dirkakrid / tun2udp

A pair of TUN/TAP drivers that wrap frames in UDP packets or SLIP/FIFO frames.

TUN2UDP

Implements a TUN or TAP device that simply forwards all packets from the device to a specified host over UDP, and the contents of any received UDP packets back to the TUN/TAP device.

Using tun2udp you can create simple network bridges or forward packets to another program for processing.

  make tun2udp   # Compile
  ./tun2udp -?   # Usage instructions

TUN2FIFO

Implements a TUN or TAP driver by reading and writing SLIP-encoded packets from a pair of files or pipes. TUN/TAP options are the same as for TUN2UDP.

  make tun2fifo  # Compile
  ./tun2fifo -?  # Usage instructions

The current implementation of TUN2FIFO uses a 2kB buffer and will have undefined behavior for packets larger than the buffer size (those packets will be garbled).

To increase or decrease the buffer size for both tun2udp and tun2fifo, edit bufsize.h.

Example

This example assumes we have 2 hosts with IPv6 addresses 2001:1234::1 and 2001:9876::5. If you want to join 2 IPv4 hosts, replace with the hosts' IPv4 addresses and leave out the square brackets.

To create a simple tunnel:

  sudo ./tun2udp -local-address '[2001:1234::1]:55511' \
    -remote-address '[2001:9876::5]:55511' -tun -no-pi \
    -tun-dev tun2udp1 &
  sudo ip link set tun2udp1 up
  sudo ip addr add 10.9.8.1/24 dev tun2udp1
  ping 10.9.8.2

And on the other machine:

  sudo ./tun2udp -local-address '[2001:9876::5]:55511' \
    -remote-address '[2001:1234::1]:55511' -tun -no-pi \
    -tun-dev tun2udp1 &
  sudo ip link set tun2udp1 up
  sudo ip addr add 10.9.8.2/24 dev tun2udp1
  ping 10.9.8.1

In this case you could use either -tun or -tap so long as it's the same on both ends.