2009-04-20 16:08:52 Cannot allocate TUN/TAP dev dynamically
blue hash (UNITED STATES)
Message: 72907
Hi,
I am trying out openvpm on the bf537. 2008R1.5-RC3
I followed the following guide, which is very good
http://www.vpx.nu/dokuwiki/doku.php?id=vpn_solutions&s=tar
In the above guide node /dev/net/tun is added in the device_table.txt file
/dev/net d 755 0 0 - - - - -
/dev/net/tun c 640 0 0 10 200 0 0 -
However on boot, these do not get created and I get the following error.
Mon Apr 20 15:36:10 2009 OPTIONS IMPORT: timers and/or timeouts modified
Mon Apr 20 15:36:10 2009 OPTIONS IMPORT: --ifconfig/up options modified
Mon Apr 20 15:36:10 2009 OPTIONS IMPORT: route options modified
Mon Apr 20 15:36:10 2009 OPTIONS IMPORT: --ip-win32 and/or --dhcp-option options modified
Mon Apr 20 15:36:10 2009 Note: Cannot ioctl TUNSETIFF tun: Invalid argument (errno=22)
Mon Apr 20 15:36:10 2009 Note: Attempting fallback to kernel 2.2 TUN/TAP interface
Mon Apr 20 15:36:10 2009 Cannot allocate TUN/TAP dev dynamically
Mon Apr 20 15:36:10 2009 Exiting
Do I have to add anything to the board resource file?
I do see the following on boot:
SMSC LAN83C185: Registered new driver
tun: Universal TUN/TAP device driver, 1.6
tun: (C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>
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2009-04-20 18:36:10 Re: Cannot allocate TUN/TAP dev dynamically
Mike Frysinger (UNITED STATES)
Message: 72911
there is nothing that needs to be added to your board resources. you simply need to make sure you've enabled the TUN/TAP driver under the networking driver options in your kernel configuration.
same goes for /dev -- do not try to create the device nodes yourself at all
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2009-04-21 12:19:30 Re: Cannot allocate TUN/TAP dev dynamically
blue hash (UNITED STATES)
Message: 73007
HI Mike, thanks for clearing up my text mess. I had the driver enabled in config, but for some reason couldnt see it in /dev/net. I'm aware that post 2008R1 releases create nodes dynamically by scanning /sys. Just for the heck, when I created /dev/net tun through mknod /dev/net/tun 10 200, the error went away.
I know I shouldnt do this but it worked. Could it be a bug? Thanks.
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2009-04-22 12:10:14 Re: Cannot allocate TUN/TAP dev dynamically
Mike Frysinger (UNITED STATES)
Message: 73068
if you delete the node and run `mdev -s`, does it show up again ?
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2009-10-27 05:17:22 Re: Cannot allocate TUN/TAP dev dynamically
Øyvind Kaurstad (NORWAY)
Message: 81774
This thread is a few months old, but I'm seeing the same issue, and I wonder why.
For some reason, the tun device node is default created at /dev/tun, not /dev/net/tun which OpenVPN seems to expect by default.
I did some experimenting, and by either explicitly telling OpenVPN that it should use /dev/tun (by using the --dev-node option) or manually creating /dev/net and setting a symlink to /dev/tun it works. It is also possible to create /dev/net and then use mknod to set up the tun device, but that's not the correct way I presume.
I have been trying to figure out why tun is at /dev/tun and not /dev/net/tun, but my lack of experience is shining through. Could someone please enlighten me here?
I'm using the 2009R1, btw.
Regards
-Øyvind
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2009-10-27 05:23:48 Re: Cannot allocate TUN/TAP dev dynamically
Mike Frysinger (UNITED STATES)
Message: 81775
mdev only creates devices in /dev/ without subdirs unless there is a rule for it. so there probably needs a line added to mdev.conf that says tun should be placed under net/.
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2009-10-28 09:56:03 Re: Cannot allocate TUN/TAP dev dynamically
Øyvind Kaurstad (NORWAY)
Message: 81813
Thanks for answering.
I added the following line to mdev.conf:
tun[0-9]* 0:0 0660 =net/
..and that moves the tun device to /dev/net, which makes a default OpenVPN happy.
-Øyvind