Hi, I previously contacted tun driver maintainer about a bug I found and he suggested me to forward this to you. so, look like there is a bug in the kernel when the VLAN code is dealing with an interface like the tun interface.
see forwarded my original mail and Max reply. thanks! ---------- Forwarded message ---------- From: Max Krasnyansky <[EMAIL PROTECTED]> Date: Oct 29, 2007 8:29 PM Subject: Re: Bug with tun0 and VLAN To: Bruno Clermont <[EMAIL PROTECTED]> Hi Bruno, > Hi, > > I'm writing to you, because you seem to be the maintainer of the tun driver. > > I hit a bug lately. I was testing this scenario: > > [Server1][eth0]-------(Internet)----------[eth0][Server2] > > I want to be able to route traffic for many VLAN into a single tunnel > instead of invoking 1 openvpn process per VLAN. so, I tried to add VLAN > to tun interface. > > I create an OpenVPN tunnel between Server1 and 2, this part work. the > tun0 is going up. I use heavily openvpn and I'm sure of me on this part. > I made sure openvpn did not set any IP on the tunnel. > > So, I added the vlan to the tun interface on both server: > > ifconfig tun0 up > vconfig add tun0 1 > vconfig add tun1 2 > > on server1: > ifconfig tun0.1 10.0.0.1 <http://10.0.0.1> netmask 255.255.255.0 > <http://255.255.255.0> up > ifconfig tun0.1 10.0.1.1 <http://10.0.1.1> netmask 255.255.255.0 > <http://255.255.255.0> up > > on server2: > ifconfig tun0.1 10.0.0.2 <http://10.0.0.2> netmask 255.255.255.0 > <http://255.255.255.0> up > ifconfig tun0.1 10.0.1.2 <http://10.0.1.2> netmask 255.255.255.0 > <http://255.255.255.0> up > > Trying to ping the other end of the tun/vlan make the kernel panic on > the host that try to ping. > I tried on Ubuntu Feisty and Gutsy (2.6.22) and they both crash. > > I tried it severals times on different host and it seem that combining > VLAN and tun interface crash the kernel. > it's easy to reproduce. > > Is it a tun driver issue? VLAN code issue? some other part of the > kernel? I don't know. > > your my first attempt of communication for this issue... If it's not > supported, at least the kernel should not panic! Actually TUN is a point to point device, it does not have Ethernet MAC headers. In other words VLANs would never work over TUN. I agree though that it should not crash. So it's better to report this to netdev mailing list. Basically VLAN code should outright refuse to attach to TUN devices. Max - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
