[PATCH] babel: Use acknowledged retractions when losing a prefix

[Toke Høiland-Jørgensen]

Toke Høiland-Jørgensen <toke at toke.dk> writes:

> In order to prevent routing loops, Babel installs temporary blackhole
> routes to prefixes that expire or are otherwise lost. These blackhole
> routes are maintained for a while to ensure the route has been flushed
> from the whole network; the default hold time is 64 seconds.
>
> In the updated IETF version of Babel (rfc6126bis), an alternative
> procedure was added which replaces this hold time with an explicit
> acknowledgement procedure. This procedure simply consists of sending a
> retraction along with an acknowledgement request to all neighbours, and
> removing the blackhole route once all neighbours have acknowledged the
> retraction. As this usually happens pretty quickly, the hold time during
> which the route is blackholed is almost completely avoided.
>
> This patch implements the above behaviour. It adds a generic facility to
> the Babel protocol which allows for sending sequences of acknowledgement
> requests to a number of neighbours, and executing a callback function
> once all the requests have been ACKed. This facility is then used to
> implement the acknowledgement scheme when a route is lost.
>
> Signed-off-by: Toke Høiland-Jørgensen <toke at toke.dk>

Did anyone have a chance to look at this? :)

-Toke