This removes PKG_VERSION and PKG_RELEASE from most Makefiles, as the
value was never useful for Gluon packages; instead, PKG_VERSION is set
to 1 in gluon.mk.

It also removes two other weird definitions:

- gluon-iptables-clamp-mss-to-pmtu replicating the old PKG_VERSION logic
  from gluon-core, but without the fixed PKG_BUILD_DIR to prevent
  unnessary rebuilds
- gluon-hoodselector set GLUON_VERSION=3

With the removal of ramips-rt305x, the last user of
GLUON_SPECIALIZE_KERNEL is gone.

[Matthias Schiffer: fix up start/stop order and file permissions]

We must ensure that each node becomes IGMP/MLD querier for its local
clients; having only a single querier for the whole mesh is generally
unreliable, leading to frequent "IGMP/MLD querier appeared/disappeared"
messages from batman-adv and unreliable snooping.

In smaller meshes it might be interesting only segment querier domains, but
allow membership reports to pass through the mesh, in order to support
snooping switches outside the mesh without special configuration. A
site.conf switch is provided to control this behaviour.

Fixes #1320

This enables the ebtables internal locking mechanism which
will avoid race conditions between multiple, concurrent
ebtables calls.

This is a preparation for the upcoming gluon-arp-limiter
daemon, to avoid issues if upon restarting gluon-ebtables
the gluon-arp-limiter daemon tries to modify the tables.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>

macvlan interfaces never directly exchange traffic with the underlying
interface, but only with other hosts behind the interface. In consequence,
router advertisements from the uradvd running on br-client could never
reach local-node, preventing it from getting an IPv6 address without RAs
from an external radvd. Fix this be replacing the macvlan interface with
a veth pair (with the peer interface in br-client).

As a side effect, this saves about 5KB of flash, as the veth module is
simpler than macvlan.

This patch adds a new gluon-ebtables package to filter IGMP/MLD messages
via ebtables.

For one thing this reduces multicast overhead: About one third of all
ICMPv6 multicast traffic in Lübeck or Hamburg is MLD.

Furthermore it removes a potential Distributed Denial-of-Service vector
(see Gluon ticket #553).

Finally, it is a prerequisite for enabling bridge multicast snooping in
a decentral and robust fashion.

Note that IGMP/MLD are filtered for multicast traffic coming from
the mesh, too (new MULTICAST_IN), as unfortunately there seem to
be other queriers somewhere in the mesh at least for Freifunk
Lübeck. Also adding these rules to be prepared to anyone intentionally
or unintentionally disabling these filters on his/her node.

Node operators not running Gluon (for instance gateway nodes) should
make sure to either enable multicast_router towards bat0 or disable
multicast snooping entirely if they have a bridge on top of bat0.

Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>

Better configure these properly.