[Vtun-devel] IOCTL problems on linux-2.4.14

[Helge J. <je...@sl...>]

I tried to install vtun on a stock linux-2.4.14 kernel, and have hit 
IOCTL problems. I have ploughed throug both vtun-devel and vtun-users 
but it does not seem (to me) that I am hitting the IOCTL problems 
described on vtun-devel....

I have downloaded vtun-2.5b1.tgz and compilation goes smootly, but i get:

   [root@apollon sbin]# strace -ff ./vtund -n -f /etc/vtund.client.conf 
aarhus_helge-home 194.239.238.2
   ...
   open("/dev/net/tun", O_RDWR)            = 5
   ioctl(5, 0x400454ca, 0xbffff450)        = -1 EINVAL (Invalid argument)
   close(5)                                = 0
   ...
   writev(2, [{"vtund[16936]: Can\'t allocate tun"..., 61}, {"\n", 1}], 
   2vtund[16936]: Can't allocate tun device. Invalid argument(22)
   ) = 62


I seem to be using the correct headers for compilation, since I have:

   #define TUNSETIFF     _IOW('T', 202, int)

in /usr/src/linux-2.4.14/include/linux/if_tun.h

and gcc ...[all the other options] -dM -E tun_dev.c | grep TUNSETIFF says:

   #define TUNSETIFF _IOW('T', 202, int)

I tried with the latest tun_dev.c from CVS (revision 1.2), but that gave 
the same result.

I can verify (using a debugger) that the offending call is the 
ioctl-call in tun_dev.c:88, which returns (as can also be seen from the 
strace) -1 EINVAL, with errno set to 22, meaning "Invalid argument".

Has anyone got any idea about how i should go about debugging this, 
short of inserting printk lines in linux-2.4.14/drivers/net/tun.c ?

-- 
Helge Jensen