Hello! I found that if there is net-misc/openvpn, when I do /etc/init.d/net.tun0, It was done by openvpn. But there is a problem that tun interfaces settled by openvpn didn't work in app-emulation/qemu and app-emulation/virtualbox-ose. I think that we must have an option in /etc/conf.d/net, which util configure interface.
The current tuntap.sh Gentoo rc library script (at /lib/rc/net/tuntap.sh) supports iproute2 to handle creation of tap devices. Installation of sys-apps/iproute2 should resolve this issue without need for further changes.
(In reply to comment #1) thanks for tracking this down