Remove all zero MAC address entries (00:00:00:00:00:00) from a multicast
packet's tracker TVLV before transmitting it and update all headers
accordingly. This way, instead of keeping the multicast packet at a
constant size throughout its journey through the mesh, it will become
more lightweight, smaller with every interested receiver on the way and
on each splitting intersection. Which can save some valuable bandwidth.
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Implement the preparation of a batman-adv multicast packet and use this
under certain conditions.
For one thing this implements the capability to push a complete
batman-adv multicast packet header, including a tracker TVLV with all
originator destinations that have signaled interest in it, onto a given
ethernet frame with an IP multicast packet inside.
For another checks are implemented to determine if encapsulating a
multicast packet in this new batman-adv multicast packet type and using
it is feasible. Those checks are:
1) Have all nodes signaled that they are capable of handling the new
batman-adv multicast packet type?
2) Do all active hard interfaces of all nodes, including us, have an MTU
of at least 1280 bytes?
3) Does a complete multicast packet header with all its destination
addresses fit onto the given multicast packet / ethernet frame and
does not exceed 1280 bytes?
If all checks passed then the new batman-adv multicast packet type will
be used for transmission and distribution. Otherwise we fall back to one or
more batman-adv unicast packet transmissions, if possible. Or if not
possible we will fall back to classic flooding through a batman-adv
broadcast packet.
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Implement functionality to receive and forward a new TVLV capable
multicast packet type.
The new batman-adv multicast packet type allows to contain several
originator destination addresses within a TVLV. Routers on the way will
potentially split the batman-adv multicast packet and adjust its tracker
TVLV contents.
Routing decisions are still based on the selected BATMAN IV or BATMAN V
routing algorithm. So this new batman-adv multicast packet type retains
the same loop-free properties.
Also a new OGM multicast TVLV flag is introduced to signal to other
nodes that we are capable of handling a batman-adv multicast packet and
multicast tracker TVLV. And that all of our hard interfaces have an MTU
of at least 1280 bytes (IPv6 minimum MTU), as a simple solution for now
to avoid MTU issues while forwarding.
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
