In some mail from itojun@iijlab.net, sie said:
> 
> >One thing I did notice was the packets did not seem to have correct
> >checksums.  Have I picked the wrong place for intercepting IPv4 packets ?
> 
> 	to me bpf_mtap() in the middle of ip_input() seems to be the cause.
> 
> >Also, where on earth is the correct place in the KAME IPv6 code to add
> >similar hooks ?  I had a look but it was not clear where to go..
> 
> 	i don't think we should put any bpf_mtap() into ip*_input().  it
> 	belongs to layer 2, not layer 3.

Do you have a better solution ?

Darren