Currently one can use only a predefined set of advertised options in RAdv
protocol, which are supported by BIRD configuration. It would be convenient
to be able to specify other possible options at least manually as a blob
so one should not wait until it is supported in the code, released, etc.
This idea is inspired by presentation by Ondřej Caletka at CSNOG, in which
he noticed the lack of either PREF64 option or possibility to add custom
options in various software.
The patch makes it possible to define such options with the syntax:
other type <num> <bytestring>
The patch implements Default Router Preferences and More-Specific Routes
(RFC 4191) for RAdv protocol, allowing to announce router preference and
more specific routes in router advertisements. Routes can be exported to
RAdv like to regular routing protocols.
Some cleanups, bugfixes and other changes done by Ondrej Zajicek.
The patch adds support for channels, structures connecting protocols and
tables and handling most interactions between them. The documentation is
missing yet.
The RAdv protocol could be configured to change its behavior based on
availability of routes, e.g., do not announce router lifetime when a
default route is not available.
