Hello,
I wanted to install OpenVPN on my firewall machine (an Ultra1 running
2.4.18), but unfortunately, I failed.
I managed to track the failing code, and tried to find equivalent
known-to-be-good code (found in the Linux Kernel documentation, in
networking/tuntap.txt).
The following code fails:
-----
int tun_alloc(char *dev)
{
struct ifreq ifr;
int fd, err;
if ((fd = open("/dev/net/tun", O_RDWR)) < 0)
{
perror("Unable to open /dev/net/tun");
return -1;
}
memset(&ifr, 0, sizeof(ifr));
/* Flags: IFF_TUN - TUN device (no Ethernet headers)
* IFF_TAP - TAP device
* IFF_NO_PI - Do not provide packet information
*/
ifr.ifr_flags = IFF_TUN;
if (*dev)
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
if ((err = ioctl(fd, TUNSETIFF, (void *) &ifr)) < 0)
{
close(fd);
perror("ioctl(fd, TUNSETIFF, ...) error");
return err;
}
strcpy(dev, ifr.ifr_name);
return fd;
}
-----
I tested this in a small program (just add a main() asking for an
argument, and call the tun_alloc() with the given argument). It fails on 2
ultrasparc machines (an U1 and an U2 running the same kernel version, the
U1 also has the IPVS patch applied), and works on a standard PC also
running the 2.4.18 kernel. Tun/Tap support is compiled in (if it wasn't,
the failure would have been at the open() call).
What I get is:
-----
Opening tun0
ioctl(fd, TUNSETIFF, ...) error: : Invalid argument
-----
I also get something in my syslog.log file:
Jan 30 15:15:39 herisson kernel: sys32_ioctl(tun:4329): Unknown cmd fd(3) cmd(800454ca) arg(effffc70)
What am I doing wrong?