When snatting, from is not used

[gergnz]

Example partition:

partition 'x' do
  label 'd', :address => '10.243.4.97'
  label 's', :address => '172.17.7.9'
  label 'n', :address => '10.243.4.3'

  rewrite 'wow' do
    from 's'
    to   'd'
    snat 's' => 'n'
  end
end

Produces:

# x-58816d
iptables --table nat --new-chain x-d58816d
iptables --table nat --new-chain x-s58816d
iptables --table filter --new-chain x-a58816d
iptables --table nat --append x-s58816d --source 172.17.7.9 --jump SNAT --to-source 10.243.4.3
iptables --table filter --append x-a58816d --source 172.17.7.9 --jump ACCEPT
iptables --table nat --insert partition-s --source 172.17.7.9 --jump x-s58816d
iptables --table filter --insert partition-a --source 172.17.7.9 --jump x-a58816d

Where as I would have expect something more like:

# x-58816d
...
iptables --table nat --append x-s58816d --source 172.17.7.9 --destination 10.243.4.97 --jump SNAT --to-source 10.243.4.3
iptables --table filter --append x-a58816d --source 172.17.7.9 --destination 10.243.4.97 --jump ACCEPT
...

The same is true (but flipped) for DNAT. Sometimes you want to DNAT/SNAT on specific sources and destinations to a specific IP.