[PATCH] babel: Drop check for IF_MULTICAST interface flag

Ondrej Zajicek santiago at crfreenet.org
Mon Apr 19 13:03:54 UTC 2021

On Thu, Apr 15, 2021 at 03:44:50PM +0200, Toke Høiland-Jørgensen wrote:
> The babel protocol code was checking interfaces for the IF_MULTICAST flag
> and refusing to run if this isn't present. However, there are cases where
> this flag doesn't correspond to the actual capability of sending multicast
> packets. For instance, Wireguard interfaces on FreeBSD doesn't set the
> required flags, but Babel will run just fine over such an interface given
> the right configuration.


Is there a reason why to disregard the IF_MULTICAST flag? This seems to me
more like a bug in FreeBSD Wireguard implementation that should be fixed
there. Is this flag properly checked on Linux, or is there some reason why
the flag is missing?

Routing protocols in BIRD generally follow this flag (and perhaps use it
to switch to unicast-only mode), so i do not see why Babel should behave

Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."

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