Howdy how
BenBE asked me to give him some advice how to open and manipulate network devices from user space.
Although it’s not really a kernel hacking issue, as his way of asking proposed I’ll post the respective link after all, because I’ve promised.
Usually you use APIs for such a purpose.
In this case its the library called Libdnet and the project page can be found under the following URL:
http://libdnet.sourceforge.net/
I just have taken a look into Debian’s package viewer and somehow the relevant header (Â /usr/include/dnet/tun.h )
is missing ( packages broken/outdated? O.o)
Anyway, the header file would only tell us that much (Thx to benny for the tip with the highlighter! 😉 ):
/*
* tun.h
*
* Network tunnel device.
*
* Copyright (c) 2001 Dug Song
*
* $Id: tun.h,v 1.2 2005/01/25 21:29:12 dugsong Exp $
*/
#ifndef DNET_TUN_H
#define DNET_TUN_H
typedef struct tun tun_t;
__BEGIN_DECLS
tun_t *tun_open(struct addr *src, struct addr *dst, int mtu);
int tun_fileno(tun_t *tun);
const char *tun_name(tun_t *tun);
ssize_t tun_send(tun_t *tun, const void *buf, size_t size);
ssize_t tun_recv(tun_t *tun, void *buf, size_t size);
tun_t *tun_close(tun_t *tun);
__END_DECLS
#endif /* DNET_TUN_H */
An example can be found a little more deeper on the following site:
http://csfacwiki.cslabs.ewu.edu/wiki/securitylab/index.php/Libdnet
By using libudev for dynamic file checking and path allocation
you could also make it a little more dynamic and flexible.
(Using hardcoded strings in order to allocate files is usually a very bad idea)