strongSwan Developer Documentation » History » Version 42

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Tobias Brunner, 07.07.2014 17:17

strongSwan Developer Documentation


Before starting development, please read our contribution requirements.

Getting the Source Code

The easiest way to get the source code is checking it out from our Git repository:

git clone git://
The repository is also mirrored to GitHub.

Browsing the Source Code

The Git repository can be browsed online using either Gitweb or the integrated repository browser (slower).

Source Code Documentation

The newer parts of strongSwan use extractable inline documentation extensively. This documentation is extracted with doxygen for the latest release
and uploaded to

Code style

For our code we heavily use an object oriented programming style for C. Also have a look to our basic programming style guidelines.

Quality Assurance

Unit Tests

Our libraries are tested with an increasing number of unit tests. To run them use make check.

The following environment variables change the behavior of the test runner:

TESTS_REDUCED_KEYLENGTHS If this is set test cases that generate keys will do so only for reduced key lengths to avoid blocking on hosts with low entropy.
TESTS_STRONGSWAN_CONF Path to a custom strongswan.conf file used for the tests. Since 5.2.0.
TESTS_SUITES A comma-separated list of test suites to run (all suites are run if this is not specified).
TESTS_VERBOSITY The log level used when running the tests (-1 to 4, see LoggerConfiguration), defaults to -1.
LEAK_DETECTIVE_DISABLE If our custom memory allocator is enabled with --enable-leak-detective it can be disabled temporarily by setting this variable in order to speed up running the tests.

Coverage reports can be generated with make coverage (requires configuring with --enable-coverage, which is not recommended for production builds as it disables all optimizations).

The unit tests also run automatically on Travis CI:

Testing Environment

Our integration and regression testing environment helps us ensure the quality of future releases.

The results for the latest release are published online.


The src directory in the strongSwan distribution contains a set of components:

charon The IKE keying daemon.
libstrongswan The strongSwan library with basic functions used by the daemons and utilities
libcharon Contains most of the code and the plugins of the charon daemon
libhydra Contains daemon-specific code and plugins used by both the charon und pluto daemons
dumm An new and experimental UML testing framework in development.
ipsec The ipsec command line tool wrapping commands and other tools.
libfast A lightweight framework to build native web applications using ClearSilver and FastCGI.
manager A graphical management application for charon based on libfast.
openac Utility to build attribute certificates on the command line.
pki Public Key Infrastructure utility.
scepclient Utility to enroll certificates using the SCEP protocol.
starter Reads ipsec.conf and controls the keying daemon.
stroke Command line utility to control charon via the stroke protocol.

Removed since 5.0.0

pluto The old IKEv1 keying daemon.
libfreeswan The deprecated library used by pluto.
whack Command line utility to control pluto via the whack protocol.