[Pkg-swan-devel] Bug#943457: libcharon-extra-plugins: Enable forecast plugin

[Grumpy]

It would be really great to have to forecast plugin included in
libcharon-extra-plugins :)

The forecast plugin allows, when specified/permitted by the traffic
selectors, to forward broadcast and multicast packets between clients
and subnets.

Multicast packets are widely used by "network discovery" protocols such
as Zeronconf/Bonjour and SSDP. The forecast plugin permits to replay
such packets in IPsec tunnels which allows services discovery (printers,
DLNA, ...) across clients/subnets.

Building the forecast plugin requires iptables development headers and
the --enable-forecast flag to the ./configure options.

Enabling the forecast plugin requires CAP_NET_RAW and the farp plugin
(which is already available in the libcharon-extra-plugins package).

The forecast plugin is described here:
https://wiki.strongswan.org/projects/strongswan/wiki/Forecast