Comment 2 for bug 1665960

1.
If the entity is a router created by neutron, then there is no issue
since the commit takes care of this scenario.
E.g.

   ext net1 net2
   | | |src1
   |---Router1---|---Router2---|src2
   | | |src3

2.
Your question is more about a SF performing routing/NAT.
E.g. In topoloy below, SF is a Router.

  ext |--SF1
   | | |--src1
   |---Router1--|--SF(Router)-|--src2
   | | |--src3
                |--SF2

In such a case, yes, you are right this commit will break things if only the logical-src-port is specified without the prefixes since it will insert the SRC IP address of SF(Router).

However, there are several easy workarounds for this.
1. - Specify the prefixes for the sources (most obvious one).
2. - Specify the SF(Router) interfaces to be router owned. (see below)

root@fs-10-145-105-24:/opt/stack/networking-sfc# neutron port-show 0f15bfa0-c522-4cc8-b04a-b2f92df2b7f1
+-----------------------+---------------------------------------------------------------------------
| Field | Value |
+-----------------------+---------------------------------------------------------------------------
| admin_state_up | True |
| allowed_address_pairs | |
| binding:vnic_type | normal |
| created_at | 2017-02-21T20:49:48Z |
| description | |
| device_id | 5f7d0f49-cbae-4f6d-9de5-773f37c9faf1 |
| device_owner | compute:None |

If the above SF is doing routing or NAT, then change the device owner to be network:router_interface instead of nova:compute

neutron port-update --device-owner network:router_interface 0f15bfa0-c522-4cc8-b04a-b2f92df2b7f1
root@fs-10-145-105-24:/opt/stack/networking-sfc# neutron port-show 0f15bfa0-c522-4cc8-b04a-b2f92df2b7f1
+-----------------------+---------------------------------------------------------------------------
| Field | Value |
+-----------------------+---------------------------------------------------------------------------
| admin_state_up | True |
| allowed_address_pairs | |
| binding:vnic_type | normal |
| created_at | 2017-02-21T20:49:48Z |
| description | |
| device_id | 5f7d0f49-cbae-4f6d-9de5-773f37c9faf1 |
| device_owner | network:router_interface

If the device_owner is a router_interface, the commit will not mess with it (not insert its source IP into the flow classifier)