Hi Harald,

The current definition of NFNL_HEADER_LEN isn't OK. NLMSG_LENGTH already 
includes the size of the netlink header. We have to use NLMSG_ALIGN 
instead. NLMSG_LENGTH is a bit misleading, I didn't notice this at first 
sight either.

BTW, I think that we should add some kind of versioning of libnfnetlink 
as well, still missing.

cheers,
Pablo