libsrs2 is the next generation SRS library from the original designer of
SRS. It implements the Sender Rewriting Scheme, a part of the SPF/SRS
protocol pair. Libsrs2 has been written from an entirely clean codebase with
compliance, speed and versatility in mind. It is platform independent and
has no external dependencies. It is thread-safe and heap-safe, and is
suitable for large scale applications and embedded systems and can operate
without many standard system facilities.