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/*
VTun - Virtual Tunnel over TCP/IP network.
Copyright (C) 1998-2016 Maxim Krasnyansky <max_mk@yahoo.com>
VTun has been derived from VPPP package by Maxim Krasnyansky.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
*/
/*
* $Id: tun_dev.c,v 1.4.2.2 2016/10/01 21:46:01 mtbishop Exp $
*/
#include "config.h"
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <errno.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <linux/if.h>
#include "vtun.h"
#include "lib.h"
/*
* Allocate TUN device, returns opened fd.
* Stores dev name in the first arg(must be large enough).
*/
static int tun_open_common0(char *dev, int istun)
{
char tunname[14];
int i, fd, err;
if( *dev ) {
sprintf(tunname, "/dev/%s", dev);
return open(tunname, O_RDWR);
}
sprintf(tunname, "/dev/%s", istun ? "tun" : "tap");
err = 0;
for(i=0; i < 255; i++){
sprintf(tunname + 8, "%d", i);
/* Open device */
if( (fd=open(tunname, O_RDWR)) > 0 ) {
strcpy(dev, tunname + 5);
return fd;
}
else if (errno != ENOENT)
err = errno;
else if (i) /* don't try all 256 devices */
break;
}
if (err)
errno = err;
return -1;
}
#ifdef HAVE_LINUX_IF_TUN_H /* New driver support */
#include <linux/if_tun.h>
#ifndef OTUNSETNOCSUM
/* pre 2.4.6 compatibility */
#define OTUNSETNOCSUM (('T'<< 8) | 200)
#define OTUNSETDEBUG (('T'<< 8) | 201)
#define OTUNSETIFF (('T'<< 8) | 202)
#define OTUNSETPERSIST (('T'<< 8) | 203)
#define OTUNSETOWNER (('T'<< 8) | 204)
#endif
static int tun_open_common(char *dev, int istun)
{
struct ifreq ifr;
int fd;
if ((fd = open("/dev/net/tun", O_RDWR)) < 0)
return tun_open_common0(dev, istun);
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = (istun ? IFF_TUN : IFF_TAP) | IFF_NO_PI;
if (*dev)
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
if (ioctl(fd, TUNSETIFF, (void *) &ifr) < 0) {
if (errno == EBADFD) {
/* Try old ioctl */
if (ioctl(fd, OTUNSETIFF, (void *) &ifr) < 0)
goto failed;
} else
goto failed;
}
strcpy(dev, ifr.ifr_name);
return fd;
failed:
close(fd);
return -1;
}
#else
# define tun_open_common(dev, type) tun_open_common0(dev, type)
#endif /* New driver support */
int tun_open(char *dev) { return tun_open_common(dev, 1); }
int tap_open(char *dev) { return tun_open_common(dev, 0); }
int tun_close(int fd, char *dev) { return close(fd); }
int tap_close(int fd, char *dev) { return close(fd); }
/* Read/write frames from TUN device */
int tun_write(int fd, char *buf, int len) { return write(fd, buf, len); }
int tap_write(int fd, char *buf, int len) { return write(fd, buf, len); }
int tun_read(int fd, char *buf, int len) { return read(fd, buf, len); }
int tap_read(int fd, char *buf, int len) { return read(fd, buf, len); }
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