Category Archives: Tech

Accessing/manipulating networkdevices in C

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 ( /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is missing ( packages broken/outdated?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)

Gentoo: Emerging with RAMFS

Hi

bash_vi asked me to write a short resume about how to emerge programs by using the ramfs for speedup.
Here's how to do so:

mount -t ramfs -o size=2g ramfs /var/tmp/portage/

  • The "-t ramfs" is obviously self explainatory.
  • The "-o size" tells the ramfs driver how much space of the RAM should be reserved for this specific mount point.
  • "/var/tmp/portage/" is the place where portage usually unpacks the source boundles and begins to compile them.

You can also put it into your /etc/fstab in order to keep it for each reboot with
echo -e "ramfs\t/var/tmp/portage/\tramfs\tsize=2g\t0\t0" >> /etc/fstab

Now you can compile your stuff within RAMFS

Links:

  • http://de.gentoo-wiki.com/wiki/Emerge_beschleunigen
  • http://www.thegeekstuff.com/2008/11/overview-of-ramfs-and-tmpfs-on-linux/

notion ink adam - tegra devices

I'm really pissed.
It's again the same shit as with my HTC dream (or should I say nightmare?)
Ages outdated kernel, branches with drivers which are that badly written that they can never be merged into Torvalds master again.
Dudes! Can't you have a look over to Texas Instruments?!
The OMAP is well documented, there are free drivers available and there is always support in main.
WTF? What use is a kernel where no peripherial drivers are available within the official, recent kernel?!

Gentoo, KDE4 and OpenMoko and examina

Howdy

Long time has it been, now a tech-update

KDE4 and Gentoo
It's the small things in life which are important, like for example, finally figuring out, that just replacing "%d : %n" with "%d : %w" in my Konsole-profile finally also makes Konsole show me the recent package, emerge is compiling in the title-bar (like xterm always does)

OpenMoko
Tomorrow my 16GB µSD card should arrive, on which I'll install Kubuntu-Mobile, in order to test Plasma-Active on my GTA04

Examina
I'm really working this time on the stuff.
It's ETHZ matter of a year strechted onto two, so this time, it's doable... Hopefully...
It's looks well so far, anyway... 😉