35 #include <sys/sockio.h>
  36 #include <sys/ioctl.h>
  37 #include <errno.h>
  38 #include <signal.h>
  39 #include <stropts.h>
  40 #include <net/if.h>
  41 #include <net/if_tun.h>
  42 #include <netinet/in.h>
  43 #include <netinet/in_systm.h>
  44 #include <netinet/ip.h>
  45 #include <netinet/tcp.h>
  46
  47 static int ip_fd = -1, muxid;
  48
  49 /*
  50  * Allocate TUN device, returns opened fd.
  51  * Stores dev name in the first arg(must be large enough).
  52  */
  53 int tun_open(char *dev)
  54 {
  55     int tun_fd, if_fd, ppa = -1;
  56     struct ifreq ifr;
  57     char *ptr;
  58
  59     if( *dev ){
  60        ptr = dev;
  61        while( *ptr && !isdigit((int)*ptr) ) ptr++;
  62        ppa = atoi(ptr);
  63     }
  64
  65     if( (ip_fd = open("/dev/udp", O_RDWR, 0)) < 0){
  66        syslog(LOG_ERR, "Can't open /dev/ip");
  67        return -1;
  68     }
  69
  70     if( (tun_fd = open("/dev/tun", O_RDWR, 0)) < 0){
  71        syslog(LOG_ERR, "Can't open /dev/tun");
  72        return -1;
  73     }
  74
  75     /* Assign a new PPA and get its unit number. */
  76     if( (ppa = ioctl(tun_fd, TUNNEWPPA, ppa)) < 0){
  77        syslog(LOG_ERR, "Can't assign new interface");
  78        return -1;
  79     }
  80
  81     if( (if_fd = open("/dev/tun", O_RDWR, 0)) < 0){
  82        syslog(LOG_ERR, "Can't open /dev/tun (2)");
  83        return -1;
  84     }
  85     if(ioctl(if_fd, I_PUSH, "ip") < 0){
  86        syslog(LOG_ERR, "Can't push IP module");
  87        return -1;
  88     }
  89
  90     /* Assign ppa according to the unit number returned by tun device */
  91     if(ioctl(if_fd, IF_UNITSEL, (char *)&ppa) < 0){
  92        syslog(LOG_ERR, "Can't set PPA %d", ppa);
  93        return -1;
  94     }
  95     if( (muxid = ioctl(ip_fd, I_PLINK, if_fd)) < 0){
  96        syslog(LOG_ERR, "Can't link TUN device to IP");
  97        return -1;
  98     }
  99     close(if_fd);
 100
 101     sprintf(dev, "tun%d", ppa);
 102
 103     memset(&ifr, 0, sizeof(ifr));
 104     strcpy(ifr.ifr_name, dev);
 105     ifr.ifr_ip_muxid = muxid;
 106
 107     if( ioctl(ip_fd, SIOCSIFMUXID, &ifr) < 0 ){
 108        ioctl(ip_fd, I_PUNLINK, muxid);
 109        syslog(LOG_ERR, "Can't set multiplexor id");
 110        return -1;
 111     }
 112
 113     return tun_fd;
 114 }
 115
 116 /*
 117  * Close TUN device.
 118  */
 119 int tun_close(int fd, char *dev)
 120 {
 121     struct ifreq ifr;
 122
 123     memset(&ifr, 0, sizeof(ifr));
 124     strcpy(ifr.ifr_name, dev);
 125     if( ioctl(ip_fd, SIOCGIFFLAGS, &ifr) < 0 ){
 126        syslog(LOG_ERR, "Can't get iface flags");
 127        return 0;
 128     }
 129
 130 #if 0
 131     if( ioctl(ip_fd, SIOCGIFMUXID, &ifr) < 0 ){
 132        syslog(LOG_ERR, "Can't get multiplexor id");
 133        return 0;
 134     }
 135     muxid = ifr.ifr_ip_muxid;
 136 #endif
 137
 138     if( ioctl(ip_fd, I_PUNLINK, muxid) < 0 ){
 139        syslog(LOG_ERR, "Can't unlink interface");
 140        return 0;
 141     }
 142
 143     close(ip_fd); close(fd);
 144     return 0;
 145 }
 146
 147 int tun_write(int fd, char *buf, int len)
 148 {
 149     struct strbuf sbuf;
 150     sbuf.len = len;
 151     sbuf.buf = buf;
 152     return putmsg(fd, NULL, &sbuf, 0) >=0 ? sbuf.len : -1;
 153 }
 154
 155 int tun_read(int fd, char *buf, int len)
 156 {
 157     struct strbuf sbuf;
 158     int f = 0;
 159
 160     sbuf.maxlen = len;
 161     sbuf.buf = buf;
 162     return getmsg(fd, NULL, &sbuf, &f) >=0 ? sbuf.len : -1;
 163 }