netfilter: nf_conntrack: add generic function to get len of generic policy

Usefull for all protocols which do not add additional data, such
as GRE or UDPlite.

Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
2 files changed