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Monday, 26 August 2019

libtuntap 0.4

The portable Tun/Tap devices configuration utility.
libtuntap is a library for configuring TUN or TAP devices in a portable manner.

Contents

  1. Description
  2. Install
  3. Notes
  4. Contributing
  5. License

Description

TUN and TAP are virtual networking devices which allow userland applications to receive packets sent to it. The userland applications can also send their own packets to the devices and they will be forwarded to the kernel.
This is useful for developping tunnels, private networks or virtualisation systems.

Supported Features

  • Creation of TUN and TAP devices;
  • Autodetection of available TUN or TAP devices;
  • Setting and getting the MAC address of the device;
  • Setting and getting the MTU of the device;
  • Setting the status of the device (up/down);
  • Setting the IPv4 address and netmask of the device;
  • Setting the persistence mode of the device;
  • Setting the name of the device (Linux only);
  • Setting the description of the device (OpenBSD and FreeBSD only);
  • Wrapper libraries for other languages.

Supported Systems

  • OpenBSD;
  • Linux;
  • NetBSD;
  • Darwin (up to High Sierra).

Current Porting Efforts

  • Windows;
  • FreeBSD.

In the future

  • AIX;
  • Solaris.

Install

Requires

  • cmake;
  • C and C++ compilers.

Build

This project is built with cmake:
$ mkdir build; cd build
$ cmake ../
$ make
# make install
It is possible to tweak the destination folder for the install rule with the environment variable DESTDIR. The default behaviour is to install under the /usr/lib folder for Linux and /usr/local/lib for everyone else.
Example make invocation:
$ DESTDIR=/tmp make install
The following options can be tweaked:
  • ENABLE_CXX: Enable building of the C++ wrapper library libtuntap++;
  • ENABLE_PYTHON: Enable building of the Python wrapper library pytuntap;
  • BUILD_TESTING: Enable building of the regress tests;
  • BUILD_SHARED_LIBS: Build shared libraries instead of static ones.

Other languages bindings

We currently provide wrappers for two other languages: C++ and Python, respectively named libtuntap++ and pytuntap. More instructions about them is provided in the bindings folder.
The C++ library is built by default and can be disabled with the flag ENABLE_CXX.
The Python library is disabled by default and requires both ENABLE_CXX and ENABLE_PYTHON to work. You will also need Python 3.6 and Boost libraries.
Example cmake invocation:
$ mkdir build; cd build
$ cmake -D ENABLE_CXX=ON -D ENABLE_PYTHON=ON ../

Tests

A series of regress tests can be built with the BUILD_TESTING option. They are enabled by default. A list and a description for each of them can be found in the regress folder.
Example cmake invocation:
$ mkdir build; cd build
$ cmake -D BUILD_TESTING=ON ../
# make test

Static or shared

Up to version 0.3 the libtuntap CMakeFiles.txt exported two libraries: one shared, one static. To simplify the building of the wrapper libraries it was decided to only build one. The default is to build a static library but this behaviour can be changed with the option BUILD_SHARED_LIBS.
Example cmake invocation:
$ mkdir build; cd build
$ cmake -D BUILD_SHARED_LIBS=ON ../
$ make

Local configurations

The main CMakeFiles.txt includes an optional CMakeFiles.txt.local which can be used to store persistent options across builds.
Example:
$ cat CMakeLists.txt.local
set(BUILD_SHARED_LIBS ON)
set(BUILD_TESTING OFF)
set(ENABLE_CXX OFF)

Notes

Notes for Mac OS X users

You need to install the tuntaposx project for this library to be useful, which is a third-party kext.

Notes for Windows users

You need to install the tap-windows driver provided by the OpenVPN project.

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