Hi,

The version checks for the 'skb_get_hash_perturb()' function seems wrong on
the current tree source.

Comparing the kernel source of skbuff between kernel versions, only linux
4.2 has the function available.
http://lxr.free-electrons.com/source/include/linux/skbuff.h

There's a pull request on the github repo.

All the best,
Antoine Deschênes