Virtual network devices

Tun/tap

Allocate a tun/tap device

Note that tun/tap device can only be enabled by attaching an application to it.

sudo ip tuntap add dev tun0 mode {tun|tap}

Program interface

Create a new interface or to attach to a persistent interface.

1. Open /dev/net/tun file and obtain the file descriptor.

2. Issue an ioctl() system call and if it succeeds, the virtual interface is created and the file descriptor we had is now associated to it, and can be used to communicate.

Bridge

Allocate a bridge device

sudo ip link add name br0 type bridge

Attach a device to a bridge

Note that tun device cannot be bridged because it does not have MAC address.

sudo ip link set tap0 master br0

References

1. Tun/Tap interface tutorial