From: David Miller <davem@davemloft.net> Date: 2015-09-10 03:20:30
From: Tom Herbert <redacted>
Date: Wed, 9 Sep 2015 17:51:19 -0700
Consider that ip_local_out_sk calls netfilter NF_INET_LOCAL_OUT hook
before dst->output, so then netfilter would start seeing packets
with zero source address???