My commit 6d55cb91a0 (gre: fix hard header destination
address checking) broke multicast.
The reason is that ip_gre used to get ipgre_header() calls with
zero destination if we have NOARP or multicast destination. Instead
the actual target was decided at ipgre_tunnel_xmit() time based on
per-protocol dissection.
Instead of allowing the "abuse" of ->header() calls with invalid
destination, this creates multicast mappings for ip_gre. This also
fixes "ip neigh show nud noarp" to display the proper multicast
mappings used by the gre device.
Reported-by: Doug Kehn <[email protected]>
Signed-off-by: Timo Teräs <[email protected]>
Acked-by: Doug Kehn <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Timo Teräs
93ca3bb5df