This is mrd6, a ipv6 multicast routing daemon for Linux (and BSD).

It supports MLDv2 (and MLDv1 compatibility), PIM-SM (including SSM
support, BSR and Embedded-RP), partial MBGP support (IPv6 multicast
SAFI to populate the local mrib, when used in an edge), native and
virtual interfaces (ipv6-ipv4, ipv6-ipv6 and tun/tap tunnels have
all been tested extensively) as well as remote configuration (via CLI).
Automatic translation of IPv4 multicast traffic to IPv6 is also
supported (contributed by Teemu Kiviniemi).

You may use mrd6 with any Linux 2.6 based system as no kernel support
for ipv6 multicast forwarding is required, that feature is implemented
by mrd6 itself.

Build requirements: a GNU build system, including G++ and Make.

To build the default configuration, just run 'make', a 'mrd6' binary
will be compiled in src/. You can then install it (including
default configuration files and man pages) into your system using
'make install'.

For a custom build, run 'make config', where support for individual
features may be enabled or disabled.

For more information refer to http://fivebits.net/proj/mrd6/

mrd6 started being developed in 2004 and thus it's showing it's age.
However it is still a useful tool in certain scenarios, including
quick network prototyping, testing new network features and even to
run in embedded systems.

- Hugo Santos <hugo@fivebits.net>