Pavel Emelyanov wrote:

I've sent this patch some days ago to Bart, but with no answer...

When trying to do

	# ebtables -A FORWARD --among-src 0:12:34:56:78:9a=192.168.0.10 -j ACCEPT

on x86_64 box the ebt_among->check() callback warns me that

	ebtables: among: wrong size: 1060 against expected 1056, rounded to 1056

Checking the ebtables sources, I found that the alignment is done
differently in the tool and the kernel. Tool makes it like this:

	EBT_ALIGN(sizeof(struct ebt_among_info)) + X

while the kernel module like this:

	EBT_ALIGN(sizeof(struct ebt_among_info) + X)

So the suggested fix is to move the alignment in the kernel. After
the fix the rule is added and appears in the ebtables -L output.

It seems the kernel is correct and userspace is doing it
wrong, so I think userspace should be fixed instead.
The problem with your patch is that is causes misalignment
for following structures that contain u64 members.