sysdep-bsd-new.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 1.1.2.2 2000/11/20 08:15:53 maxk Exp $
  21  */
  22
  23 #include <unistd.h>
  24 #include <fcntl.h>
  25 #include <errno.h>
  26 #include <stdlib.h>
  27 #include <stdio.h>
  28 #include <string.h>
  29 #include <syslog.h>
  30 #include <sys/ioctl.h>
  31 #include <stdarg.h>
  32
  33 #include <sys/socket.h>
  34 #include <net/if.h>
  35 #include <net/if_tun.h>
  36
  37 #include "sysdep.h"
  38
  39 /*
  40  * Allocate TUN device, returns opened fd.
  41  * Stores dev name in the first arg(must be large enough).
  42  */
  43 int tun_open(char *dev)
  44 {
  45     char tunname[14];
  46     int i, fd;
  47
  48     if( *dev ) {
  49        sprintf(tunname, "/dev/%s", dev);
  50        return open(tunname, O_RDWR);
  51     }
  52
  53     for(i=0; i < 255; i++){
  54        sprintf(tunname, "/dev/tun%d", i);
  55        /* Open device */
  56        if( (fd=open(tunname, O_RDWR)) > 0 ){
  57           sprintf(dev, "tun%d", i);
  58           return fd;
  59        }
  60     }
  61     return -1;
  62 }
  63
  64 int tun_close(int fd, char *dev)
  65 {
  66     dev = NULL; /*unused*/
  67     return close(fd);
  68 }
  69
  70 /* Read/write frames from TUN device */
  71 int tun_write(int fd, char *buf, int len)
  72 {
  73     return write(fd, buf, len);
  74 }
  75
  76 int tun_read(int fd, char *buf, int len)
  77 {
  78     return read(fd, buf, len);
  79 }
  80
  81 /***********************************************************************/
  82 /* other support functions */
  83
  84 void config_tunnel(const char *dev, struct in_addr myaddr)
  85 {
  86   int sock;
  87   struct ifreq ifr;
  88   struct  in_aliasreq ifra_old, ifra_new;
  89   uint8_t *addr;
  90
  91   /* prepare socket and ifr */
  92   sock = socket (AF_INET, SOCK_DGRAM, 0);
  93   if (sock < 0)
  94     error (1, errno, "making socket");
  95   memset (&ifr, 0, sizeof(ifr));
  96   memset (&ifra_new, 0, sizeof(ifra_new));
  97   memcpy (ifr.ifr_name, dev, IFNAMSIZ);
  98   memcpy (ifra_new.ifra_name, dev, IFNAMSIZ);
  99
 100   /* set my address */
 101   ifra.ifra_addr.sa_family = AF_INET;
 102   addr = (uint8_t *)&((struct sockaddr_in *)&ifra_new.ifra_addr)->sin_addr;
 103   memcpy (addr, &myaddr, 4);
 104
 105   /* set dest address (== my addr) */
 106   ifra.ifra_dstaddr.sa_family = AF_INET;
 107   addr = (uint8_t *)&((struct sockaddr_in *)&ifra_new.ifra_dstaddr)->sin_addr;
 108   memcpy (addr, &myaddr, 4);
 109
 110   /* set netmask (== 255.255.255.255) */
 111   ifra.ifra_mask.sa_family = AF_INET;
 112   addr = (uint8_t *)&((struct sockaddr_in *)&ifra_new.ifra_mask)->sin_addr;
 113   memset (addr, 0xFF, 4);
 114
 115   /* set MTU */
 116   /* The magic constants are:
 117      1500  the normal ethernet MTU
 118      -20   the size of an IP header
 119      -8    the size of an ESP header
 120      -2    minimum padding length
 121      -12   the size of the HMAC
 122   ifr.ifr_mtu = 1500-20-8-2-12;
 123    Override: experimental found best value */
 124   ifr.ifr_mtu = 1412;
 125   if (ioctl (sock, SIOCSIFMTU, &ifr) != 0)
 126     error (1, errno, "setting interface MTU");
 127
 128   /* set interface flags */
 129   if (ioctl (sock, SIOCGIFFLAGS, &ifr) != 0)
 130     error (1, errno, "getting interface flags");
 131   ifr.ifr_flags |= (IFF_UP | IFF_RUNNING);
 132   if (ioctl (sock, SIOCSIFFLAGS, &ifr) != 0)
 133     error (1, errno, "setting interface flags");
 134
 135   close (sock);
 136 }
 137
 138 void error(int status, int errornum, const char *fmt, ...)
 139 {
 140         char   *buf2;
 141         va_list        ap;
 142
 143         va_start(ap, fmt);
 144         vasprintf(&buf2, fmt, ap);
 145         va_end(ap);
 146         fprintf(stderr, "%s", buf2);
 147         if (errornum)
 148                 fprintf(stderr, ": %s\n", strerror(errornum));
 149         free(buf2);
 150
 151         if (status)
 152                 exit(status);
 153 }
 154
 155 int getline(char **line, size_t *length, FILE *stream)
 156 {
 157         char *tmpline;
 158         size_t len;
 159
 160         tmpline = fgetln(stream, &len);
 161         if (feof(stream))
 162                 return -1;
 163         if (*line == NULL) {
 164                 *line = malloc(len + 1);
 165                 *length = len + 1;
 166         }
 167         if (*length < len + 1) {
 168                 *line = realloc(*line, len + 1);
 169                 *length = len + 1;
 170         }
 171         if (*line == NULL)
 172                 return -1;
 173         memcpy(*line, tmpline, len);
 174         (*line)[len] = '\0';
 175         return len;
 176 }