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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 1.6.2.3 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 <sys/types.h>
#include <sys/uio.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if_tun.h>
#include "vtun.h"
#include "lib.h"
/*
* Allocate TUN device, returns opened fd.
* Stores dev name in the first arg(must be large enough).
*/
int tun_open(char *dev)
{
char tunname[14];
int i, fd = -1;
if( *dev ){
sprintf(tunname, "/dev/%s", dev);
fd = open(tunname, O_RDWR);
} else {
for(i=0; i < 255; i++){
sprintf(tunname, "/dev/tun%d", i);
/* Open device */
if( (fd=open(tunname, O_RDWR)) > 0 ){
sprintf(dev, "tun%d", i);
break;
}
}
}
return fd;
}
int tun_close(int fd, char *dev)
{
return close(fd);
}
/* Read/write frames from TUN device */
int tun_write(int fd, char *buf, int len)
{
u_int32_t type = htonl(AF_INET);
struct iovec iv[2];
iv[0].iov_base = &type;
iv[0].iov_len = sizeof(type);
iv[1].iov_base = buf;
iv[1].iov_len = len;
return writev(fd, iv, 2);
}
int tun_read(int fd, char *buf, int len)
{
struct iovec iv[2];
u_int32_t type;
register int rlen;
iv[0].iov_base = &type;
iv[0].iov_len = sizeof(type);
iv[1].iov_base = buf;
iv[1].iov_len = len;
if( (rlen = readv(fd, iv, 2)) > 0 )
return rlen - sizeof(type);
else
return rlen;
}
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